Christine & I are taking the weekend off to celebrate our 5th First Kiss-iversary and Christmas with a 3 day road trip up the coast to see more of the beautiful area we live in. Last night we had a gorgeous sunny day for our 2 1/2 hour drive up the coast to the little coastal town of Kos where we last stayed with some good friends on their sailboat four years ago. Today we drove down the coast a bit to spend some time in the ruins at Myra, near the down of Demre, which quite appropriately is where the real Saint Nicholas spent most of his life and was laid to rest. So I’m writing this up as we enjoy our 2nd night away, this time in the Orange Capital of Finike, another coastal town where we have stayed four years ago in the marina.
I will write up a separate post for those of you interested in this traveling aspect of our lives here in Turkey, but for now I’ll get you up to speed on the progress for the week on building XPM78-01 aka Möbius so let’s jump right into that.
As per this week’s title the most prominent progress was finishing the proboscis of Mobius as you can see her proudly displaying here,
and here with this topside view in spite of some fool’s hand getting in the way.
I wasn’t fast enough to get pictures while they were fabricating this nose section but the top and bottom are made from the same 10mm/3/8” thick plate as the rest of the Rub Rails and the front curved section was formed out of some of the 25mm/1” thick plate that was used to form the stem to stern keel bar and other robust frame members.
Here is what the fishies will see.
The bottom edge of the Rub Rails and nose now awaits Segin’s magic MIG welding touch to finish off this part of the hull.
As per the title this nose, complete with flaring nostril will quite literally lead the way as we eXplore the world aboard this awemazing XPM boat.
Stepping back a bit you can see that the boys have been busy cleaning up the foredeck area with their brass wire brushes and give us a better sense of how safe and strong it will be working the anchor and ground tackle from up here.
The vertical Samson Post will soon be capped off with a machined aluminium dome and a sturdy lengthwise running cylinder will run through the post making it quick and easy to secure the snubber rope lead through that big “nostril” from the anchor chain once we have the anchor set. This snubber line runs out about 3-5 meters in front and is secured to the anchor chain to act as a shock absorber as Möbius pulls and tugs with the waves while we are anchored. This prevents shock loading compared to if the chain were to be taking up these loads and makes for a much quieter anchor.
Doing an about face and looking aft you can see the rest of the well sloped anchor deck and the rest of the foredeck and the Pilot House which have also been cleaned up now that all the welding of the Rub Rails have been finished.
Next up that large opening into the Forepeak storage area will be framed in for the hinged all aluminium hatch to keep it all nice and dry and make it easy to get lines, fenders, anchors and such in and out of this eXtremely spacious storage area.
Dropping down to deck level you can see part of the 24m/78 ft long bead where the Rub Rail is welded to the deck. We may lay in another bead to increase the radius of this weld and it will then be ground down a bit to ease the edge a bit further and finish off this feature.
Moving aft we catch Sezgin up on top getting ready to lay down more weld as Nihat and Uğur (not seen here) have now finished bending this last length of the Rub Rail to the hull and making the transition corner onto the aft transom surface.
Team Möbius works with speed and precision and they soon have the aft Port corner all finished up…..
as you can see in this closer up view looking forward along the Port side Rub Rail.
Returning to the Forepeak we see that the interior is getting similarly finished off and cleaned up. This shot is taken from the outer aft corner of that big Forepeak hatch we saw earlier and you can see how well the pipe capped stringers work as a very strong and safe steps for climbing in and out of this storage area. The two access port frames have now been welded to the tops of what will be our Gray Water holding tank for our Master Cabin sinks and shower.
Once the lids are bolted down with their gaskets in place all these tanks will be pressure tested again to ensure there are no leaks and they will be ready for plumbing to be connected for the various hoses to fill, pump-out and drain these tanks as well as fittings for the Maretron and Hart level gauges so we have constant and very accurate tank level measurements.
Moving aft on the other side of the Forepeak bulkhead/wall which is now at the far end of this picture, we can see that similar progress has been made finishing up the access ports into these water tanks that form the floor of our Master Cabin.
That beautiful swirl pattern on the surrounding hull sides, frames and stringers is exciting to see as this indicates that these areas are now ready for the 50mmm thick EPDM foam to be glued in place. Our previous boat Learnativity taught us the huge values of having really well insulated boat and we are taking this to the eXtreme with Möbius. Our goal is to turn Möbius into a giant Thermos bottle for us to live eXtra comfortably in no matter what latitude we are in from ice outside to ice in our drinks.
Such eXcessive insulation might seem overly expensive and very time consuming to install but it pays us compounding dividends of by keeping heat in/out of the boat which dramatically reduces our energy requirements for heating and cooling systems. Add to this the significant joy of a library quiet boat under all conditions and you can understand why this is an easy decision for us.
Moving down to the shop floor off to the side of where Möbius sits, I can finally reveal the answer to the riddle I left you with a few postings ago asking if you could guess what that stack of aluminium rectangular extrusions like my wrinkled hand model is showing you were for.
Can you guess what these are for now?
Bingo! Uğur and Nihat have begun to fabricate the structure for the bimini/roof overtop of the SkyBridge. In addition to providing the oft needed protection from the sun or rain when we are up top, this strong and light structure will create the framework for mounting eight full size solar panels.
These solar panels, shown in dark blue in this quick render, will be sealed in place to the dark green bimini framework and create the majority of this roof surface.
The magenta coloured parts you see here, show another neat “convertible top” feature whereby the whole bimini roof structure is articulated with the hinged arch structure so that they can both be lowered down when we convert Möbius to “Canal Mode”. This reduces our air draft or height above the water is low enough to allow us to eXplore most of the areas in the world with large canal systems that typically have many low bridges over them. I will show you more of those details in future posts as the construction and mounting of this bimini progresses.
To further assist with your orientation and getting a good mental model of Möbius, the red vertical structures on the Aft Deck act as Vent Boxes for the Engine Room as well as providing space for our BBQ, sink and storage for wash down hoses, propane bottle and maybe some fishing gear.
The blue area between the two Vent Boxes is the large hinged hatch overtop of the whole Engine Room for installing or removing the Gardner and CPP.
If you click to enlarge these renderings, or any other photo, you can also see the Wing Boxes which flank both of the aft corners of the Pilot House and enable the thick glass side windows to extend all the way aft to create a very well protected space on both sides. The WT door into the SuperSalon is on the Port/Left side and the staircase up to the SkyBridge is on the Starboard/Right side.
Saving the best for last perhaps, while I don’t have a video for you this week, thanks to Antoine who is the Captain and Owner’s Representative of the big steel boat “Legacy” which you have seen sitting right in front of Möbius in previous posts, I’ve got something special to leave you with; Drone Photos!
Antoine just received the new DJI Mavic Air Pro drone that they will use when they are out chartering guests around the world aboard the fully renovated mv Legacy and so he was doing dome practice runs with the drone inside of the Naval Yachts shipyard and took these shots of Möbius.
Here is a great shot Bow on that will give you a good feel for the shape and scale of the Foredeck, Anchor deck and front of the Pilot House.
A Port side view of the front half to put this area into perspective.
The area at the bottom here where the air hose is coiled up is where the aft hinged fame with 3 more solar panels will sit and when propped up while we are anchored, creates a huge air tunnel to funnel all the fresh breezes coming over the bow down through the dark open vent area you can see at the far upper end of this space here.
Spinning around 180, here is a good shot of the SkyBridge area behind this vent which is what the bimini top will soon be covering, and at the very far end the integral roof overtop toe Aft Deck and Vent Box area you saw earlier keeping us shaded and dry when outside in those areas.
And lastly for today this bird’s eye view looking straight down onto the Aft Deck with the big ER hatch opening, the plinth on the aft Stbd/Right corner of the aft deck for plenty of headroom when going off the Swim Platform into the Workshop.
Thanks so much for sharing these with us Antoine and look forward to more as you master piloting your new drone.
And tha-tha-tha-that’s alllllllllllllllllllllllllllllllllllll for this week folks!
It is wine o’clock as the sun sets here in Kos and I’m back to join Captain Christine and the pups for sundowners.
Thanks for choosing to come along for this ride and we’ll be back wtih more next week.
As always, we encourage you to add all your questions, suggestions and comments in the “Join the Discussion” box below.
Hi Wayne, you mention Kiss-iversary. My wife and I celebrate our first kiss which was on 15 October 1966….
Best regards, happy anniversary, and have a great Christmas – Piers
Hi Piers and congratulations to you both for such a truly awemazing partnership since 1966. While our number of years are much shorter than yours so far, we enjoy celebrating all our different anniversaries from our “first contact” Email, to first Kiss, to marriage to wedding party and of course every day I get with my Beautiful Bride is a gift I don’t take lightly and remind myself and Christine of how grateful I am every day.
Mobius really looks good from the bird’s eye perspective Wayne, they put it in field of view, where you can really see all the different shapes she has. Looking good!!! Merry Christmas and I hope you are enjoying your road trip of your kissaversity.
Thanks Orville, those are views that even we don’t get to see and you’re right they do really help to get a better sense of the proportions. The more we see the more we like about how this design is working out. The only down side is that it has us longing all the more for being back on the water, but that’s a good longing and we are loving the process to get there.
Great shots! I’m in awe as I watch your creation take shape! Thanks for the great explanations.
Thanks and glad you’re enjoying the process as you follow along with us. All the thanks to Antoine who is the Captain of mv Legacy which is our “bay neighbor” here, for those great drone shots inside the new Naval Yachts shipyard. There will be more over time so do stay tuned.
Great progress, starting to get the feel how good she is gonna look like when ready!
BTW progress report on cousin:
Hi Andy, we’re enjoying seeing Möbius coming to life more and more each day. Like you we also follow the progress of Val and Stan with the launching of their new FPB70-1 Buffalo Nickel and all the more so now that Steve has regrettably shut down the FPB program and there are very few updates on SetSail anymore. There will be tons of great learning to be had from the breaking in process of Buffalo Nickel and I hope that Val will continue to find the time to share some of this with the rest of us with more blog posts. I certainly appreciate how much time these posts take and how busy they are right now getting BN all ship shape and ready to head out but hopefully they will be able to do more blog posts as they do.
Really hope they find the time to share their experiences with the boat. They did write a lot on their last boat, so I am optimistic.
FPB70 is so quite close in specs and construction to Mobius they are almost sisters. Would be so interesting to see how they compare in speed and fuel burn and overall behaviour when both are ready and steaming…
Happy New Years to you Andy and thanks for all your contributions here.
I join you in hoping that Val and Stan will find the time to write more about their adventures aboard the new larger Buffalo Nickel FPB70 as there will be much to learn as the start using the boat now and gathering the real world data and experiences.
There are certainly some similarities between BN and Möbius but mostly from quite a distance as they are vastly different boats upon closer inspection. They share the same overall length but the FPB70’s are quite a bit larger in most other dimensions. I don’t know final as built dimensions for the FPB70’s but based on what I’ve read they carry about 14” more beam and about 22” more freeboard. My understanding is that this was mostly done to increase the interior volumes to accommodate crew and more passengers onboard and in particular they raised the overall height of the Salon and Flybridge by almost 2 feet as I recall in order to accommodate “double decking” below the Salon/Great Room and add this significant volume of living space.
In our use case we don’t carry crew and we wanted to go the other direction and keep the living space “just right” for the two of us 98% of the time and then be able to very comfortably accommodate 2-4 visitors from time to time. We were also very focused on maintaining a very long, sleek and slender esthetic and so we worked very closely with Dennis on keeping all the above deck structures as minimal and as low as possible. You can see this difference most easily I think when you look at the overall proportions and side profiles of these two boats.
Below the water the two hulls are even more dramatically different with the bottom of the FPB70’s sweeping up steeply and early into a very flat and wide bottom aft. We preferred the characteristics of a round bottomed hull and less draft so as you’ve seen during construction here, Möbius carries her very round bottom all the way aft and has a prop tunnel so as is often the case two boats which initially appear quite similar become more and more different the closer you look. The overall displacement also varies considerably with the FPB70’s being about 14k Lbs larger based on the last numbers I have read and I don’t think this includes the external lead ballast tanks that were added on later in the build of the 70’s and 78’s.
None of this to say that either boat is “better”, just that they have been designed for different use cases by different designers and I think both models will serve their owners very well.
We too are very excitedly awaiting our chance to launch and see what our real world numbers and experiences are going to be like. Hopefully that’s where we will be this time next year!
Maybe one good detail to learn from is the problems they had with the steering pumps.
Why not have one electric steering pump, but another pump driven directly from main engine? Especially on FPB with already very powerful main engine bolted PTO-pump system for the stabs, but I think it would make sense on almost any powerboat even without them. Engine is already quite close to steering by default, so the lines would be reasonably short, much shorter than conventional manual steering lines anyway.
If the latter was (optionally) equipped with hydraulic driven pilot solenoids in parallel to autopilot driven electronic ones, could even have 100% non-electric power steering to boot, with hydraulic NFU-lever for example. Would make a pretty simple backup system.
Quite right Andy and I am anxiously awaiting the updates from Buffalo Nickel as they sort out the initial problems they have apparently been having with their steering pumps. Dennis, myself and the engineers at Kobelt have spent a LOT of hours over the past 2 years developing the “just right” steering system for Möbius and the XPM78’s and think we have come up with what will prove to be an eXtremely solid and fault tolerant steering system. We will be using Kobelt’s Accu-Steer hydraulic steering pumps and hence our interest in BN’s experiences but our cylinders and pump models are quite different and much larger so I think we should be well above any ability to overload them which seems to be what has been happening on BN.
As for your suggestions to have redundancy in the steering systems by combining one electric steering pump with one driven off the main engine, we looked into this option and it would be possible but the complexity and costs are very significant. For steering and AP you want the hydraulic systems to be dedicated to just steering and not mixed with other hydraulic systems such as active fin stabilisers, bow thrusters, windlass, etc. We feel that the costs and the risks are too high for this option and so we have instead gone with two redundant electric/hydraulic pumps and then a fully manual steering pump at the main helm for emergency backup.
Thanks for reply, for both the FPB vs Mobius and steering part. And happy new year as well!
Yes I agree FPB70 is a heavier boat and quite different in details, but it is still quite similar if you take eg Nordhaven or some semi disp boat of same LOA as a reference. Anyhow, it is gonna be interesting to see real world data or even better a group picture of them anchored together in some remote cove!
Regarding the steering system issue, this one I don’t fully agree. I don’t quite see why steering would necessary need a separate dedicated hydraulics circuit. They do mix different hydraulic users in to same hydraulic circuit in all kinds of machines all the time, be it industrial machines or aeroplanes or large ships, and they work just fine together. If your PTO pump has enough flow to run stabs and steering, both needed on long passage pretty much 24/7, I really don’t see why not and your main engine will naturally be running 24/7 as well. Just need some isolation valves to close a portion of circuit in case of maintenance or damage/leak.
But if you really wanted to, you could easily have a separate dedicated engine driven PTO pump and use it to feed one steering circuit. I don’t quite see complexity in it, it is a 99% same setup and hydraulic layout as electric steering pump has except for the electric motor being replaced by main engine turning the pump, and exactly same number of moving parts, maybe you need few more meters of hydraulic hose more but thats about it. I think this would be a quite neat and elegant system to have in parallel to electric driven pump, both with separate cylinders etc so each could be used separately and independently or both at the same time supporting each other if you needed extra power/maneuverability.
And regarding the cost, PTO pumps are not really expensive and all the other components – valves, solenoids, cylinders – would stay the same. After all PTO pumps cost hundreds of dollars, not thousands. As a sidenote, funny that hydraulics components are really pretty affordable as they are so widely used in so many fields and and if you bought all the components needed for steering, all the pumps and valves and solenoids and hoses and everything with plenty of spares as well, you would end up with a bill much less than what they ask for a ready made unit. And hydraulics is really not rocket science, if you can service your Gardner yourself, that is much more complex… But lets not get carried away, just something to think about.
Then a very biased, 100% personal opinion. I have worked with Hydraulic Projects Ltd from UK for work projects and I have really only good things to say on their service and quality of the products. And they do manufacture a lot of OEM autopilot steering equipment sold under different brands. Maybe would be good look into their steering pump solution as well (PC45)? On Accusteer units, there are some stories of them failing even when meticulously maintained. But as always, YMMV.
Thanks for the detailed comments on steering systems Andy. I have worked with industrial hydraulic systems on trucks, cats, diggers, draggers, etc. and I agree that the hydraulics in general and certainly the pump side of the equation is very simple and relatively inexpensive. However, it is all the other components that go into creating a full steering and auto pilot system where the devil and his details creep in as well as costs. The real “devil” here for me though is the complexity which I think you and I have a different definition or perspective on. My focus is on KISS from a safety and maintenance perspective and complexity in this context is not so much that of any single component but rather the overall systems and boat. In the case of steering our priorities as I have outlined are to have a system that is rock solid and has multiple levels of fault tolerance such that I can come as close as possible to eliminating the possibility of losing the ability to steer the boat. With double redundant cylinders, electric/hydraulic pumps, auto pilots, etc. and a final backup of a fully manual steering pump I feel we have the right steering system for Mobius.
PTO’s are another example where they too are relatively simple in and of themselves but they add another “system” to the boat and are very costly and heavy additions. For example Nogva makes an excellent PTO unit that fits between the Gardner engine and their CPP servo box and we seriously considered it and had it on the invoice for quite some time. But in the end it was a lot of weight and cost we don’t need. I already have a PTO directly off the Gardner that I’m going to use for one of the high output alternators. We have gone all electric on the boat systems rather than hydraulic so adding hydraulics would require adding a whole new system to the boat. Again, we seriously considered going to hydraulic for big loads such as winches, windlass, active stabilisers, etc. as well as steering but the all electric route is a better fit for us and so I am doubling down on ensuring our overall electrical system is eXtremely robust and fault tolerant.
I have looked into the Accu-Steer pumps quite extensively and paid particular attention to those which have had problems. However it seems that the issues are with one specific model, the HP212’s and the others have been very reliable. We are using the Accu-Steer HP300’s so much larger and they have a very good track record as best I know.
Thanks too for the link to the Hydraulic Projects constant running pump. I couldn’t find detailed specs on their site but I think our requirements are considerably higher than the one you linked to and our nominal pressure is 1000psi/69 bar for example. I’m sure they are good pumps and we could have perhaps put together a system using their parts but I valued the confidence I have in an all Kobelt system given my previous experiences with them.
The unit I meant:
And just for fun of it, for cylinders check out Parker Hannifin Lightraurics composite cylinders. They are light, tough, very corrosion resistant and just look so very cool.
And they are used onboard offshore racing yachts for the only use case more critical than steering I can think of, that is keel control.
I bet these are the only cylinders available that cost even more than Kobelts 🙂
Thanks Andy, no question that Kevlar and carbon fibre parts have a very high kool factor. There are actually a LOT of cylinders more expensive than Kobelt and we’ve researched most of them. However Kobelt steering served me extremely well on our previous boat and after 25 years they are still going along strong with only one rebuild of the seals in that time. Kobelt engineers have spent a lot of time with Dennis and I working out all the myriad of details for the overall steering, engine and CPP controls over the past year plus so I’m quite happy going with what I know to work well. Plus they’re Canadian like me so there is always THAT! 🙂
Btw, I just asked my colleague for a price for industrial hydraulic cylinder similar to Kobelt 7080. A 80/50X450 cylinder was closest match, though specified for a bit higher working pressure (210 bar) and loads (tons), anticorrosion coating included. You can literally buy 10 of those for one Kobelt and be left with some change.
I know it is 100% not the same and it being unbalanced does complicate hydraulic setup a bit – but not much -, but makes you (and me) think. A boat buck multiplier factor being 10x -100x is no myth.
Thanks for reply, as always! Interesting perspectives, I do fully agree on your reasoning, if not the details themselves!
You’re right, HPU300 is indeed much bigger pump, 11 liters per minute right? It is even a bit on excessive side, if I calculate right it gives hard over time of less than 8 secs with 16 inch 7080 and 1.5 liters displacement? Might be good to have “slower” passege pump in parallel, would give smoother autopilot steering and save heaps of electricity… After all you only need fast steering when docking or in violent storm, so less than 1% of the time I hope!
BTW HPU-300 has relief valve set to 750 psi so 50 bar according to manual, so it is about the same, but should be more than enough.
I think we are of closely like minded on the steering setup now Andy.
The HPU300 is as you note “.. even a bit on the excessive side” and that is all very much on purpose and in keeping with the X factor of the XPM’s, in this case what I might call “smart excess”. We are also like minded in the added advantages of having as you put it “…. slower passage pump in parallel….” as we are paralleling in another fully redundant steering system. Our whole steering and auto pilot setup is made up of two redundant and parallel systems each consisting of an Accu-Steer HPU300 connected to two Furuno auto pilots control heads (one at each SuperSalon & SkyBridge) with an accompanying NFU Jog lever. Each system (pump, cylinders, AP, etc.) has been sized to be as noted above, “a bit on the excessive size” or “slightly eXtreme” as I might word it for typical passage applications. We have sized the cylinders, pumps and AP such that either system A or B can be used independently to fully steer the boat at any time in most any conditions.
Both systems will be fully wired up and connected through a 3 way switch at each helm that allows the Captain to select either system A or B or Both. In the event that the current steering system fails, a simple throw of this switch shuts off the failed system and turns on the other. The option of turning on both systems running simultaneously gives us what I might call “power steering” essentially doubling your rudder turn rate that can be used from time to time to assist with just what you noted “…. you only need fast steering when docking or in violent storm, so less than 1% of the time I hope!”
Additionally we have designed the rudder to be similarly “eXtreme sized” in surface area and also able to turn through a full 45 degrees to each side. This large rudder and rudder angle then joins forces with our equally eXtreme 4 bladed 1m OD Nogva CPP prop which can most efficiently transmit all the torque from the Gardner to the water while powerfully but leisurely turning around 400RPM at 10 knots. This then becomes equally powerful at “zero speed” using the pitch control to feather between forward and reverse. As you can see, we really do take steering eXtremely seriously and regard it as one of the most critical systems on the boat. The combination of the double steering/AP systems, large rudder able to turn up to 45 degrees and the large CPP prop will hopefully enable us to fully control the boat at any speed, in any situation we run into and be as fault tolerant as possible.
All still somewhat theoretical at this point of course but the best we can do by design. Certainly will be fun to see what those rudder turn rates and lock to lock times work out to be on our sea trials.
And I must add, I am also definitely all in in going more/all electric route, but in some places hydraulics just has some unbeatable merits. Take a windlass for example, hydraulic motor is almost ideal as it packs much much higher power density, can be direct drive without gearbox, does not overheat, can be stalled forever and is almost immune to seawater and elements. But I would not run a kilometers of leaking hose through the boat, instead I would install a dedicated electro-hydraulic powerpack nearby in forepeak for example.
For steering, you could also go all electric and install Jefa electromechanical steering. Very precise steering and solid built units. Would be interesting option, and have a separate hydraulic system as an alternative/backup.
I’m a big fan of hydraulics as well Andy and we spent a lot of time making the decision to go electric or hydraulic for our high power systems such as windlass, kedging winches, bow thruster, stabilisers, etc. The benefits for the bow thruster were particularly compelling just as you noted. If we had gone with a “hydraulic boat” then like you I would have put an independent hydraulic system up in the forepeak to power all the big consumers up there; windlass, kedging winches, bow thruster and eliminate the need to have the very long run of hydraulic hoses from the aft mounted hydraulic power pack.
However as we walked through the various scenarios we know that while when you need a bow thruster you really need it and are very glad to have it, the reality is that we rarely use the bow thruster, typically less than 2-3 times per year and sometimes more than a year goes by without having used it. So a powerful electric bow thruster similarly eXtremely sized in keeping with all our systems will work quite well and eliminates that whole hydraulic system up front. Magnus Effect active stabilisers are very happily driven by 24 volt motors should we elect to go this route in the future and so it was our conclusion that we can go “all electric” and eliminate the multiple hydraulic systems entirely.
As you and I have discussed here at length, we are going with an electric/hydraulic steering system so it is not completely true to say that we are “all electric”. However in our case these dual electric driven hydraulic pumps are our auto pilot driven steering pumps and give us what we feel is the most robust, reliable and fault tolerant steering system so we are happy to make this exception to our otherwise all electric route for the boat’s systems.
And btw, one thing I would look into would be replacing the brushed motors in HPU with brushless ones – at least when/if the first set of motors fail. When looking at videos of people boating around the world, but also from own experience, it seems 90% of their autopilot (and also other electric motor) problems are to do with the brushes in some way or the other. Brushless motors take care of that, then you are only limited by bearing lifetime.
Yes, the “brushless revolution” is very welcomingly upon us Andy and I’m keeping a keen eye on it. Everything from my cordless tools to our big 400A alternators are already brushless and we’ll have to see if the motors on our steering/AP pumps as well as the many other electric motors in other systems can go a similar brushless route.
On the other hand my history with brushes on electric motors and alternators on our previous boats has been pretty good and something I can control to a reasonably large degree with good installation and setup and then good observation and maintenance over time so it is not a large scale problem IMHO.
Thanks for lengthy reply, I really admire the thought you have put into all the details and decisions! Thanks once more!
Just few small minor comments:
– for “passage pump” I was thinking a one with significantly less liters per minute, to make steering slower and smoother and thus save energy – both electricity and energy lost by rudder movement – on passage. The 4.5 l/min pump I linked would do more than just fine, and you can hook it in parallel to bigger pump to same cylinder by using a pilot check valve. For good passage steering ideal lock to lock time is more like 20-25s than sub 10s. Especially with solenoid actuated AP with no speed control.
– for max rudder movement, there are two schools of though – more is more camp with +- 45 deg movement, and the naval architect/hydrodynamics camp with +-35 deg movement. I tend to be moving to the latter…
– for docking and steering, I much prefer FU over NFU. Matter of taste, but with FU you can steer the rudder to right position without looking, so you can concentrate more on the actual manouver on hand and that dock approaching fast… Simrad FU80 is an excellent remote in my opinion, but I am sure Furuno has similar. A matter of taste, but I think Simrad autopilots are really the best available, and they do interface nicely with other brands as well. Other SImrad stuff, that is another story…
– I believe Magnus stabs will need AC power, at least all the units I know of. It can of course come from inverter, but direct 24VDC is a little low for 1.5kW peak power required.
I appreciate your questions and suggestions Andy and always glad for the opportunity it provides me to articulate my reasoning and logic and then adjust as needed.
I think we are close to your notion of a “passage pump” in that with just the one Accu-Steer HPU300 running our lock to lock time is estimated by Kobelt to be about 20 seconds and then get’s cut in half when we add in the 2nd pump. So we will see how this all works out in the reality of sea trials and our first year of passages.
I worked through the 45 vs 35 degree decision for rudder angle off center for many months and my conclusion was that while having the full 45 degrees of this oversized rudder would not be needed very often there really wasn’t much downside to having it for those times when it does come in very handy. I don’t we are likely to see anything close to even 35 degrees when at sea but will be very handy in close quarter low to zero speed manoeuvring in tight slipways. Having had a 45 degree turning big barn door of a rudder on our previous 16m/52ft steel sailboat I can attest to how effective this was and enabled us to spin that deep 3/4 keeled boat in its own length. I still put in a bow thruster in that previous boat and was also glad to have that in situations where we are also trying to spin or manoeuvre in high winds. The bow thruster often went for over a year not being used and it is a lot of expense and upkeep but it is also one of those “when you need it, you need it and nothing else will do” bits of kit and I know of two occaisons when I’m sure it saved other boats from being seriously damaged by our big heavy girl if we were not able to control the bow in those few situations.
So we will also be putting in a bow thruster on Möbius and expect that it will see about the same amount of use as well as the same degree of importance safety wise.
I have very little experience with joy sticks, either FFU or NFU so I’m having to rely on people who do such as yourself and what I can read and logically think through. My thinking right now is that the combination of the AutoPilot “knob” and the NFU joystick will work well for our use with no steering wheel and be the most intuitive for us. We always have rudder angle clearly indicated and usually in multiple places so we always know exactly what the rudder position is at any time and can then choose between rotating the AP knob or turning, “banging” as some, not me, refer to it as a “bang-bang lever”, the NFU jog lever. I see the utility of a FFU lever where the angle of the lever basically matches the rudder angle and acts a bit more like a tiller in a way. However coming from fully hydraulic steering on our previous boat we are accustomed to “no follow up” in the sense that the wheel and rudder stay wherever you leave them when you let go. It did take Christine a bit to get used to this having had mechanical steering on her previous boats and so the rudders always self centered when you let go while moving forward but she soon got the hang of the hydraulic steering and the need to turn the rudder back to center or whatever angle you wished. So I think the AP wheel, as well as the “jog buttons” on the AP control head and the NFU jog lever will be a good combination for us.
For close quarter manoeuvring the other big new characteristic for us, as well as steering advantage, will be running a boat with a CPP prop and being able to feather it seamlessly back and forth between forward and reverse with the revs staying the same. Having that big 45 degree turning rudder to push the water against should enable us to master docking after some getting used to time with this new system.
We currently plan to go with all Furuno nav gear including the AP control heads but would be most interested in hearing your experiences with Simrad APs and what leads you to prefer them. One very nice thing about the increased use of standards such as NMEA2000 and changes in attitudes of most of the manufacturers is that we are much more able to mix and match components from different manufacturers rather than having to go all in with just one. Still some benefits to having all your components from the same company and we have gravitated towards Furuno largely due to their more “commercial/industrial” nature and roots more so than “yachts” but I’d say that all the major nav gear companies are moving towards similar approaches and the differences are lessening. And always a certain degree of “matter of taste” as you state. I had gone with all Raymarine gear on our previous boat and was quite happy with that overall, especially after they were bought by Flir and we have not placed any orders for any of our equipment yet so we continue to research and consider all options and would be most appreciative of learning from experiences of others here.
I’m not sure about the latest MagnusMaster stabilisers but the RotorSwing stabilisers have direct 24v systems that seem to work well and is one of their features that attracts me. However at this point in time our plan continues to be going with passive paravane stabilisers and have the hull all ready for active stabilisers should we change our mind in the future. Indeed one of the several things I’m working on the most right now is the details for rigging and running our paravanes so you will be seeing more about that in the coming weeks of blog posts.
Thanks as always Andy for your thoughtful and thought provoking comments and suggestions. Very much appreciated and valued.
Thanks for lenghty reply as always!
Quick comment/note on autopilot:
– FU controller does not in any way need to be spring centered, in fact the Simrad FU80 does not have one:
“The lever will remain in set position, and the commanded rudder angle/heading change maintained until the lever is returned to mid-position.”
This makes manouvering very fast, precise and intuitive, like tiller as you mentioned but with power of hydraulics to do the work, and you don’t ever need to look at the rudder angle indicator, other than pre departure / arrival control check that is. And you can leave the controller to set rudder position and it will stay there. Once you get used to it, it is hard to have it in any other way.
– Simrad autopilots used to be Robertson brand, and under that brand they are the ones you would find aboard many fishing vessels, work boats, military fast craft etc. Ive yet to hear bad things from them and they seem to be trusted by the ones in the know. A bit like Furuno Radars, everyone buys their second radar a Furuno.
Btw, FPB781 is equipped with both, Simrad AP and FU80 remote and no steering wheel, and it is one of the nicest boats I had a pleasure to steer manouvering wise, for its huge size it feels much smaller, nimble even.
– And for steering effect a very short comment, 35 degree deflection usually has the maximum effect of turning, after that AoA gets high causing stalling of the rudder profile to start being excessive, and turning effect gets worse in fact. 35+ rudder angle causes some braking effect though, which might be beneficial, or not.
By less rudder deflection steering geometry can be made to be optimal, ie. have quicker response and more torque with everything else staying the same (cylinders, pumps etc).
And regarding the AP pump, when in close quarters and slow speed, 300 series pump is such a powerful pump it should be moving the rudder with more or less minimal load and thus pumping steering fluid at its maximal pumping speed of 11 L/min. If it does this, filling a 1.5L displacement Kobelt 7080 and thus turning rudder lock to lock should take 8 secs. Even if this is adjusted and reduced to be slower at 20 secs, adding another steering cylinder and identical pump in parallel pushing the same minimally loaded rudder would take same amount of time to pump that said cylinder and result in same lock to lock time, right? So I don’t quite see how two parallel pumps would double the steering speed, if they both have their own dedicated cylinders. If they were both connected to same cylinder then it would be different story.
Hi Wayne, first of all congrats to the fantastic boat you are building and finally someone with common sense to install a Gardner engine – whose fuel economy and reliability is legend. Coming back to the thread: the laminar flow of water disconnects from the rudder at more then 35 deg – as Andy said. This can be increased by end plates at top and bottom of rudder and/or build a fishtail rudder. Have worked with fishtail rudder with end plates and its gives nearly full side thrust with small forward component. Brilliant piece of kit.
Have you considered the installation of a propeller nozzle ? Manufacturers claim speed increase of 10-25 percent (some claim more) together with pre-swirl stators. Contrary to common believe they are not only for slow ships (tugs/trawlers) but can use NASA developed low drag/high lift profiles which put the border where the drag overcomes the additional thrust and renders the nozzle useless up to 15/16 knots? Dutch Yard Damen have build the smallest nozzles so far (they claim) with 50 cm dia and they use them as well for engine cooling in closed circuit.
Maybe have missed that in your extensive blog, but where do you install your cooling tanks and how was their volume determined (for arctic as well as tropic water temperatures)? Will the engine driven coolant pump be the only one to circulate the liquid or do you have any backup pumps in mind.
How does your exhaust system look?
Again a fantastic boat
Hi Bernd, glad you are enjoying the ride with us. Nice to meet a fellow Gardner enthusiast as well. We know this is questioned by many but for us this is a fabulous choice as it fits perfectly with our overall principles and use case for this boat. Rock solid, low revs, high torque, literally built like a tank and an engine we will likely leave in our will to our grandchildren when we’re done. And then as you noted, efficiency that is still almost unequalled by any production diesel engine to this day. Coupled with our big CPP prop we think we are going to be able to have outstanding overall fuel efficiency when crossing oceans and we look forward to bring you and the others the proof in the data once we set sail and have real world numbers to share.
As to rudder design, it’s true that 35 degrees is the upper limit for steering when underway, frankly you’d rarely see more than 10 in most situations. However where the extra 10 degrees comes in handy is when you are doing very slow speed, close to zero, maneuvering, docking, etc. We had this on our previous boat which also had “barn door” size rudder and we could steer her stern amazingly well with just the prop produced water flow and near zero speeds.
We’ve also looked over the fish tail or articulated end rudders on a few other boats over the years and I thought long and hard about putting this on Möbius. But I’ve decided we will start with just a “plain” rudder and then see how well it works and handles once we launch. Relatively easy to modify the rudder later if we find we need a bit more steerage from the rudder. So it is great to get your first hand experience with these types of rudders and know that they also worked very well for you.
We looked at Prop nozzles for a little while back in the early design stages with Dennis and from what I could garner at the time didn’t think they were the right set of compromises for us. However I’ll certainly take another look with your prompting. Damen has a huge presence here in the Antalya Free Zone so I can enquire more with them now that I know they have quite a bit of experience with nozzle design. They certainly have lots of benefits and we are a relatively slow boat and not too far away from tugs/trawlers so perhaps they make sense. I was under the impression that they added quite a bit of drag and other negative effects that took away from their overall efficiency but I’ll dig into them more.
As for engine cooling I’m a big fan of external integral keel cooling. Put this on our previous boat with a big 6 cylinder Cummins and worked like a charm. That boat was all steel so I cut lengths of 2” steel pipe in half and welded these to the outer hull plates in near where it turned to run down the big keel and cut a 2” 180 bend in half to do the U turn at the ends. My plan for Möbius is to do something similar but out of aluminium and I am looking to see if we can find some square or rectangular aluminium thick wall extrusions to use instead of the pipe so the extrusions are fully sealed and the welding to the hull is just to hold it in place. This shape also gives me a bit more surface area per meter length. However so far all the extrusions have very sharp 90 degree corners, which is the norm for extrusions of any kind, and I don’t want that as it will be more difficult to clean and the bottom paint will quickly wear through on the corners. So I may go with ½ round pipe sections again.
Calculating the lengths isn’t too difficult, just plugging my numbers into a few set formulas for this purpose which the likes of Gerr and Calder have. Based on my current calculations the big main water pump on the Gardner is more than enough to move this water and it doesn’t end up being more volume than the large radiators used in truck mounted Gardners. This creates a very KISS cooling system, we have no salt water in the engine and only use sea water for the Gardner’s massive oil cooler, the Nogva CPP cooler and a bit for the wet exhaust.
Speaking of exhaust, I’m also a big fan of wet exhaust and would have it on all of my boats. For reasons I don’t fully understand many think that wet exhaust and keel coolers don’t go together and have even been told by a few “old salts” that it won’t work. But they can’t seem to explain why, just “that’s not how we do it” and I’ve had great success with the wet exhaust/keel cooler combo and will go with it again on Möbius. The wet exhaust system is pretty simple as well; straight up and out of the vertical exhaust pipe coming from the Gardner exhaust manifold into a SS elbow of about 140 degrees with a water injection ring at the end of the turn and then down a short distance into a lift muffler/water separator combo unit and then horizontally out of that over to the hull side and down and out through an angled exhaust pipe out of the hull about 30cm above the WL. Super quiet system with the combined lift muffler plus water separator and just exhaust gasses coming out the exhaust pipe with all the water exiting silently via the sea chest. I may install a small secondary exit for the water that exits a bit above the WL to provide a visual proof that water is flowing but I will have one, probably 2 flow meters on the exhaust water pipe with alarms that go off if the water flow goes below the limit I set.
Hope that answers most of your questions and if not or you have more just fire away. Sorry it took me a bit of time to get back to you on these and thanks much for your interest and questions.