For the second week in a row it was all about tanks this week as Team Möbius continues to make fabulous progress building the hull for mv Möbius. Last week saw most of the tanks being built as sub assemblies and this week these were all lifted into position atop the hull frames in the jig and then connected up with the side legs of each frame being tacked into position. There is a LOT to show you and this will be a long post so get comfy with the beverage of your choice and let’s get to it.
I will let the pictures I took throughout the week do most of the talking and then have a sped up video at the end with a compilation of the video clips I shot to give you a bit more perspective on this week’s progress.
Picking up where we left off last week, the tanks are being built as sub assemblies and here Uğur and Enver are turning one of the last ones over.
Like this to finish welding the next set of baffles onto this tank. You can see other tank assemblies in the background ready to be lifted in place onto to the framework that has been assembled on the jig.
Here is one of the tanks ready to be lifted in place and slid into the space between two of the bulkheads that have been erected on the jig. These two bulkheads will form the ends of this tank. Each of these sub assemblies are actually two independent tanks as they are divided the Keel bar and baffle running down the centerline of the hull.
This overhead shot shows the close baffling of each tank and you can also see how these line up with the slots cut into each transverse frame for the longitudinal stringers and the large 25mm thick keel bar. Once the tanks are lifted in place on top of the hull (remember being built upside down) all the long length stringers and keel bar will be slid in place to line everything up just right.
This is a shot of what will become the tops of the tanks or the floor inside the boat. An aluminium plate will be welded on top to form the tops of the tanks and the 8mm flat bars you see running vertically and the one middle horizontal bar are to allow the tank top to be welded on. If I told you that the tank tops are welded on last, after the hull plates have been welded to all these baffles, frames and stringers, you might wonder how they can weld the tank tops to these bars? That is dong using a method called “plug welding” where the tank top plate will have a series of slots which line up along the centerline of these flat bars so they put the tank tops on top and then weld through the slots and then grind the welds off flush to finish off the floor.
Tanks all tacked up and waiting to be lifted in place.
Meanwhile, Uğur has started to tack some of the side frames in place which will form the framework for the superstructure above the decks. This is part of Frame #12 which is where the side decks run alongside the row of large glass windows down the sides of the SuperSalon. Uğur’s hand is where the side deck will run.
Moving to the opposite side and looking a bit further forward, more frames being assembled and tacked in place.
Here you can see a whole row of them as we look aft from Bulkhead/Frame #9. The plate you can see in the top of the photo is what will be the floor of the SuperSalon and the basement/storage area that is in the space now above this.
Peeking in we can watch Uğur put the framing in place for the side deck plates up near the front of the pilot house or Super Salon
You can see how the stringers we’ve been talking about so much slot into place and interlock with the frames so everything lines up just right.
and now one piece of the side decking is tacked in place 
Stepping back this shot looking forward shows that same deck plate and how it will soon have a mate aft of it. 
With all the plates for the tanks and baffles out of the way the bottom of the pile of AL plate reveals the two 25mm plates which is mostly used for the keel bar running the length of the hull as well as parts like the engine beds where we want these eXtremely thick plates for their sound deadening mass and strength.
You can see how they have cut the first length of the keel bar out and have cleaned off areas where it will be welded to frames that slot around it
This will give you a sense of the thickness of these keel bars.
Here are two keel bars stacked on top of each other wtih their ends ground off at 45 degrees on bot sides to create the deep groove needed for full penetration of the welds that will join them once they are positioned just right atop the hull.
Meanwhile, our Master Welder Sezgin is kept VERY busy welding up the miles of stringers and frames that have now been put into their final positions on the deck plates.
Here is a before ……………….. 
… and now an after shot of some of his handiwork all these staggered welds along each stringer where it joins the deck plate.
Can you guess what it means when these guys show up??
That’s right, time for the praying Mantis crane truck to show up!
Be sure to watch him in action in the video and I’ll show a series of shots now with the tanks being lifted and dropped in place on the hull
Doesn’t take long to lower the first one in place and the second one is lifted up …..
and dropped into place.
The ever watchful eye of Enver (center) making sure everything is just right while Uğur lines up the laser level and Umit is up on top directing the crane operator.
This section of tank was too long to be tacked up as one assembly so they dropped the first half in place and welded in some vertical supports to hold it while the second have is lifted in place.
Like this.
One more for today, our eXtreme crane has the forward half of the water tanks lifted in place
Umit, one of our other welders helps to pull it down onto the flatbar you can see behind him which was previously welded to the bulkhead as per the lines etched on it for the just right position.
This forward tank section under our Main Cabin is suspended in place temporarily with some vertical supports they are tacking on here.
The crane retracts it’s eXtreme arm for one last job while he is here today ……
……. lifting those big 6 meter / 20 ft lengths of 25mm keel bars into place atop the bottom so to speak.
Now you can see what those big slots in the frame bottoms are for.
Right now these planks of aluminium are just being set atop the frames and once all the frames are up it will be used to precisely locate each frame in just the right spot.
What do you think? Strong enough to keep us safe and help us SWAN (Sleep Well At Night)?
Our previous boat Learnativity was all steel and she taught us the value of having a rock solid bottom. For Möbius we wanted this hull to be another 2X stronger.
This plating is many many times greater than required for even the most stringent CE-A or MCA O certification but this eXtreme plating and construction is a big part of providing the mandatory confidence we think you have to have in your boat when you are going to be crossing oceans in all kinds of conditions and for the inevitable run ins with hard bits such as ice and rock from time to time. Dennis has carefully calculated all this mass of these much overbuilt frames and plating into the design characteristics to give us weight in the right places and plays its role in making Möbius a self righting boat which makes us feel VERY good.
With the the tanks and bulkheads all temporarily tacked in position, the frames can now be completed by adding in their side pieces. Here you can see that the aft frames have their sides tacked in place and the one in the foreground will have its side tacked in next.
Uğur holds the side frame component in position while Umit tacks it in place.
Enver tacks one more in place
The joints between frame pieces are positioned in the best location for strength and have their surfaces extended as you can see in the closeup here to create a weld that is stronger than the adjacent aluminium.
The pieces for all the frames for the aft deck area are laid out in preparation for their turn in the assembly process.
and in not time at all these are all soon stood up and tacked in place.
You can see how the flat bar overlaps each joint for added strength.
These overhead shots provide a sense of how the hull is really taking on her shape now.
and Sezgin keeps welding and welding and welding……….
Here you can see how the baffles connect up to the stringers and you can get an appreciation that it is not an exaggeration to say that there are miles of welding required to complete the hull.
Now you get a good sense of how the massive keel bar creates a literal backbone to the hull and when the frames and baffles are all welded in place it creates an extremely rigid grid for the hull plates to be welded to and makes for one of the toughest hulls of any ship you will ever see.
Just imagine how strong this hull will be when the 12 and 15mm plate is welded to this grid of tanks!
Whew! What a week! What a crew! What a boat!
Just another week for Team Möbius here at GreeNaval Yachts in Antalya.
Here is your weekly summary video synopsis that distills the whole week down to a few minutes. Fun for you to watch and you’ll get a good sense of the progression of this construction technique.
Thanks for coming aboard this adventure with us, wouldn’t be the same without you. And don’t be shy about adding your questions and ideas in the comments section below.
-Wayne
Absolutely AMAZING !!!
Thanks Joe. We’re having a great time with the project and looking forward to our container arriving next week, thanks to you.
You sure it wouldn’t be easier to get a hugh block of al and mill out what you don’t need?
hehehehe, you wonder sometimes don’t you John. However as mountainous the amounts of aluminium plate are here the spaces are orders of magnitude larger so subtractive machining wouldn’t really be to way to go. However as you and others have pointed out, an additive approach such as 3D printing might one day become an option. It would require a total rethink of boat hull construction to make sense and work well but I wouldn’t rule it out. One thing we have talked about is how future projects could reduce the time significantly by going after reducing the amount of cleanup and prep work for all the CNC cut pieces. Naval is going to be bringing CNC in house when them move to their new shipyard building being built now and should be moved into before end of this year. With your own CNC machine you could pick up on two main areas of person hour reductions; one in dialing in your plasma cutter to reduce the small bit of slag that tends to build up on the underside of the cut edges which needs to be ground off for safe handing and in the boat. The other is being able to use the same CNC setup to run a router spindle alongside the plasma cutter and be able to machine the cut pieces to either clean up those edges and more so to put a nice radius on all edges, around cutout holes and to even do some of those cut outs.
Dincer and I are looking at different CNC machines and setups now including how the first machine might be a dual purpose one that could be used for both metal and wood. In any case we are hoping to use as much CNC as possible for the interior cabinetry and other applications for cutting things like deck antiskid plates and fabrics. Stay tuned for much more on that as we move from this hotworks stage with all the aluminium and onto the systmes installtion and interior cabinetry.
Fascinating stuff! She is gonna be a big boat for sure. What do you estimate to be weight of aluminium alone on finished boat, excluding everything else? You plan to not have any added ballast right?
Yes, we are starting to get accustomed to her size but it will take awhile and seeing the hull literally emerge in the workshop is certainly making it a visceral experience. We never thought we would end up anywhere near this big and started out thinking something around 20 meters, 60-65′ would be plenty. Our previous boat Learnativity was 52 ft with a raised salon and pilot house and 2 cabins, 2 heads and we didn’t want for much more space as it is just the 2 of us over 99% of the time. However as we pushed on efficiency, pure physics entered the picture in the sense that the longer the waterline the more efficient the hull speed and so we made two decisions; go as long as possible on the WL for hull efficiency and speed, and then go as small as possible on the inside for interior space, cost and weight. 24meters is a line you don’t want to go over as a “boat” becomes a “ship” at that point and the rules and costs change dramatically so we went right up to that length. On the inside we went with the “empty ends” approach with a very large forepeak and workshop/engine room so out of the 24 meters only 13 are living space. I’ve asked Burak to work up an estimate of the actual weight of just the AL that will ultimately go into her and let you know when I have that.
And correct, no dedicated poured in place lead ballast as the lead in our big battery banks are serving double duty for this being centered and dropped right down on top of the keel bar in dedicated integral battery boxes welding in amongst the tanks.
Hi Wayne,
As I understand it, your tankage is comprised of integrated aluminium tanks. I can’t claim to do more than repeat something I think I read somewhere, but with that proviso I wonder:
1. At least in the EU, bio-diesel seems to be a thing. In short, that apparently increases the corrosion risk for aluminium tanks. I think I read that you will have plenty of access to the tanks, even with the baffles, for cleaning and maintenance, but are you considering painting the fuel tanks on the inside, as well to guard against this?
2. There are reports that potable water stored in aluminium containers/tanks *may* pose a health risk. Same question really: do you worry about that and if so, have you considered painting the water tanks on the inside?
I’m well aware that painting aluminium is not recommended if you don’t like frequent expensive maintenance. If either of the above does worry you, have you considered other measures?
At least for fresh water, common practise is that aluminium integral tanks are usually left unpainted but not used for drinking / cooking. There is usually separate, much smaller plastic tank for potable water.
Hi Carl, great questions and ones which shared the concern with and have researched extensively.
Starting at the end so to speak, here are the conclusions and decisions we have at this point in time:
1. For the fuel tanks, the concern for damage to AL tanks due to bio-diesel seems to be over stated with few first hand reports of such damage. I have read about 5 reports from detailed studies of this concern I was able to find online and while they confirm that there is the possibility of chemical reactions between some elements or biproducts of Bio-Diesel and AL it is relatively rare and minor.
2. I have spoken with or read reports from boat owners with raw AL fuel (and potable water) tanks and they report clean tanks with no observed problems after as much as 10 years of full time use. Of course there is no way to know how much or what type of Bio-Diesel these boats used but these boats have traveled extensively in most parts of the world so it would seem reasaonable to assume they are a good representative sample.
3. While the chemicals involved are different, the story seems to be about the same for water tanks; low probability of such damage or reactions, owners of boats with raw AL water tanks for many years reporting now problems and no first hand reports I have been able to find to the contrary.
Let me be clear, we take these concerns VERY seriously, having problems with either fuel or water given our eXtremely remote use cases is not something we take lightly and would seriously affect our lives and travel. My conclusion is that while the possibility of reactions between potable water and Bio-Diesel and raw aluminium are real and verified, the probability is quite low and there are measures we can take to reduce or eliminate such problems.
Water is the most “solvable” of the problems as we can control the quality of the water which goes into our tanks. We do so, as we always did with our previous boat, ONLY put in water which we have generated from our high volume watermaker. This means we can know with a very high degree of certainty, the quality and constituency of the water in our tanks. Keeping all water in our raw AL tanks “pure” H20 will pretty much resolve the issue. And to double down on the safety of our potable water we will also have as Andy mentioned, a stand alone plastic water tank with its own plumbing into the Galley.
Fuel is not as controllable in terms of what is in it but we will do the following to ensure that our fuel is as clean and safe as possible:
* One of the reasons for having such an eXtremely large total fuel volume (aprox 14500 L) is so that we can be very choosy about where and when we take on new fuel. We learned the value of this in our previous boat which had, for a sailboat, an equally eXtreme total fuel volume of over 2800L and meant that we only needed to fuel up every 1.5-2 years and simply waited till we got great fuel at a great price. After over 11 years and 50k nautical miles and I checked the tanks and found almost zero deposits in the bottom. These were steel fuel tanks and SS water tanks so does not cover the AL issues, but does show that we were able to keep things very clean thanks to the eXtreme filtration and polishing systems I installed.
* We are going even more eXtreme when it comes to the filtration and polishing sytems on Möbius. Each fuel tank will have a dedicated independent fuel polishing system built in using an Alfa Laval MIB303 centrifugal fuel/water separator and clarifier. In addition to very high volume processing this system uses no replaceable filter elements as it removes everything other than diesel by eXtremely high centrifugal forces to separate the different elements out and leave us with about as close to pure clean diesel as you can get. In addition we will also have more typical fuel filtration for each consumer, main engine and boiler. While eXtremely expensive to buy and install as you might imagine, this adds to our SWAN factor when it comes to our Gardner always having pure clean diesel to burn. I am not claiming that this eliminates the possibility of chemical reactions from Bio-Diesel and AL but I think this reduces the probability to a very low number and one we are confident in.
* For the water from the watermaker we will have an equally stringent and effective degree of filtration for the feed water by adding a diatomaceous earth water filter for all incoming sea water supply to the watermaker which will be the first level of filtration prior to the usual paper and carbon based water filters. These diatomaceous earth filters are what you might be familiar with from residential or commercial swimming pools and they work incredibly well. Very cheap medium which you can store aboard and replace about once a year or so, and allows you to do an easy and complete back flushing of the sand like media as often as you like.
So that’s where we are at regarding the interior of our fuel and water tanks, they all stay bare and we have all of the above systems to reduce or eliminate any elements which could react with our AL tanks.
Your thoughts Carl or others?