It is Christine’s Birthday today, Happy Birthday my Beautiful Young Bride! So I snuck away early Friday afternoon and we drove East from Antalya along the coat to the beautiful old town of Alanya and have a fabulous room up at the top of a hill in an old castle with a view out over the original Red Tower and the inner harbour. Here is a quick panorama shot to give you and idea of this fabulous old city or Alanya.
But not to worry, I’ll do my best to make sure this week’s Möbius progress update posting WILL happen before the weekend is out and right now there is a HUGE downpour that has already dropped more than 80mm/3” of rain in less than 2 hours so we are enjoying the view from our room across the the harbour to the mountains on the far side. Christine is busy working on her daily Turkish lesson so she doesn’t loose the “streak” she is on with them and I’m taking advantage of the time to get this blog post started. As you might have already noticed, this will be a much longer post than usual as there is much to explain and show you so settle into a comfy chair with a good beverage and let’s get started.
This week was particularly exciting as work started on building the new hatches for Möbius which we have been designing and deliberating on for many months. Having Xtremely great hatches is super important to us because they bring in most of the fresh air and all the natural light into both our Master Cabin and the aft Guest Cabin. We have lived aboard boats with hatches for decades but never with ones we would rate as great. Sometimes they are just not well sized, sometimes they open the wrong way for the breezes, or they let any nearby raindrop in. Worst of all though is that pretty much all of them start to leak at some point, especially ones up on the foredeck when on passages in big waves that often bring volumes of sea water crashing onto the decks and penetrating even otherwise good seals no matter how well you try to “dog” them down tight. So we were determined that we would find a way to have truly GREAT hatches on Möbius. Hatches that are Goldilocks by being just the right size in just the right place and oriented just right to catch the least bit of fresh breezes coming over the bow when we are anchored. And MOST importantly of all, hatches that would NEVER leak under any conditions.
Then I added in two more and perhaps two of the most challenging must have characteristics; one, the hatch frames had to be raw aluminium that was shaped and thick enough to be welded directly into the decks and underlying framework, and second the hatches had to be significantly above the requirements for them to be certified for a full self righting situation.
This is a tall order and set us out on a very long and winding search for many years now dating back to well before we decided to move over from sail to power and to design and build our own boat as we had already been on the hunt for new hatches for our last sailboat Learnativity for a long time. We’ve been to most of the big boat shows on several continents to talk with the various hatch vendors. We’ve tapped into all the online forums, magazines and trade journals we could find. We’ve talked to MANY fellow liveaboard cruisers, most of whom share our pain and spent time exploring every detail of their hatches. All of which helped us figure out what works and what doesn’t when it comes to hatches so we had a very clear sense of the key traits of a great hatch and we know what we were looking for.
It may sound like an episode from Mission Impossible or an obsession to some of you but I believe it is possible to design and build a boat that stays dry inside in ALL conditions and does not EVER leak. One key to this is that one of my primary rules is that there will be NO penetrations of the deck or hull which could ever leak. None, zero, nada. No bolts, screws or rivets which penetrate the hull. No parts mounted through holes cut in the deck and then sealed with caulking or the like. One of the places where even good hatches often end up leaking is through their mounting of the frame to the deck where water finds its way, often under very severe pressure from so called Green Water in high seas, through fasteners or through seals and sealants that fail over time. Hence my hatches had to be welded into the hull and leave a single challenge to being leak free; the gasket that seals between the hinged lid and the outer frame. Even this is a challenge, but a solvable one which lets me put all my focus on making these lid seals as leak proof as possible.
I’m sure many of you are shaking your heads at this point with a wry smile on your lips and a wish for good luck but we are accustomed to being on the hunt for parts and equipment for Möbius with equally as daunting lists of Must Haves and other requirements and eventually we were able to find a few companies who make truly great hatches. But, and you knew that was coming didn’t you, none of these companies carried their great hatches in our sizes or at all and so they would need to be custom built and this was going to take both too much time and cost too much so the choice was simple and a bit like Möbius herself, we would need to design and build our own.
This is not as difficult as it sounds as it is more a case of assembling all the various features which are on our Must Have list and putting them together into a single design of a hatch. None of these features are new in and of themselves so we are not so much designing a new hatch as we are creating our own combination of features and ideas from many different sources. This holds true for the design of the whole boat IMHO as there are very very few features truly new and never seen before features in any boat. What sets any given boat apart from others is the combination of features they select to use and how they put them all together.
I find Autodesk’s Fusion 360 to be a fantastic tool for doing this kind of evolutionary design work and I used it to try out my initial ideas for the Goldilocks just right hatch I’ve outlined above and ended up with the design you’ll see below. I have not had time to create any proper renderings of these so I will just grab some screen captures from within Fusion 360. I have coloured the two basic aluminium parts for clarity with the outer Frame in RED and the inner Lid in BLUE. I’ve made the 15mm/5/8” thick glass that is glued to the Lid and the partial deck surface around the outside of each hatch to be transparent so it is a bit easier to see what’s inside and added a bit of wood appearance to the inner wood liner which is all that will be seen from the inside of the boat.
* Red Outer Frame made from 3 pieces of 8mm/ 5/16” thick AL plate
* Blue Lid made from a 8mm thick outer flat bar frame welded to a top which is CNC cut as a single piece from 10mm/ 716” aluminium plate which then has a 15mm/5/8” thick clear tempered glass plate which sits flush with the other edges of the Lid frame and the top Deck surface.
* 20mm/ 3/4” thick wood inner liner which extends through the interior upholstered head liners.
I have omitted the handles and latch details for clarity but you can see where they attach to the two round bosses on the underside of the blue Lid.
Two SS gas compression lift cylinders are also not shown and will mount to the aft corner of the Gutter inside the red Frame and the side of the blue Lid to assist with opening when the latch handles are turned.
In the interest of time and what will likely already be a long post, the basic key design requirements I ended up with include the following:
- KISS (Keep It Simple & Safe) the design for both functional use as well as the fabrication of these hatches by using the least number of individual parts and keeping each one as simple as possible using stock aluminium.
- KISS the fabrication process as straightforward as possible requiring as few special tools, jigs and machines as possible so that it can all be done in house with our current capabilities.
- Design the hatches so as to eliminate any high pressure sea water forces from bearing directly on the seals so that readily available good quality seals will be able to easily keep all water out for many years of daily use and then be easily replaceable when they do eventually wear out.
- Ensure that the entire hatch is well above and beyond engineering and certification standards to stay intact and fully sealed in the case of a full roll over or self righting recovery.
- KISS the latching or locking mechanisms by having no external access for opening, all latches operate from inside only.
- KISS the latching system and have an ability for a varying degree of locking or “dogging” down the hatches over time as the seals may take some set.
- Present the least possible interference and disruption of the clean deck surfaces for both equipment and humans. eg. no toe stubbers or line catchers
- Maintain the lowest possible maintenance factor as with all other aspects of the design of these XPS boats.
Along the way to the final design I ended up designing these hatches to be completely flush with the deck surfaces they are welded into. I wrestled with this decision of flush versus having the hatch frame extend up above the deck surface by 50-100mm/2-4” or so which is typical of most hatches and which was how I had initially thought they would sit. I came up with several such above deck designs which would have worked very well but in the end flush mounted hatches won out through my version of “the process of elimination”. What is the most sure fire way to deal with those high pressure sea water forces being able to reach the seals? Eliminate them. What is the best way to keep the deck surfaces free and clear? Eliminate any part of the hatches being above or below the deck surface. By making the top glass surface flush with the deck any big seas that end up on deck will simply pass right over these hatches and leave the seals to just deal with any standing water that collects in the Gutter area you will see below that runs like a moat around the outside perimeter of the Red Frame inner and outer frames before it drains out the two holes in the bottom of the Gutter.
Notice anything missing in the rendering above? Where are the hinges??One of the trickier parts of creating a fully flush hatch is how to keep the hinges below the deck and this is what I came up with for our “hidden” hinges.
For clarity I have turned off the deck plate that sits flush with the red tops of the outer frames and made the Hinge Boxes that are welded to the red outer Frame to appear transparent so you can see the blue hinge arms inside. The 8mm Hinge Pins are in white.
The Blue Hinge Arms will initially be milled out of a single meter long piece of square aluminium stock to form the profile for the Hinge Arms you can make out in this and the rendering below and then cut and machined to 50mm/2” long lengths for each Hinge Arm which is TIG welded to the outer frame of the Lid.
For those interested in more details this section side view might help to see how the Deck (orange), Outer Frame (light blue) and Lid (yellow) all work together. I’ve turned off the seals that fill the gap on the top of the inner most vertical light blue Frame and the inside surface of the Lid.
The gap between the outer edges of the yellow Lid and the light blue Frame is about 5mm and there will be two 20mm diameter drain pipes for the water to quickly flow out through the bottom of the light blue horizontal Gutter frame where the Lid sits. The Latches and Handles are omitted here for clarity and will attach to the round yellow boss seen on the right side here.
There are ten hatches in total, all of them square, six large ones 700mm/28” square, one 600mm/24” and three 450mm/18”.
Whew! Hope that long explanation and renders help give you a good sense of what these hatches will look like and how they work, now let’s get back to reality and see how this design is being transformed into real aluminium.
It all starts with two full sheets of 8mm aluminium plate which the CNC plasma quickly cuts into the individual pieces for the ten hatches.
CNC cutting is a very precise method which creates this very small amount of scrap. One of the many great things about building with aluminium over other materials such as fiberglass, carbon, etc. is that every bit of scrap is equally efficiently recycled so all this goes into the recycle pile in the yard and is sent off to be melted down into new sheets.
As you can see here and noticed in the renderings above most of the parts of this hatch design are made from single lengths of 8mm plate, basically simple flat bars.
Only the Gutter bottom of the 3 part Frame which you see here, and the 10mm top plate of the Lid are cut out as fully formed parts.
The 10mm top plate parts are out being cut by a waterjet CNC machine as we want to have a fully finished edge out of the CNC machine to be flush with the edges of the 15mm glass plate.
As you have read in the intro, I really pushed hard on KISSing this hatch design to end up with the least number of pieces in the overall design with the least specialised tooling or jigs required.
I also spent a lot of time working out how these parts would be formed, assembled and welded to keep the build time and costs as low as possible.
The majority of the work to shape the parts was done with four equal large radius bends for the corners of the outer and inner Frames and the outer edge of the Lid frame. To do this, Uğur and Nihat quickly made up this jig for the big hydraulic press and did a couple of test bends to dial in the process.
We decided to build one full Frame first to make sure our methodology and tooling was optimal and this is the first bend of that first hatch Frame.
I designed the Gutter bottom to be a single piece so that we could take advantage of the accuracy of the CNC cutting to ensure that the outer and inner frames had to be the exact right size, all edges parallel and perfectly square.
Here is that first Frame with all four corners of the inner frame bent and being checked for fit. Using large clamps, the inner frame is then pulled tight against the inside of the Gutter bottom and then the overlapping ends you see up at the top of the photo are cut to the exact length and the inner frame is tacked together.
With the inner frame tacked together in precisely the right size Uğur welded both sides of the butt joint to turn the inner frame into a single continuous inner frame.
The same process is repeated to bend the four corners of the outer frames.
Then the outer frames are clamped tight to the Gutter bottom, tacked in position and the butt joint welded up.
The inner frame is reinserted into the Gutter bottom, clamped up very tight all around and tacked in final position.
The fully assembled and tacked Frame is then cleaned up and ready for final welding.
The upside down Frame in the back is one of the 450mm / 18” hatches and the one in the foreground is the 600mm / 24” hatch Frame.
Here is a close up shot of the Gutter I’ve been referring to which is where any water that runs down through the 5mm gap between the outside edge of the Lid and the inside edge of the outer Frame you see on the far right. This Gutter is 45mm / 1 3/4” wide and about 75mm / 3” deep and there will be two 20mm / 3/4” ID drain pipes welded into the bottom of this Gutter to quickly drain all the water down and back into the sea.
Sezgin arrives with his TIG welder and gets busy welding up the outside corners to turn the 3 pieces of the Frame into a single part which is then ready to be fitted and welded flush into the deck plates.
Outer frame fully welded to the Gutter bottom….
…… followed by the inner frame being fully welded and this Frame is ready for final machining and then fitting into its location on the deck.
I don’t think you need to know much about welding to agree that this is not only strong but beautiful work and it is a shame that it will never be seen once these are welded into the Deck, but we will all know its there and helps account for the huge grins we will all have on our faces when we launch.
I realise that these hatches are Xtremely Xtreme, over the top some will surely say. But will NEVER leak, and as the guy who has to live with these, sleep under them, maintain them and fix anything that goes wrong, I think they are well worth the extra effort and I could not be happier with the way these have turned out and look forward to showing you the next phase of building the lids and then fitting and installing the finished hatches into the boat.
The other bit of excitement this week was the Mr. G., our Gardner 6LXB main engine was lifted up one floor and moved into his new home and my new workshop for restoring him to better than new condition.
That is him hanging from the end of the extending boom of one of the many “Preying Mantis” cranes in the yard while Mother Möbius looks on over on the far right making sure her energy source is being treated well.
Now safely resting on the door into his new home on the first floor.
Ready to be rolled over to his place in this voluminous new workshop area where he will be lovingly restored and then taken back down and mounted inside Möbius in a few months.
It is now Sunday night and we are back from our FABULOUS weekend in the town of Alanya, about a 2 hour drive east from our home in Antalya. We walked our little hoofies off probably logging 20km over the two days and most of that as you can see was either straight up or straight down!
It was just as spectacular from our room at night.
The pano shot above is looking the opposite way from the previous one above, this one looking West along the coast towards our place in Antalya. Worth clicking on these shots to see some of the details of the castle and fortified walls of this town that dates back to the 12th century.
Before you go, while it is very short here is a time lapse video of some of the work this week and I hope you’ll enjoy seeing a hatch built in about 30 seconds!
Lest you think that hatches are all that has been hatching here is the latest progress photograph of the Dinc twins, Yiğit and Mert who as you can see are also making GREAT progress and growing up fast already.
Thanks for joining us and please do add your comments, questions and suggestions in the Join the Discussion box below.
See you next week,