Let the Building of the REAL Möbius Begin!

by Wayne | Apr 8, 2018 | Boat building, Hull, Wayne | 0 comments

Things are a bit more subdued with the building of Möbius here at Naval Yachts this week as we await the arrival of the truck that is bringing the aluminium plates for the jig AND the first set of AL plate parts for the hull.  All the aluminium is coming from Istanbul which is about 800 km north of us and the current ETA is tomorrow or Thursday, April 11/12 so we are now all anxiously awaiting the arrival of the first batch of AL parts.

In the meantime, we were VERY excited to receive some photos (thanks Burak) from the AL supplier/cutter in Istanbul of the first set of plates coming off the CNC plasma cutter and wanted to share some of our excitement with all of you who are equally patiently awaiting the start of actual building.

As per the title, the cutting of the first plate of aluminium means that the building of the “real” boat has now officially begun!  I say “real” boat because for more than two years now we have been very busy working with our fabulous designer Dennis Harjamaa at Artnautica Yacht Design in Auckland NZ and essentially “building” Möbius as a very complete 3D computer model.  While never completely fool proof this process of building a virtual boat allows us to work through most of the design and building challenges before any physical materials are cut or purchased which is a huge savings in time and cost.  And by having a very detailed 3D model of Möbius which includes everything from all the many systems, electronics, controls, lines, anchors, down to all the wires and pipes and even our clothes and cutlery, it has been possible to run computer simulations of the boat in the water to determine everything from hull efficiencies to roll and pitch characteristics in different weather conditions to the boats reaction to a full 360 degree roll in the water.  I will no doubt bore you with much, much more of these fascinating details in future posts as I go over the whole design process so stay tuned for that, or maybe keep your finger close to the Delete key!

If you click to enlarge this picture you will be looking at the first set of AL parts from the first sheet of 8mm plate.

To help understand what you are seeing in these photos you will notice that in addition to doing the actual precise cutting of the AL plate, the CNC plasma cutter is also able to just lightly etch the plate to “print”  text names and alignment marks.  Thanks to Dennis’ hard work, each part has a unique name etched/printed on it to ensure that we can pick up any one of the hundreds of pieces in this giant 3D jig saw puzzle and know exactly which part it is by name and how it is oriented within the hull.  If you look closely at the picture on the left (click to enlarge) you’ll see the first 2 parts are Bow Stringer #6 and Side Deck S9.  Look a bit closer at Bow Stringer 6 and you’ll see an S near the bottom of the photo and a P at the corner above it.  S for Starboard (right side of the boat when looking forward) and P for Port side so there is no question which side is up and how it fits into the hull.  Looking a bit closer you’ll see two small tabs that have been cut just above each of these letters and these fit into matching rectangular slots which will be cut into the AL frame #1 to lock them into just the right spot and then be welded together.

This part is one of the transverse (side to side) plates down on the bottom of the hull which forms the grid of plates which become all our massive integral tanks for fuel and water.  For added safety and long range pretty much everything below the water line WL is tankage and therefore even in the highly unlikely situation where something manages to pierce the thick AL bottom plating of the hull, it only penetrates one of the many integral tanks rather than breaching the interior of the boat.  I’ll go into much more detailed discussions of all this later but to put it in perspective we have a total fuel capacity of about 14,500 liters (3800 US gals) and total fresh water capacity of about 5300 L (1400 USG).  While you can’t see the ID lettering in this photo as it is up and off to the sides, you can see two other important features of the CNC cutting process.  At the bottom center you can see one of the many rectangular slots which matches up with a notch in the thick (25mm) vertical keel plate which runs the entire length of the boat and locks them together in just the right spot.  Beside this center slot you will see a series of rectangles have been etched into the plate indicating exactly where the longitudinal stringer ends are to butt up and be welded to this transverse frame plate.  In most places on the hull these stringers run the entire length of the hull and so these rectangles would be slots for the stringers to interlock with, but in places like this where the plate forms the end of a tank on one side and an air “void” on the other side, we don’t want the stringers to penetrate the tank and thus eliminate any chance of a leak where these stringers attach.

In most cases throughout the hull though, where two parts intersect they do so via precisely cut and matching slots, half depth in one part and half in the other such that they interlock and automatically align with each other.

I will be able to show this to you much more clearly next week or so with photos as the assembly of this giant Erector Meccano set of a 3D puzzle starts to go together.

For now these quick screen grabs from the 3D model version of Möbius will give you a good idea how this works.

Here is the Rudder Shelf Top plate, or part of it, and that large precisely cut hole is where the thick walled AL tube will be welded in place to hold the very robust 128mm rudder post shaft.  The smaller two holes in the upper left of the photo are two of the 4 holes for mounting the Stbd steering hydraulic cylinder.

I mention these seemingly minute details because the intent of doing such a thorough 3D modeling of the boat is to have the CNC cutter do as much of the cutting as possible and thus minimise the amount of hand fitting that needs to be done during the build.  As you can imagine and will see more and more as we progress through the build, the savings of time as well as the increased degree of accuracy throughout the boat is dramatic.

As you follow us through our process of designing and building Möbius you will see how this focus on efficiency permeates every step of our journey so far with Project Goldilocks.  The examples above of achieving efficiencies with time and costs through computer modeling and CNC cutting are what emboldens us to take on this immense project.  And as I will cover in future postings, efficiency dominates our whole approach to this project to make it as affordable, safe and comfortable as possible to build, operate and maintain our awemazing new floating home.

For today though, the first Aluminium plate has been cut and the building of the real 3D Möbius has officially begun!!