Mahna Mahna

2010 building logs

The story of Mahna Mahna started the moment we decided we wanted to build our own Catamaran and then sail the world on her, but the actual building started in September 2005. The initial materials for our Schionning 1230 Wilderness Catamaran arrived from ATL composites and some other suppliers, over August 2005 and work on the strongback, the frame upon which the hulls are built, started in September. The journal starts with the building of the strongback. We will endeavour to pass on what we learn in the building process as we go and we welcome any questions or advise from anyone either following us or ahead of us in the journey. There are many different methods used by builders and the methods we use and describe on our site are suggestions only. You should always consult your designer and materials supplier for the best method of construction.

July 2010 Even More galley furniture

Well June pretty much was a month off. Whilst I was away I caught the flu, so after we got back from Vanuatu I was feeling too ill to work for another week, then having been off the build for 3 weeks I found it really hard to get back into it and felt lazy for another week, pretty much wiping out the month. So really I am doing the work I set out to do in June.

July 17 Finishing the lounge suite.

I should first up apologize that my posts are getting further and further apart, I set a fairly high standard early of almost daily updates but at the moment I am struggling to make one post a month, but I will continue to do my best to keep the log up to date, albeit infrequently posted.

After nearly a month off I got stuck into finishing the lounge, which meant cleaning up the inside of it so that I could coat it with white epoxy and stick the top on. But before I could do that I have to run a conduit through it so that wiring can traverse it. Actually I should explain. You might be wondering why conduit wasn't laid down before the lounge suite went in it is because I originally had no intention of wiring having to travel through it. I had intended for the wiring to cross the saloon under a false floor so that it would not need to travel around the room inside the furniture but directly across it. But I may not do the false floor now, so before I can put the lid on I have to make a path for the wiring (and the water pipes but they wont need to travel across the saloon, they will travel via the bedrooms aft and under the stairs in the port hull to the bathroom and kitchen, which is directly above the bathroom.

So now that a change of plan calls for conduit through the furniture I decided that there was no reason the conduit had to be across the bottom of the lounge suite so I ran it across the top of it directly under the lid. This had 3 advantages, first it would be much easier to retrofit the conduit across the top rather than cut holes across the bottom, not that it would take too much time to do that, another advantage is that up across the top directly under the lid it would be out of the way and finally, not that I am too concerned about this but the 2 middle under seat storage areas have venting so theoretically if we were ever pooped by enough water it could slosh through the saloon, slap into the lounge and splash up into the underseat area and if wiring runs across the bottom and there is any chance of wet wiring causing a short and frying the system I can avoid that by having the wiring running up off the deck in there.

Once I had the conduit in to take wiring under from the switch panel which will be in the port hull in front of the stairs just before our bedroom, it would then run through conduit under the fridge and into the lounge suite, then across the top of the lounge suite (but under the lid) then across the starboard hull and under the top step of the stairs into the nav cabinet to power the electronics. The hole for the conduit through the panel that is the bedroom wall/cabinet side/stair side. Whilst a hole saw could do the job quite easily, I have some holes to cut that I wont be able to get a hole saw to so I found an equally effective alternative method. I used the air powered die grinder with a router bit in it and cut the holes with it. Easy.

I cut the holes so that they would be at the correct height so that the step that will sit above it and conceal it will sit at the exact same height as the bridgedeck. Next step was to cut conduit to length and key it. Then once the holes were cut I glassed the conduit into place. I will glass the step in soon, I just need to tweak the shape a little so that it exactly matches the other steps and hides the conduit.

Next I white epoxy coated the underside of the saloon lid and the inside of each of the under seat compartments after feathering out the tapes and generally cleaning them up. I have done this to each storage area on the boat, I am not fairing any of them as some do, I dont much care what they look like, my only concern is that they are completely sealed and that the surface is smooth and there are no jagged edges.

With the inside and underside of the lounge white coated I glued and glassed the top down, using screws to hold it in place and taped the underside. Coving and taping upside down inside each compartment is a time consuming process and it took me all day to get the lid taped down from the inside. Once it had set (over night) I was able to trim (with a grinder) the ply overhang and route a round edge onto it to so that I can glass the top on from outside. A quick run over with an orbital just to fully smooth out the rough ply edges and I was ready to tape. Coving around the back edges and the tapes wet out and rolled out onto the job. Next I ran some coving into the edges of the step down where the top drops down into the rings glassed to the underside of the top that will hold the lids in place, in order to tape these too but I used surfboard cloth to tape these edges.

Then to finish off the main section of the saloon seating I white coated the top after giving the top and all of the tape edges a feather out to remove any jagged edges. I have still to make the final section of the lounge, the port side chaise. A chaise for those that are unfamiliar with the term is a right angle section of lounge that has no back on it, so it can be sat on from 3 sides front, back or leading edge. The reason I have yet to make the chaise is because it will need to be slightly raised from the rest of the lounge in order to fit under it a single dishwasher drawer which I dont yet have so I cannot be exactly sure of the dimensions until I have one. It is going to be a tight fit and whilst I can get the dimensions you are never really sure until you fit it so best to wait until I get one, even a scrapped not working model. Then from the chaise a cabinet will form the fridge.

So while I wait to get the dish-drawer I will move over to the galley and make the kitchen cabinets.

July 27 Finishing the starboard internal steps.

I guess I have slipped on the milk crate that is my lower step into each hull 1 time to many. If you step too close to the edge it just flips under you and over you go, and I am getting too old for it. I have been lucky, so far I have slipped about 10 times and never hurt myself but I am pushing my luck. So with the walls in both sides of the starboard stairwell I have decided to finish them.

The first task was to decide (and this has been part of the delay) how many more steps would go in. The milk crate is about 300mm high and splits the 600mm fall in half but the other risers are 200mm high so it becomes a question of whether to have 1 or 2 steps from the angle change from chamfer to hull side. 2 steps would be better as they fall is less and we are not getting any younger. The problem with 2 steps is that each needs to protrude further into the companion way than the one above so as to provide a clear footfall when coming down the steps. Going up is no problem but coming down is. And as the hull side is almost vertical (the angle is only about 10 degrees off vertical) it makes the steps almost directly below each other meaning you need a bigger step to have it protrude. So more steps mean more space taken up in what should be a clear companionway in the hull. So you can see the dilemma. Like everything else on a boat if you use space you are taking it from another area.

After much internal debate I finally decided on 2 steps but because of the amount of space stolen from the companionway I decided to steal some of it back from the cupboard that will be directly opposite the steps. This cupboard was already too shallow to be of much real use so curving it to return the space to the hallway made more sense than having what are already impractical shelves anyway. Now they are near useless so having doors on the cupboard is starting to seem silly, so I will either leave it open or close it permanently, that is another decision I have yet to make.

Back to the steps. Using cardboard I experimented with shapes and sizes for the steps. The first and obvious starting point was to continue with the shape already established by the shape of the steps already in place which provided the curve for the front but not the depth. I decided on the correct size and that step was easy enough. But the bottom step proved more difficult to create. The fall from the step above meant the step had to be bigger but not too big so it worked well but the bottom step needed to be huge in order to show itself from above on the near vertical fall. I also made this step in the shape of the steps above but because of the size it needed to be it was too big to fit inside the dimensions of the cupboards it is set against and it protruded about 100mm. I then experimented with shapes until I had the footfall I needed and it blended back into the cupboard it abutted. The shape did not match the others but it worked and looked ok.

So having decided the shapes were right and having tested them by making duflex steps and suspending them at the correct heights using blocks under them and ensuring that both Jo and I could use them easily both up and down I prepared them for installation. I de-cored the front edge and back filled them. I cut the supporting webs that would go under each step and cut the glass to length awaiting them being glassed in. Of course the back fill meant that another day was needed until they set. One of the great advantages of backfilling is that you can use the back fill to fair out any unfairness in the curves caused by poor saw work.

After the various incarnations of the steps and the final layout agreed to and the realization that the bottom step does eat into the walkway and demanded another compromise on the shape of the cupboards that will go in opposite the stairs. I had originally intended it to be straight (parallel to the center line) and be 300mm deep at the top (it narrows as the hull moves inwards toward the centerline the lower you go). It matches the depth of the cupboards in the bedrooms. But due to the bottom step making the walkway somewhat narrow I have decided (well actually Jo decided) that not only would it be more important to have a wide enough walkway rather than more storage space but that it would look much better and be in keeping with all the other curves I have already made in the boat. I countered how much more work was involved in curved front cupboards but it fell on deaf ears! I should also note that the motivation to find a shaped step to accommodate footfall also came from Jo. I mentioned to Jo that I was having difficulty getting the steps to work whilst maintaining the same shape steps and she reminded me that the bottom steps or indeed any of the steps could be any shape I wanted as they do on other boats.

Again I experimented with cardboard shapes before settling on the final shape of the curved shelves. I tried to maximize the internal volume of the cupboard and depth of the shelves but all but the top shelf were always going to be near useless for anything but very shallow items so I transcribed the curve shape of the all but the bottom step into the shelf shape. The bottom shelf is so shallow that it is hardly worth having it so I may close it permanently or leave it open, in other words no door on it. This adds to the feel of depth as there would never be anything on that shelf (it is only 50mm deep at the center and 100mm deep at the ends) or if I close it permanently it means that the doors for the shelf that is deep enough to be somewhat useful only will be behind that door, which would be the same shape as the curved and permanent front below it.

Again once the shape was decided with cardboard I transferred the shapes to duflex, cut them out and de-cored and refilled the front edge. I will glass these 3 shelves into the boat then use them as a template for the shape of the door. I contemplated doing all of that off the boat but I would need to replicate the angle of the hull outside panel, but that required a bit of working out on my behalf so I decided I could get it done well enough on the boat, the front panel would come off again to be faired and cut into the size doors I decided on (probably cut into 3, half along the middle shelf line, then the top half in half again to create 2 doors. But again before I can glass them in I have to wait for the core fill to harden so I can fair it. It is much easier to fair it off the boat on a bench than in place.

So with the steps core ready for sanding I ran a long board over them to fair out the front edge to the correct curved shape. I then glassed the third step in. I did not glass the bottom step in because at the last minute, after discussion with Jo we decided on whether it was wise to have a kick board on the bottom step or not. The argument against was because it is such a deep step that perhaps it would be better to have the ability for your foot to fall under it when moving through the walkway. On the downside it is a dead area, that would gather dust and things could roll under etc. In the end the compromise was to have the kickboard but have it set back further than in normal to close the area off whilst still providing a wider sole area for peoples feet when walking through the area or up the steps.

The bottom step underside provides the template for the kickboard. By following its contour but set back 50mm I was able to kerf a flat panel (with the kerfs hidden on the inside) to the curve. The curve is tighter at the forward corner so it required way more saw cuts to have the panel bend around the required curve. I then screwed it to the underside of the step in place following the traced line 50mm in, with a sheet of plastic between the front and the underside to ensure the front does not stick to the step whilst it sets, with glue and glass tape on, to shape. Here I had another dilemma.  By its nature it is impossible to glass all edges of a box inside and out. One edge or more will always go unglassed unless you can get inside the box somehow. In some cases as in the forward bulkhead to deck inside taping, I need to cut holes in bulkheads just to get to them because they must be done. I toyed with the idea of glassing the curved kickboard to step first and glassing some webs into the boat that this step and front would rest on (with glue) then I can glass the outside of the step and front, but this would mean the underside of the step would not get glass. I decided it would be better to glass the step in first both over and under along with the webs each side (fore and aft) leaving only the front to glue and glass in. This would mean that the front would only have glass on the front but it is mostly decoration and not structural so it can bear to be only glassed on the front.

While all of the work on the steps was going on I also started to set out the port bedroom. This bed will go across the boat meaning part of it will extend over the chamfer panel in the form of an island with steps up either side. Again we have the dilemma of space. No 2 things can take the same space at the same time. In order to make the steps as wide as possible I am going to cut the corners of the end of the bed (these can be curved but most likely not) in order to steal a little of the space at the end of the mattress in order to make the steps wider than they otherwise could be if I did not do this. Also remember that the front steps are further compromised by the position the mast base will take up. Then there is a third complication, again any space taken up by steps is space that is also taken from the cupboard space below the bed overhang. I feel like a juggler at this point trying to meet the requirements of 3 competing needs not to mention the aesthetics. Anyway I think I have the correct compromise. Next task in this job will be to go to the cardboard!

A 70 hour month, not quite as many as I should have done, (I am still aiming for 90 hours a month) but a fair effort. I am at 3227 hours and I believe I have about 1000 hours to go. If I can manage 90 hours a month I can achieve my other goal of finishing the boat in a year. In the end the boat will end up with nearly 5000 hours because I will be hiring some help to fair the boat including painting and also to work on interior linings and windows and combined these guys will probably add another 1000 hours on top of the 1000 hours or so I still have to put in. The irony here is that there were times during the build where I was feeling particularly encouraged that I would finish the build in about 3000 hours. And now that I am well past 3000 and can see I have about another 1000 of my own hours and another 1000 of hired hours I am not in the least surprised. I guess at times during the long long build we self talk ourselves into anything that seems to minimize the job ahead. Now that the end is in sight (I still lose sight of it from time to time) I can be a little more rational about what is still left to do and whilst I think I can do it all in a year, I can see how that could easily blow out to 2 if I dont keep hard at it.

Time Spent: 70.00 Hours

Total build time so far: 3227.00 Hours   Total Elapsed Time: 4 Years 10 months, 4 weeks

August 2010 logs