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.
Because of my trip to the US Feb was very short, only one weekend, but I have done a short log of what happened here and I will attempt to get a travel log of the weekend trip I did to Florida Keys when I get the chance, it is one of my dream cruise locations that one day I hope to tick off the list. Until then I got a quick taste as I was in Florida to visit the manufacturer of the hatches I import.
March 2011 ......................Aaaannndd, were back.
Sorry for that rather long break in transmission. We can now resume normal programming. I have been quite busy working on the boat but too busy (or lazy) to write and upload the blog. I do apologise. Now I said I have been busy, that's also not exactly true. Each year, at the start usually because of the weather being so hot I lose motivation to keep hard at it. It is something about the shed being a massive sauna with no way for the heat to escape that makes it unbearably hot whenever the outside temp exceeds 25 degrees. We have had most days exceed 30. It makes resin go off very fast even with slow hardener and is extremely uncomfortable. And it is about the only time I show any signs of epoxy intolerance. I am sure my body is close to saying enough already, but I dont see any symptoms unless its really hot, and then I get a rash on my inner forearms that shows for about a day or so then goes. Hopefully only a couple more weeks of this heat and then I have 6 months of clear work time to get most if not all the construction finished. By the time it warms up again I hope to be on the final finish work, that is fitting linings, upholstery and laminates. I should be well finished with sanding and grinding of hardened glass or any epoxy work.
In the meantime I am working on fitting the last quarter of the boat that does not have furniture, the main bathroom, shower and laundry in the Port hull.
March 13 Shower base, drain and web.
The bathroom in the Port hull sits behind the wall that makes the stairwell and under the galley. In that room will be a vanity basin and toilet (and an escape hatch) and through the main bulkhead (where most other boats of this design have the bathroom and shower) will be the shower with a door in its back wall and behind that door is the laundry where we will have a mini washing machine, water maker and water heater, probably gas instant. It was also going to house the black water tank in a cavity under the cockpit seating, but I was thinking about it and decided to move the tank closer to the toilet. I was a bit concerned about the toilet pump being able to push the 4 meters to the tank and the 1.5 meters up to it (remember pump in, gravity out). So moving it to the cavity that will be behind the shower side wall makes much more sense. Originally I was going to put the water maker in that space, but that would have meant having another doorway cut into the shower side wall. One less door means less work and will look much nicer.
Another advantage of moving the tank to behind that shower side wall means I will glass it in. I originally had it in my mind that I might need to remove the tank for maintenance and had to figure out how to get to it and how to get it out and keep it in. I had thought that having the tank closer to the pump out point that I will fit to the outside of the boat at the rear steps made more sense but now I realise that the pump on the vacuum dock system will be far more powerful than my pump up from the toilet. The really big advantage of having made this decision is the space it frees up in the laundry, so much so that I now have room for the washing machine and a laundry basin. The water maker still fits on the chamfer panel in the laundry in front of where the basin will be. And the shower side wall will add to the strength of the glassing that keeps the tank in place.
So having decided all of that, I glassed the tank supports in place. The pic does not mean much on its own but once the tank goes on and is glassed in it will all make sense. Next I glassed a keelson into the space that will be the shower and laundry. Even though there will be a web under the shower that would also strengthen the hull (the purpose of the keelson) I decided that there is a keelson in the matching section (under the starboard rear bunk) so for the very small amount of work and for symmetry I glassed in a cedar keelson.
I had already made the glass drain section and glued (pipe glue) a T section into it to accommodate the laundry drainage that will go past the shower drain and together they go into the sump that is on the other side of the bulkhead under the bathroom floor. The reason the sump is not under the shower is because I have put the shower base a bit lower than the bathroom floor so that we get more headroom in the shower (so the water has some fall and still hit us on the top of our heads) and because of this the sump would not be very deep. Either way a pipe or pipes would have had to go through the bulkhead, either from a sump under the shower to the holding tank behind the dagger case (and another one back) or in this case the shower and laundry drain through the bulkhead into the sump then up from the sump to the holding tank then back again to the through hull that is in the sump (so that if it leaks it is in a sealed off section that can either fill as it is below water level but sealed from entering the actual hull or the sump pump will send it back through the system and out again, so long as the pump can keep up it wont fill the sump but either way is safe). Also in the sump is the tri data sounder temp and log transducer). Again from time to time you pull the transducer up through the through hull into the boat, some water comes in until you get the plug in, this water will be into the sump so I wont panic as much doing this). The reason to do this is to service (clean) the log wheel from weed or growth if it stops turning. I assume you would know straight away if it is fouled as the speed over ground would go to zero even though the gps would show the speed and the plotter would show you moving along the map. Anyway, the systems on paper at least make sense to me.
The webs for the shower base have 2 functions. Firstly they give the base a solid footing so that it does not flex underfoot. But the height of the web cross sections have a staggered height so that at a flat calm the base is higher at the aft end of the shower so that water falls down the base into the drain grid and down into the sump. We dont want water pooling in the shower. Of course what is level on a flat factory floor (or slightly inclined) will at one moment be inclined the wrong way, then level then inclined correctly and so on, but you have to put it at some angle so it may as well be the right one for what you want it to do. I guess what that all means is that whilst not super critical, it is easy to cut each web so the angle works for what you want it to do. Then it was a case of cutting in the plumbing and dry fitting it all before glassing it all in, because once in and the base on its hopefully buried forever like any household plumbing is. I quickly learned for example that to get that pipe in I had to make an extra wide hole in the middle web, then push the pipe around to meed the T join then I can glass a piece back in to make it all solid so it cannot move before gluing and glassing the shower base on.
March 28 Shower base glassed in
With the plumbing under the shower base and the web for supporting the base glued and glassed in, glassing the shower base in was a fairly simple task, except that first the drain panel had to be glued and glassed in first. Then the duflex shower base went in under the aft edge of the drain plate and a screed of bog applied with a flat trowel in order to level the base to the drain panel and then a layer of glass was applied over that screed.
With the shower base in I moved to finish the black water holding tank that will now be behind the shower side wall and be glassed in permanently as opposed to being removable as I had been planning previously. The black water tank has an extra plumbing point that the other tanks dont have, in addition to plumb in for filling and plumb out (for emptying overboard) and a breather that all the tanks on board will have including the freshwater tanks, this tank had an additional plumb outlet for use with vacuum suction facilities that marinas and jetties have for emptying in port. This pipe has to start about 1 inch above the bottom of the tank and have an angled inlet so that it cannot be blocked easily, and then through the sealed tank lid and out to a hookup point on the outside of the boat so that the port facility vacuum out hose can be attached. Our vacuum attachment point will be on the back steps so that should there be any leakage, it is an easy hose down to clean.
I had previously lined the inside (and the outside) of the tank with white epoxy, I needed to key that lining so that glass would stick to it to glass the suction out pipe in. I decided to make the lid out of 9mm plywood. More because it was easier as I had off-cuts to the right size available. So once I had made the part, I glassed the inside, then once it is glued on I will seal it all by glassing the outside.
The tank with its fittings all in place is then positioned onto the chamfer panel so that the plumbing pipes can be fitted through the bulkheads and pipes fitted to panels so that it all works to plan. I decided long ago that the toilets already need pumps whether electric or manual to pump waste out of the toilet itself so it does not make sense to me to have the waste tanks under the waterline so that another pump is needed to pump the waste overboard. By having the tanks up higher than the waterline gravity is all that is required to evacuate the tank saving the need for another pump and the electricity needed to power it. My only concern has been that the toilet pump is capable of lifting the waste to the top of the holding tank. Its about 1.5 meters up and about 2 meters from the toilet now that the tank is relocated to behind the shower, I dont think the pump should have any issue with that.
Before the tank is glassed in I just need to have the copper gas line plumbed in as it travels behind the tank from the bottle on the duckboard to the cook top in the galley. Then once the tank is connected up and glassed in the side wall can be glassed on and the back wall with doorway also glassed in to complete the shower construction. The pipework above is not glued or glassed in yet as this is just a dry fit, but will be before the shower side wall goes on. The top 2 pipes are for pump out on the far right, then breather which will go along the wall then across the hull at the bulkhead then up into the mini mast I will fit to hold the wind generator (there will be a matching mini carbon mast on the other hull to house the radar dome, gps antenna and vhf antenna) and then exit at the top of this mast to keep the smells up high. Because the tank was originally made to fit at the other end of this room the chamfer shape, height etc is just slightly different enough to need some packing to make it a tight fit again before glassing it in. Other than that, this relocation is much better, its a better use of available space and much better for the pump to get the waste into the tank.
Another disappointing months work and I calculate that I have lost the combination of just under 2 months hours so far this year. I have managed just 110 hours in 3 months, when ideally I should have got to about 200 hours. I am going to give up making bold predictions of how soon I am going to finish this boat because Murphy does not like it much.
