Building Logs

On the level

Posted by Paul

The boat is back down. After a nerve racking little while jacked up in the air at a somewhat precarious angle, all the work on the rudders and under the hulls is done and the next little bit of work requires level and square again (level = fore to aft, square = level left to right). Actually the nerve racking wasnt so much the blocked on the angle, it was the lifting it up there a couple of weeks ago, and the getting it back down yesterday. In fact I think any time the boat moves on land will be somewhat nerve racking. In order to get it down I first had to lift it slightly to get it off the blocks, and the moment we lifted it we heard a cracking sound, still dont know what it was, but it scares the hell out of you when you hear it.

Terry came over and using the fork lift to lift it up off the rear cradles a few inchs in order to remove the timber blocks that were keeping the cradles up higher we began lowering her back down. The bows were sitting on truck tyres so we needed to lift the bows at the same time. So the blocks that came out of under the rear cradles were placed just forward of centre before lowering. This caused the bows to rise as the sterns dropped.

Then using the copper coat as a guide we adjusted the various blocks on each corner until we had the boat level fore to aft and left to right, using the car jacks. The boat is very stiff, as we lifted it with jacks forward, the stern would also lift off the cradle. We must have it well balanced because at one stage the boat was only sitting on 3 of the 4 cradles and we didnt even realise. The rear cradles have carpet over them and for some reason (I dont know why I did it) I decided to pull on the starboard carpet to centre it, with the boat on it. I wasnt thinking for a moment. But when the carpet moved I quickly realised that the boat was not resting on that cradle at all. So we got it level on both planes resting on 3 of the 4 points. Rather than jack it up again we simply pushed the starboard cradle forward until it was wedged under the hull tightly.

And back to level the correct waterline and the true rudder (to hull) profile is easier to see.

boat level again boat level again 1

The boat is a little higher off the ground now than it was before we lifted it, with the rudders in it needed to be just a few inches further off the ground. The rudders clear by about 2 inches. It is a relief to have it all back down.

The work I did before lowering her back down was to finish the port outboard door panel. Having already successfully made the starboard panel it was just a matter of repeating the process. And of course, knowing what worked last time made it even faster to make. Below pic is the panel as it came out of the “mold”, it pulls the sticky tape off the boat mold as it comes out, but the tape isnt stuck to the panel so well that it wont come off. A bit of grinding and sanding to get all of the dag ends (that are razor sharp) and overhangs smoothed out and level all the way around, and to take the sharp edges off and just slightly rounded and it is pretty much done. It then just drops straight back into the hull hole. Here and there a little filler to fill voids created by folds in the sticky tape, but otherwise not much else to do, the molding idea works a treat.

port outboard plate before clean up

port outboard plate very flush fit outboard plate and rudder tube from below

As I mentioned in the last post the panel is just slightly curved. This means that when the hinges are attached for the doors, the axles wont be in an exact straight line. Imagine that the axle of the hinges wasnt 2 separate axles but one long one, that is how much in line they have to be for the hinges to work properly, and because of the curve of the panel I needed to glue hinge platforms on so that the hinges would be on the same plane. To achieve this I cut out some thin (about 2mm) glass plates at about 70mm x 60mm (I have off-cuts of pre made glass plate in various thickness, some is polyester chop strand plate, others epoxy weave plate). I then temporary stuck these plates to the edge of a straight edged timber strip, in this case mdf using double sided sticky tape setting them the distance apart I want the hinges to be. Then I liberally smeared glue to the other side of the plates and applied them to the panels, straddling the door edge lines (I know the exact width of the doors just not the length yet), pushing down gently until glue oozed out from under them. I didnt want to dislodge them from the straight edge as they must set still attached to the straight edge so I was careful not to push too hard or sideways so as for them to come away from the straight edge guides. The double sided tape worked well. I had contemplated using a hot glue gun, but this was probably easier. When the glue set I removed the straight edges knowing I now had a flat platform on the slightly but nevertheless curved panel to mount the hinges. Now all I have to do is get them in line on the door edge when I cut it and all will work.

outboard door hinge plates attached to straight edges outboard hinge plates glued to panel

I havent cut the doors yet. I want to mount the outboard tracks and hang an outboard from them to get a better idea of how far aft the doors need to start for the outboard leg to clear (I am now launching with Yammie high thrust 9,9’s and these are a similar size to Honda 15/20’s so Terry will loan me a Honda 20 to test the tracks and mark off the doors). I want to make the doors as small as possible, later when I re-power to the etec 25’s I will make new larger doors. I will cut the doors in one piece at first, then down the middle to split them into 2. The main cut around the perimeter will be at a 45 degree bevel and maybe the middle cut also, the thinking being that the bevel stops the doors from going though the opening further than flush, although I will probably also glue on stops on the tops of the doors over hanging to the frames to further ensure that they cannot move past flush, but also that the angle may inhibit, even if only slightly, water pushing through the opening as a result of water pressure flowing past the hulls as it will have to travel around a corner to get in, but I am sure that that wont stop it much. I might have to make the aft cut square otherwise I will be presenting an appealing angle to oncoming water. I cant reverse the angle as this would inhibit the doors from opening. What I haven’t figured out yet is how to transition from a 45 degree angled side to 90 degrees should I decide to do that on the aft cut as I planned on cutting at 45 by tilting the jigsaw table. Perhaps I just try to freehand it until the cut is about square again then reset the table. Not sure yet.

This all seems to me like a futile task but I guess the idea of having angled door sides makes a little sense. I may put a scupper hole through the hull side to drain water out of the well at the flat area at the top of the buoyancy tanks, which is just above the water line but my fear is that when the hull drives down into the trough of waves as the bow rides up the next one I may just be adding a new place for water to enter the well. Maybe a one way valve in there might be the answer. Not sure about that one. Its a wet, flooded area by design and it may just work like a glass upside down immersed in water, the air pressure above stops water from entering any further than wherever the waterline happens to be at the time regardless of water trying to force its way in because of it rushing past the opening when sailing. But perhaps for that to work, the outboard well door above, as well as any where else that opens to the well (wiring conduits for the outboard umbilical for example) need to be sealed completely, and that cannot happen anyway because the outboards require fresh air to work,  in fact I will be either sucking fresh air in with a bilge blower and letting it exit where it can or pumping dirty air out with a blower and letting it enter where it can and if necessary will add vents if the motors seem starved of oxygen. Hmmm, I might have to consult the plans to see what they say. I haven’t looked at the plans for what seems like years. They can be somewhat lacking in areas such as this.

I also have finally got the outboard car bearings back. I dont like to use this space to complain about vendors, at least not by name and I know I whined a bit, with I think justified reason, about the time it was taking to get them done. But to say I am disappointed about what I ended up with for what I paid is certainly true. So I wont name them again, but I certainly wont be having them do my windows, even if they seem to be one of the few if only, places locally that has an oven to mold them in. What I ended up with I think I could easily have made myself. They will work just fine, but they are not what I originally asked them to make and when the price remained the same for a lesser job than I commissioned it just compounded the disappointment that this job has been from the start. I originally asked them to make me a C (or U) shaped bearing that would fit over the side flanges on the outboard cars and bolt through. I left them a piece of aluminium channel as well as both cars (hand made so the flange thicknesses may differ on each one). So, in all the job was to make a C shaped section of plastic to the right shape and size to run inside the aluminium channel, then cut a slot in it for the fibreglass flange, drill 3 holes, then over drill them each side to accommodate the bolt head and nut (and socket wrench over it). X 4 = done. Didnt seem like a big ask, in engineering terms.

how transom bearings work

What I got was a 2 part bearing, 2 blocks cut to size so that including the fibreglass flange they fit inside the aluminium channel, overhanging the fibreglass flange so as to create a bearing surface to either side of the flange. I feel I could have made that. Not sure, I have never tried to plane (machine) plastic, and this looks to be very very tough plastic, it seems to be glass reinforced so it is higher spec than I had originally thought. Anyway, I now have a slot down the middle of the side bearing surfaces I had not originally intended. I dont think it will be a problem. Anyway, I felt somewhat underwhelmed by what I got and paid for. $300 for now 8 parts. Seems high. Probably $50 worth of plastic. It is what it is, so lets move on.

Now that I have the bearings, and my transoms back I still had just a little work to do to finish them. The top and bottom edges of the outboard mounting plate, the ply pad sandwiched by the fibreglass, needs to be sealed. Using the multi tool I cut a slot at the edges of the ply and used a chisel to remove about 3mm of ply then back filled the edges with filler. This is to seal the ply from moisture so as to ensure it does not rot. Once all of the dry fitting is done I will remove the bearings, give them a light sand all over, then paint them and they are finished.

transom edge decore 1 transom edge decore

transom cars edge backfill before sanding transom cars edge backfill

Some time ago, on a boat builders advice, I removed the balsa core from behind the ply pads I had already glassed to the bulkhead inside the outboard well to act as stiffeners for what at the time was the sail track outboard motor rails. He suggested there would be a lot of torque twist load on the rails created by the outboards and that the balsa might be too soft to handle it. So I cut the glass away from the inside removed the balsa core and replaced it with 25mm plywood core and re-glassed it in. On the bottom half I then added another oversize ply pad. I only did this on the bottom half because on the starboard side it would be below the bunk and invisible and not take up any space and on the port side would be behind a washing machine and I could use them to anchor the washing machine to and also because I figured the bulk of the load would be on the bottom half of the rails, not the top half. The bottom half would have the outboard hanging off it when motoring, the top half would only have the outboards dead weight when sailing so not additional horse powered torque load.

It now turns out there is another good reason I did that extra work. When I originally fitted the sail track rails that was to be the original idea for hanging the transoms, I decored the balsa core about 15mm all around (so 30mm across) each bolt hole and back filled it. When I decored the entire balsa section and replaced it with ply I also had to remove the now rock hard decored sections. Had I not done that, these new C section aluminium tracks bolt holes are spaced 10mm outboard (20mm wider apart overall) so I would either have just missed both sets of holes with the new rails or hit with one side and needed de-coring again on the other because they would miss completely miss by 20mm and the outboards would be 10mm off the centreline of the hulls. (When Terry and I drilled and tapped the holes in the rails we used the sail tracks as the guide so the bolts could meet the pre drilled test holes already used when dry fitting and testing and ultimately failing the sail tracks). So I back filled the test holes. I will now need to re-drill the holes, over drill them, back fill them and re drill them.

It does get a bit monotonous but this precautionary work absolutely must be done. I have probably gone a bit overboard on decoring and core replacement but its better to be safe than sorry with these things. Soggy or rotten balsa is structurally useless and its bad builds in the past in these kind of areas that give balsa core a bad name, but done properly, balsa is one of the best boat building materials not just in my recently learned experience but that of many of the best boat (real boats, catamarans) designers around the world.

So hopefully, in the next few days I will have the motor rails fitted and the sail handling line pipes also fitted and another post to herald that the outboard wells are completed and the rear steps can finally go in.

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2 thoughts on “On the level

  1. Greg Smith

    Hi Paul,
    For the perimeter cuts around the outboard doors, why not use a router bit with that angle?
    It’s looking great by the way! Keep up the good work.

  2. Paul

    Hi Greg,

    I just thought that a jigsaw is the way to get the narrowest cut, as the cut-out becomes the doors. I think a router would make too wide a cut. Enjoy SCBS, let me know of anything interesting.

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