Inside Hull Ready To Paint - Well Almost!

This is a status report because 3 weeks have passed since the last post. I've been busy doing other things and there has been little boatbuilding. My aim has been to put in all the fixed woodwork inside the hull and to bring it to a state where I can apply 2 or 3 coats of epoxy and some paint. I wanted to do the finishing work before adding the deck and supporting woodwork, that is to do as much of the painting etc while the inside of the hull is easy to access.

I managed to put in a few hours yesterday and glued in the last two floors. I also shaped the side supports for the forward bulkhead and while doing that realised that I could not glue them in place until the deck beam above the bulkhead was also glued in. So I glued in the deck beam first and then the side supports. Here are a couple of photos showing the floors and bulkhead supports.

In the next photo you can see the "engine" bearers between the last 2 floors and also the steering quadrant on the temporary  (broomstick) rudder shaft.

Here's a close up of the homemade quadrant; laminated plywood with an aluminium bush. The two holes about halfway along the straight sides are where the ends of the steering line will come through to be clamped.

The next photo shows the two aft floors with the engine bearers fitted loosely. When the final drive arrangements are sorted out the bearers will be glued in place. The temporary propellor shaft is in place held in alignment by a couple of wooden bushes in the stern tube hole. The tapered pads on both sides of these floors are where the thrust bearings for the the propellor shaft will be bolted.

I've made a temporary bracket out of scrap plywood to get a feel for how the electric motor will be mounted. The motor runs at too high a speed (about 4000 RPM max) for direct drive and so will need to be geared down. My plan is to do this with a belt drive; small pulley on motor shaft and larger pulley on prop shaft to get down to about 1000 RPM at the prop. The white tin is about the size of the 3kW motor I plan to use. The motor is aprox 180mm diameter and 100mm thick - not very big!

Here is an overhead view, the big pulley (more scrap timber!) is 170mm diameter. When I sort out the final details of the belt drive the height of the motor bracket may be reduced.

Floors and Deck Beams

It has been a while since the boat was turned over and in that time I have been filling and sanding the inside of the hull. Waiting for the filler to dry so it can be sanded makes it into a one or two day cycle and because it is also boring I started working on the floors and then the deck beams.

Here is the start of laying out the deck beams. The aluminium box section is 100mm high; its top is at the waterline, its bottom is at the top of the floors. The cross pieces of scrap timber are where the floors will be.

This is how I found the shape of the floors. I could have obtained these profiles from the lofting but this is probably quicker. It isn't my idea, I saw it used in this thread on the Wooden Boat Forum. The pieces of cardboard are stapled to the crosspiece and then this assembly is lifted out and the shape transfered to a piece of scrap plywood.

The plywood should fit but if not can easily be fine tuned. Once the shape is determined it can be transferred to the real timber and cut out with confidence. In the middle sections of the boat where the shape changes slowly the sawn floor should fit. Towards the ends of the boat where the shape changes more quickly the sawn floors need to be bevelled to make a good fit.

In the next photo the two aft floors are in place ready for a pilot hole to be drilled on the centre of the propellor shaft which will pass through them. The drill is fixed in the end of a length of 16mm MS bar with loctite. The bar is long enough to reach through the stern tube hole and is held central in two bushes. The floor to be drilled is held in place by the pavers. Worked like a charm!

With the first pilot hole drilled the floor was removed and two wedge shaped pieces of ply glued either side to provide surfaces at right angles to the prop shaft. These provide the mounting surface for the flange mount bearings that support the inboard end of the propellor shaft. With the first floor complete a 50mm clearance hole was drilled through it. This allowed a pilot hole to be drilled in the second floor. Here are the two floors completed.

The rest of the floors were made and fitted through to the front of the boat. Since then I have been working on the deck beams at both ends. None of the floors or deck beams are glued in place yet but they are more or less ready to be fixed after the inside of the hull has some paint on it. 

While all of this has been going on it has occurred to me that the process of building a boat is one where large pieces of wood are reduced to smaller and smaller pieces. Here are a couple of photos of my scrap boxes. It is amazing how often I can find just the right piece of wood for a particular job in one of these places.

Turning the Boat Over

With the undercoat on and the hole drilled for the rudder shaft there were no more excuses for not turning the boat over. There were a couple of things to make however: a couple of big pulley blocks and the frames that would support the boat after it was turned.

Here's a photo of the pulley block. The sling that will go round the boat is 50mm wide so the pully is quite big. The whole thing is made of scrap ply, the pivot bolt is 16mm diameter and the eye at the top is an 8mm stainless eye bolt. The whole thing is plenty strong enough to hold the boat up.

Testing the block and strap. it all looks OK at this stage.

I made a couple of cradles to support the boat. Once again, I dragged out the plywood sheets that the boat was lofted on and took the shape of these cradles from the lines drawing. They fitted perfectly.

Now there are no more excuses. This morning I set about turning the boat. The steps in the process are quite simple. Put the slings around the hull and over the pulleys, lift the boat enough to remove the building frame, rotate the boat in the slings being careful not to hit the floor or overhead lights, put the cradles under and lower the hull into them.

First step, slings in place and ready to lift the boat up off the building frame.

Up in the air. The sheet is to stop the chains from my 1 ton chain block marking the undercoat.

Building frame removed. The boat is fairly stable in this position but it is top heavy so a bit precarious!

When given a little push it quickly moves to this position where it is very stable and needs quite a lot of effort to turn it the rest of the way. It is close to the floor and only just clears the underside of the pulleys.

This is when I encountered the results of my first mistake. These slings are actually tie down straps so they have the clips and ratchet to pull them tight. I didn't think carefully enough about the positioning of the clips and ratchet and this photo shows the problem. For the boat to turn any further the clips have to be moved. This took quite a while to organize: lower the boat onto a couple of stands to take the load off the slings and move them around the hull.

Here it is turned the rest of the way over. I could have used some help with this but managed it with levers and sky hooks. At this stage I had to lower the boat onto stands again and remove the pulley blocks to prevent the boat going back to its half capsized position - that seems to be the position where it was happiest.

Sitting in its cradles, all the lifting stuff removed and looking like a fantail launch.

First real view of the inside of the hull. There's some foreshortening in this photo which distorts the shape of the hull. It looks like a fairly easy cleanup job in this photo but all the damage where the plastic nails came through the ply and splintered the face veneer have to be filled and leveled. Not really a problem as the inside will be painted covering the filler in the holes.

Undercoat and Rudder Bottom Bracket

Here's the hull with 2 coats of International Paints PreKote undercoat.

I put the first coat on with a 25mm diameter foam roller and tipped it off with a brush. When it dried I found that my tipping off had left brush marks; I think that this was down to the brush not the paint - the brush had done a few miles on previous jobs! After a couple of hours sanding I put the second coat on with the same type of roller but didn't tip it off. Good result, the hull will only need a light sanding when the time comes for more paint.

Yesterday I picked up the bracket that bolts under the skeg to hold the bottom of the rudder stock from the stainless steel fabricator - bending 50x10 SS bar is beyond my capabilities. With the bracket temporarily in place I hung a plumb line from it to mark the position of the hole in the hull where the stock passes through. Once marked I made a dimple to start the drill in.

Here's the setup to drill a pilot hole through the hull and inner keel; that's through about 55mm of timber. Now the pilot hole is in I will make and fit a block on the inside to carry the upper bearing for the rudder stock. Once that block is in place I'll extend the hole through with a hole saw.

First Coats of Paint

It is a relief to have reached the end of the filling and sanding cycle although it might only have been replaced by the painting and sanding cycle. The painting began with the bare woodwork on the stem, keel and skeg. Two coats of primer, the first thinned with about 10% thinners.

Then 3 more coats of primer over the whole hull except for the stern tube hole, the area where the rudder shaft will pass through the hull and a strip around the sheer where the gunwale will be fitted. Light sanding after each coat of primer mainly to remove the dead flies and other debris. Here is a photo after the second coat.

The hull looks very different now it is a uniform colour. Once again I am surprised how many blemishes show up after a coat of paint!

Keel and Stem

I have been working on the outer parts of the keel and stem. The stem has been gathering dust since I made the blank some months ago. The keel blank is about 5 metres long, 80mm high and 75mm wide; it is straight but about 700mm at the forward end has a slight curve. The blank is 56mm thick Douglas Fir with 2 x 12mm strips of Tasmanian Oak laminated onto the outside edge.

Where the keel and stem join there is a hooked scarph joint. Here is a photo of the two pieces in place. there is still more shaping of both pieces to be done before they are fixed in place.

Over the last week I have removed most of the framework that the hull was built over. When I was building the frame I had in mind that it would have to be removed and tried to build it in a way that would facilitate its removal. In places this worked well. In others I simply had to cut the frame to pieces to get it out. I now have a lot of firewood and an empty hull,

The plastic nails that I used to fix the strips of plywood made many "exit wounds" on the inside of the hull. These were worse due to the tendency of hoop pine ply to split. The end result is not a pretty sight! Here are a couple of photos of the inside of the hull, looking forward first and then aft.

 The foreshortening in these photos gives a false impression of the volume of the boat - it is quite big!

This close up of the inside surface gives a better idea of the scale of the cleanup operation, lots of epoxy to clean off and holes to fill. This will all work out OK as I have always intended to paint the inside of the hull.

Fibre Glassing The Hull

It has been a long time since the last post with not much to take photos of or write about. In between lots of filling and sanding I have been traveling and sailing.

Here's a photo of the hull after I finally decided that it was fair and smooth enough. The patches of filler are where the hull had hollow areas; I'm not sure how these came about but suspect that the first layer of strips was not well enough supported by the building frame. The hollows occurred on both sides of the hull in the same places. There is a substantial fillet in the corner between the hull and the skeg to make the cloth go round the corner.

I decided to use 200 GSM cloth on the basis that the hull (15mm thick) is strong enough without the cloth and so the cloth is to provide some abrasion resistance and a stable surface for the paint. The next step was to overcome my apprehension about the process of applying the cloth and resin. After advice from other members of the Wooden Boat Association (thanks guys) and from Ross Lillistone of Bayside Wooden Boats (thanks Ross) I assembled all the materials and tools and finally got stuck into it (quite literally, resin everywhere!).

Here is the workbench with the necessary stuff. Across the front from left to right: Stanley knife, calculator and scales (I measured resin and hardener by weight - pour resin (250 to 280 grams) into one of the larger white cups, multiply it's weight by 1.44 and then add hardener up to that number), in front of the white container are 100mm squares of 1.5mm thick balsa wood to use as squeegees, the container of brown hardener is next and in the box under the green cloth is the resin with a 60 watt bulb to warm it up slightly. The tilted ice cream container holds some white vinegar for had washing. Hard to see are some cheap paint brushes, foam roller covers, and scissors. I tried mixing the resin with a stirrer in the battery drill (wing nut on a piece of threaded rod) but this was slower and not as effective as a flat plywood paddle.

Here is the cloth draped over the first side of the hull; I decided to cover the two sides on separate days to spread the work out. The cloth tried to slide off so I tacked it in place along the keel with masking tape. The plywood strip is pinned in place and holds the cloth up towards the corner at the skeg. The cloth with be overlapped at the stern; along the top of the keel I felt the overlap wasn't necessary because the rest of the keel and outer stem will be fixed over it.

First coat of resin applied. The surface is slightly matt at this stage because the weave of the cloth isn't completely full. This coat took a little over 2 hours to apply taking care that the cloth was stuck down with no excess resin underneath causing it to float.

Second coat applied starting when the first coat was still tacky but not soft (the waiting was the hard part). The surface is now more shiny. This coat was quicker to apply because it needed less resin (less mixing time) and it could just be squeegeed on, trying to keep it even and free of runs.

After a long wait because the temperature dropped in the afternoon the third coat went on. The resin was thickened slightly for this coat. I tried for a consistence like tomato sauce but I think my sauce was too runny; after the first batch I added more filler but maybe still not enough.

This coat took a little over 2 hours to apply. I trimmed the skirt around the sheer line with the Stanley knife, by this time the first coat was firm enough to allow the cloth to be cut easily. Cutting the excess cloth away where it wrapped around the stem was easier with a scalpel blade (much sharper).

The next morning the surface looked awful with runs and sags where my too runny resin had moved. This was expected and the lumps and bumps will be sanded away. No photos of the bumps!

Three days later (17/7/2016) and I have just finished the other side. Less stressful than the first side because I knew what to expect. For the third coat I made the resin a bit thicker but there will still be runs. As it gets thicker I find it is more difficult to spread in a smooth coat. I suppose that after a few more boats I will this sorted out!