Pathfinder build project – March 2022
As a quick recap on my Pathfinder dinghy build project i stopped main work at the end of October last year with the hull fully planked, most of the interior epoxy coated and partially primed and with more of the internal structure going in – seat/locker tops and such like. I stopped work simply because it was getting too cold and damp to work with epoxy resin and also because we couldn’t get a dry slot in the weather to go get more materials from the marine timber merchant : aside from that i felt like i would benefit from a break and needed to get other work done around the place.
Last week, as i write, i spent two days slowly lifting the hull off it’s building frame, suspending it and then heaving it over such that it’s now back on it’s building frame but upside down – the next stage being to fair, fill and glass coat all of the plank joints and ultimately the whole hull. While the hull is upside down i’ll also be making and fitting the skeg/s…..in discussion with John Welsford i might have a pair of skegs just like his SCAMP design – also, and outside the normal plans i fancy the idea of laminating and fitting an outer stem band to protect the bow and ‘chin’ of the hull.
For this post i just want to show the first sequence of jobs that i’m working on right now so….
- Bottom panel to first plank. On the Pathfinder design this joint is mainly made and supported by the wide and full length bilge/chine stringer (75 x 20mm timber) which runs the full length of the boat and which i first glued to the inside edge of the bottom panel and then made my first ever rolling bevel to accept the first plank. https://dirtywetdog.co.uk/2021/09/20/what-the-stringer-did-next/
- On the outside this then leaves a long open gap between the bottom panel and first plank which also has to become a strong joint and of course filled and faired. For the first one of the pair i made a bit of a mistake in that i tried to fair the edges of the gap with a plane and sander first and then filled the joint with epoxy resin and high density filler. That created a bit of a flat and hollow as the filler and glue slumped into the join…..that needed an over-fill to make the joint look fair. On the opposite side i filled first but before i even did that i brushed neat glue into the vee of the joint first to stop so much glue being pulled out of the filler mix. As of today both sides are now filled and faired and are waiting for a line of glass tape but once again it’s too cold here for that job.
- Job 2, lapstrake plank edge joints. With the next 3 planks up from the first one there is a lapstrake ‘step’ where each plank sits over the edge of the plank below it and where both plank edges are joined together and onto the underlying stringer. While i tried to get fair plank edges i found that my lack of expertise left an ugly stepped hull panel line which really spoils the lines of the hull. My solution has been to make a long wooden batten out of a length of 20 x 20mm timber, drilled out every 250mm and to screw that temporarily to near the plank edge and let that find a fair curve around the hull. The best tools iv’e found to then fair that edge have been my rebate plane, my Japanese saw-rasp and then a wooden block and a length of 40 grit sandpaper.
Most noticeable on the second plank edge is that there is another ‘vee’ that needs filling and fairing as it contributes to the plank/plank strength – as per the design instructions i did a fill with high density filler and created a smooth fillet there and i also rounded the finished plank edges to one day take a run of glass tape. All the plank edges that iv’e worked on so far need a bit of sanding and fairing yet – plus lots of screws to back out and fill the holes but the whole hull is slowly looking a lot better…..’sharper’ somehow.
Warm the bed !
I said earlier that i left off main work until the beginning of March and slightly higher day temperatures – ideally above 10 degrees ; well, it’s done that this week but there’s still been a cold wind dropping the actual surface and joint temperature so iv’e brought into play a new version of an old joint warming technique. Just as an experiment i ran first the space heater and then the hot air gun under the hull to create a warm air bubble inside the hull – not stunningly effective as most of the heat is just lost ; so today i made up a warming quilt using an electric blanket, an old single quilt and even older quilt cover. The whole thing goes over all 3 joints for about 6 feet with the quilt uppermost to hold the heat in and the whole thing sits on top of a plastic sheet so the whole thing can go over just gelled epoxy – i find all it needs is to set maximum heat for an hour on the timer and the epoxy filler cures fully.