APPLE PIE DINGHY TENDER.
I build a stitch and glue plywood and fiberglass pram tender for my Tanzer 22.
At the end of day 4, I have back seat glued in and middle seat assembly glued. The interior has 2 coats of resin. The gunwales are ready to be applied. The boat feels quite stiff.
DAY 5 of building a plywood stitch and glue Apple Pie Dinghy tender for my Tanzer 22.
The Apple Pie weights about 65 pounds and was easy to turn over. It was also quite rigid. the green tape marks the 6 inch intervals used to draft the boat.
This photo is strictly for bragging. This shows the 2 holes I drilled from the interior to screw in the daggerboard assembly. They are perfectly centered on the exterior!!
I marked the position of the runners that help protect the bottom. Doing it before fiberglassing makes it easier because I can work on a sticky surface but it's hard to mark on one. I also marked the position of the skeg that will keep the boat going straight.
Taking a pattern for the skeg, here I'm working out the hull curvature. I think the bottom of the skeg should be parallel to the waterline. I wish I had marked it.
I made up a batch of epoxy thickened with wood flour and filled in the gaps in the seam. I also touched up any of the stitching wire holes.
The holes are a disadvantage of the stitch and glue boat-building method. In this case they won't show because the boat will be painted.
After lunch the epoxy had set enough to sand. I'm using medium hardener but it's a million degrees and in the sun and it sets very quickly. I used my trusty sander with a 60 grit disk and rounded all the edges. It's easier to apply fiberglass if the corners are not sharp. The disk was gummed up by the end but no problem.
The fiberglass cloth I'm using is 6 ounces. I have a seam down the middle across, not lengthwise. It's easier to measure this way I think. It worked really well. I cut off extra material and folded back one section.
The fiberglass cloth went down very well. It was much easier to do than the interior. I cut the cloth at the junction of the side and the transom and overlapped the cloth over the corner.
I also added another strip of fiberglass over the edge and corner to help protect them. This means I will have to sand and finish a bit more but it's extra insurance against being dragged on the ground.
The epoxy sits in an ice water bath. It was setting so quickly that I was afraid I would start loosing my batch. It worked very well but the last bit at the bottom was really stiff from the cold. It flowed as soon as it hit the warm boat.
As soon as I finished the first coat of epoxy over my little Apple Pie Tender I was able to go back to the beginning and apply a second coat. It was setting very quickly.
MAS epoxy does not blush so I did not worry about washing the hull between coats of epoxy.
I had cut the runner material over size and this was useful weighting them down as the epoxy thickened with silica set.
Since I have no screws in the runners I had to improvise weights. It's nice if the runners can be parallel to the centre line. It tracks better. I had made lines earlier and they showed through the epoxy and fiberglass cloth very well.
The skeg has been cut from the pattern and tested against the hull before I applied the fiberglass. The fit is good. I am lucky I have some old shelves that are douglas fir. They are a full inch unfinished and will sand to about seven eights inch thickness.
NOTE: After a couple of season of use I have noticed a slight warp in the skeg. I don't know if it's the choice of wood or if it is something I did.
Skeg has been glued to the bottom of the boat and a fillet applied to the side. This will allow a radius on the edge where I can put a strip of fiberglass to reinforce the skeg.
The skeg has been glued and reinforced. The skeg got a second coat of epoxy. I trimmed the extra fiberglass that was hanging over the edge. It's much easier to do when it is partially stiff and not hard. Finally I checked it for position and made sure it was square to the hull. Everything needs time to set and stiffen up. Because the runners are under tension I don't want to remove the weights until tomorrow. It's not a huge curve but why take a chance that they will spring up.
END OF DAY 5. Grasshopper is now fiberglassed on the outside, the skeg and runners are installed, there are 2 coats of resin on everything and the gunwales are ready to be applied.
Note: I was thinking about the runners and realized that they are useless at the back. The pressure would end up on the corner of the hull. The skeg is too high to allow the runner to touch the ground. I could not have placed this runner far enough to the edge to work. Either I need a much higher runner placed more to the edge , OR what is more practical, I need a second set of runners that protect the back corners but don't go all the way to the front. (They can't go all the way to the front because the bow is narrower than the stern.)
This web site reflects my personal ideas and doesn't represent anyone else's point of view.