Marshall's FS17

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MarshallTX
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Re: Marshall's FS17

Post by MarshallTX »

Gentlemen - I'm confused on where the side panels match-up with the transom. If I leave as is, then I have a portion of the transom edge exposed. If I alter how the transom and the side panels mate to completely cover the edge of the transom, then the side panels will be above the the top-line of the transom (VERY crude image attached). To me it's a geometry problem since the transom is at an angle and the side panels are not. Honestly, I think I'm missing something.
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Transom Protusion1.jpg
Transom Protusion1.jpg (55.01 KiB) Viewed 1261 times

TomW1
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Re: Marshall's FS17

Post by TomW1 »

Remember when you mate the side panel to the edge of the transom it will have the same angle as the transom and will be the same size. Measure the length of the transom and the length of the side to see if I am not right. If not then one of them was cut wrong, as the side should cover the transom edge. Maybe some one who has built an FS17 can give you a better answer, but that is what I think it is for now.

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

narfi
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Re: Marshall's FS17

Post by narfi »

Not really awake yet but I'll try to look at the plans and my log for memory later today.... I think the transom is supposed to be set by motor well panels and not the side panels, but I might be remembering wrong. I vaguely remember having some questions at that stage as well.

fallguy1000
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Re: Marshall's FS17

Post by fallguy1000 »

You are developing the sheer. In stitch n glue or foam boat builds, the sheer has to be adjusted at the transom or the transom adjusted to the sheer.

I find adjusting the transom silly and to me it looks odd because the engine powerhead and the transom top are not on the same angle.

I would make the sheer match the transom top. And I would not plane and sand off the transom. I like them to be angled.

You will just need to raise the sheer with the rubrail to meet the forward edge of the transom and put a little bend in the end to make it match. The purple is a rubrail; disregard the forward size discrepancy of the drawing. All that matters is the transom.
F2C530EB-0EDD-49A7-912A-97AAC5295EAB.jpeg
F2C530EB-0EDD-49A7-912A-97AAC5295EAB.jpeg (90.28 KiB) Viewed 1219 times
My boat build is here -------->

viewtopic.php?f=12&t=62495

fallguy1000
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Re: Marshall's FS17

Post by fallguy1000 »

Here is an extreme example of adjusting the transom to the sheer where they have no choice.
58E3850B-B1FE-41CB-AAF5-38CC4C5F36EF.jpeg
58E3850B-B1FE-41CB-AAF5-38CC4C5F36EF.jpeg (59.63 KiB) Viewed 1213 times
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VT_Jeff
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Re: Marshall's FS17

Post by VT_Jeff »

MarshallTX wrote: Tue Nov 16, 2021 9:34 pm Honestly, I think I'm missing something.
Possible but I suspect not. As has been pointed out, the transom top and the sheerline are in different planes so there's no one-size-fits-all way to join them without them still being in different planes. The right answer for you depends, I think, on your ultimate plan for rubrails/aft deck/motor well/etc and how all those things will tie together. The same issue normally exists between the transom bottom and the bottom panels, where some choose to plane the transom bottom "flat" and some choose to fill the gap. And then the same issue exists where the deck meets the sheer: there will be a small gap the length of the sheer unless you choose to plane the sheer "flat" in that plane. I planed my sheer flat to meet the deck, poorly, and then ended up filling a larger gap than if I had just gap-filled originally.

As has been pointed out also, keep in mind that this is a wood-cored boat, not a wood boat, and the wood parts are not meant to be joined in the traditional sense: composite material is used to bridge the gaps and form many/most/all of the transitions.
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MarshallTX
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Re: Marshall's FS17

Post by MarshallTX »

All inputs greatly appreciated. My feeling is that the angle of the transom creates some unusual geometry where it mates to the side panels. There seems to be a natural fit that results in a small protrusion of the transom above the side panels. For now, I'm willing to accept during this phase. Get ready for questions on a solution as I get to glassing and rub-rail installation! Again, many thanks...

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Re: Marshall's FS17

Post by narfi »

Ok, its been a while but my memory was right, the transom angle is set by the motorwell sides in the jig,
The transom is part of your jig.
Screenshot 2021-11-17 100103.PNG.jpg
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Screenshot 2021-11-17 101006.jpg
Screenshot 2021-11-17 101006.jpg (38.33 KiB) Viewed 1187 times
Here are some of my pictures doing it,

The jig with motorwell sides setting the angle,
20171230_213519.jpg
20171230_213519.jpg (91.41 KiB) Viewed 1187 times
Starting to tie up all the parts over the jig, the transom and stringers are set, the side and bottom panels can slide fore and aft for best fit, any overhang is sanded off, any underhang? is filled with woodflour/epoxy. I do remember that the side panels were not straight with the transom, but it was set by the motorwell sides.
20180101_211005.jpg
20180101_211005.jpg (45.07 KiB) Viewed 1187 times
Here you can see just how much filler I used before rounding the corners for taping and glassing.
20180107_215457.jpg
20180107_215457.jpg (46.18 KiB) Viewed 1187 times
Even when done it wasn't perfect, you can see one side sits higher on the transom than the other, I fixed that all with sanding/filling/planing and covering with the gunwalls and rubrails.
20180614_214214.jpg
20180614_214214.jpg (77.35 KiB) Viewed 1187 times
If I learned anything during the process, it was that nothing needs to be perfect, you can fill and sand anything to look nice later.

I think right now the most critical thing is making sure your bottom panels are straight and have no hook or rocker.

TomW1
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Re: Marshall's FS17

Post by TomW1 »

Good exlanation Narfi. Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

fallguy1000
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Re: Marshall's FS17

Post by fallguy1000 »

MarshallTX wrote: Wed Nov 17, 2021 11:34 am All inputs greatly appreciated. My feeling is that the angle of the transom creates some unusual geometry where it mates to the side panels. There seems to be a natural fit that results in a small protrusion of the transom above the side panels. For now, I'm willing to accept during this phase. Get ready for questions on a solution as I get to glassing and rub-rail installation! Again, many thanks...
Just make nothing higher than the transom roght side up. It'll be great and water won't stand on it.
My boat build is here -------->

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