CS23 Build Config: Open Deck / Closed Transom

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TomW1
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Re: CS23 Build Config: Open Deck / Closed Transom

Post by TomW1 »

You are correct do not go by what the gaps are in the inside at this point, when you add the frame for the final time you will cut off the 3 points so that they fit better. You want the outside to have a fair and neat curvature at this point. Make it look pretty on the outside. :D

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

rsiedl
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Re: CS23 Build Config: Open Deck / Closed Transom

Post by rsiedl »

I've run into my next issue :)

I'm having trouble with getting the chine step right. The bow and stern section of the chine fit great but the middle section seems to be a different curve to the hull.

Stern section of the chine step:

Image

Bow section of the chine step:

Image

The middle section of the chine step:

Image

Image

I've checked twice against the plan and it does match up.

Image

I can go and modify it to suit but I'm worried if I do that, I might run into problems down the road. I would prefer to know where I've gone wrong and try to rectify that.

The discrepancy is the same on the port and starboard side.

Could anyone suggest where I should be investigating to identify the cause?

Cheers.
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rsiedl
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Re: CS23 Build Config: Open Deck / Closed Transom

Post by rsiedl »

I went ahead and cut a piece to fit and it looks a lot better now.

Image

A few measurements along the curve were definitely different, perhaps that is just due to the unique shape the hull panels take when being bent into shape?
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pee wee
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Re: CS23 Build Config: Open Deck / Closed Transom

Post by pee wee »

Hard to be sure, and you've already come up with a solution. It could be the hull panel is slightly off, but to me it looks like there's something slightly off about the curve of the chine strip at the gap; there's a nice curve leading in and out, but some waviness and a bit of a kink in that area . . or it could just be the photo. :lol: Build on! 8)

Image
Hank

rsiedl
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Re: CS23 Build Config: Open Deck / Closed Transom

Post by rsiedl »

Yeah, when I cut the second one I ignored one of the measurements (7,64) and focused more on letting the PVC pipe create the curve.

This meant the measurement I ignored was around 10mm "off" the curve I created, but it fit really well so I went with that.
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rsiedl
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Re: CS23 Build Config: Open Deck / Closed Transom

Post by rsiedl »

What size radius should I be aiming for on the chine step and transom?

I've read it should be sharp but also believe a non radius bend weakens the glass?

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bklake
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Re: CS23 Build Config: Open Deck / Closed Transom

Post by bklake »

I think you round it over to the correct radius, glass it, then built a sharp edge with filler. There are several topics on building sharp edges on the chine.

More experience builders will chime in with the correct radius and specifics.

pee wee
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Re: CS23 Build Config: Open Deck / Closed Transom

Post by pee wee »

It depends on what glass you're using, but 3/8" works for most cases, 1/2" is easier if your ply is thick enough to take it. Of course, sharpen it back up after the glass is done.
Hank

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Re: CS23 Build Config: Open Deck / Closed Transom

Post by Dan_Smullen »

Is cool to see another one of these come together.

Specs call for 9mm or 12mm material for the hull?

TomW1
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Re: CS23 Build Config: Open Deck / Closed Transom

Post by TomW1 »

Right now for glassing you need a 3/8"-1/2" curve on the edges for the 12oz fiberglass to take the curve. It will not take a sharp bend, so round any edges to 3/8" at this point. Then go back and make a sharp edge at the transom and on the sides where you will be on plane. Make a mix of epoxy, cabosil and wood flour, build a dam of cheap ply where you are building up the edge, tack it in place, and you will get a nice sharp edge. Hope I have been clear ask any questions if you have any. This is just for the where the side and transom meet the hull. The hull seams should be smooth, before taping.

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

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