Convex transom???

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greyrfox
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Convex transom???

Post by greyrfox »

I have been flitting around here and there looking at boat designs. I am strongly considering doing a Coronado in the fully stretch length (28-3"). I saw on the Nexus site that they have a design that has a convex transom that is in wood and finished beautifully. I am however wanting to use an I/O out-drive unit instead of a V-drive. Is that possible or is it a engineering nightmare waiting to happen? Let me know your thoughts on that one. It would be a unique look for sure. I am not sure if it would present any performance problems. It would seem to me that there would be a bit less drag than a normal flat one but that is just my uneducated (nautically speaking) and inexperienced mind at work!

The pic I saw was on the 9th picture. Check out the site. http://www.nexusmarine.com/odysy_exteriors.html

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Bill Edmundson
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Re: Convex transom???

Post by Bill Edmundson »

greyfox

You could build the standard transom as high as needed to mount the I/O. Then build the curved false transom on either side and above it.

I have a convex transom. I'm inboard. But. there is a picture in my link than shows how you might do it.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
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slug
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Re: Convex transom???

Post by slug »

Actually if you look at that photo, you can't tell if in fact ( tho we know different ) that there isn't an I/O unit UNDERNEATH the swim platform. This could be a solution? Curved transom above the platform, flat below.

Doug

greyrfox
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Re: Convex transom???

Post by greyrfox »

Bill: Yes I see that possibility. I was thinking that the transom could be laid up from thinner ply cores laid up on a form to maintain a convex from side to side. I am not sure how it would look with the transom being on a angle tucked in from top to bottom and curved side to side. I am interpreting what you meant as the transom above being vertical above the boot? I am also taking what your are saying is you would need a flat spot for the boot to sit on and I do not see that being a big deal. I am only talking about the back of the transom being curved and not the sides like the Nexus is done in a slight "barrelback" fashion (however that is cool looking). If I was to have a "bent" transom, I would only have a curved topside and leave the bottomside of the transom still flat but still finished like the top. Do you see any performance issues with that idea? Sometimes I fear that my hairbrain ideas will get me into trouble. :oops:
BTW Bill, That is one beautiful vessel you have built. I salivate when I look at your pics. (your boat I'm talkin about) :lol:

Slug: I thought the same thing however if you research the site, you will see that it is a prop under the keel with a rudder. But I do think it could work with a I/O unit myself. I think the look is outstanding.

Rick

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Bill Edmundson
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Re: Convex transom???

Post by Bill Edmundson »

Rick

Thanks.

What I wanted you to see was the arched frames on top of the flat transom. That can be used regardless of which way the "hard transom slopes.

Bill

BTW: That was a screw up. I placed one of the frames where the exaust needed ot be and had to move it.
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
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greyrfox
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Re: Convex transom???

Post by greyrfox »

Yeah I see that. You're talking about the curved top of the transom right. I also see that it is cupped from side to side. I see the top edge of the transom, where the rear carling would mount, (not sure if that is the correct term) is cut on a curve on the outside and left straight on the inside of that framework. Of course in my application the transom would be leaning out instead of in. I don't see a problem of a flat spot right where the boot bellows would need to be mounted.

If I was to have about a 3" bow in the sight of line from side to side across the transom, do you see that as being a negative issue in terms of the "planing" ability of the bottom as the crisp edge where the bottom meets the transom would not be a straight line but with a curvature? Secondly if I ended up using trim tabs would the tabs need to be mounted "in line with each other, perpendicular to the center line, instead of just right on the curved transom. Like using a wedge for them like you did for the exhaust flange? See what I mean?

Am I seeing that right?
Rick

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Bill Edmundson
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Re: Convex transom???

Post by Bill Edmundson »

Rick

I don't see a problem as long as the bottom has a crisp edge with the transom. I'm not home right now. I'll try to post some pictures of a pretty different planing transom soon.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
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