Transom height and angle? How to measure?

[CAnderson]

My son and I are working on two Sunfish conversions and need to make the transom for each boat. How do I measure the transom angle?

The goal is to use a 2-5hp 2-cycle short shaft engine. Or perhaps an electric trolling motor with the battery mounted in the front.

Based on pictures, it looks like the transom angle should be leaned back away from the boat, where the top edge of the transom should be farther back than the bottom edge of the transom. Is this correct? Is the angle measured in relation to the bottom of the hull?

For a short shaft engine (I think that is 15" right) is it simply 15" from the top edge of the transom to the bottom of the hull?

Third, how thick should the transom be to accomodate clamping on a little engine like this? I was thinking of building the transom out of 3/4" plywood and then adding in a second rectangular piece where the engine is clamped or bolted on. In my thinking, this will make the transom 1 1/2" thick. Is that appropriate?

Thanks for any help you guys can offer. First project. Learning as we go.

cja

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[Tom Ayers]

15in. from the bottom of hull to top of the transom. angle back at 15 degrees from the bottom of hull. 1.5in. thick is good.

 

[CAnderson]

Tom-

Thanks for the quick reply. Now, if only I had an indoor workshop at the house and it wasn't preparing to thunderstorm! Although, I do love a good east coast summer thunderstorm.

cja
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[John D.]

15in. from the bottom of hull to top of the transom. angle back at 15 degrees from the bottom of hull. 1.5in. thick is good.






That's it. Don't measure the length of the transom. I.e. the length of the board used to make it. Measure on a vertical plane from bottom of boat to top of transom. The height the engine will be held out of the water. And every transom everywhere is 1 1/2 thick.

 

[Chris S.]

Here are some pictures of the motorboard on my BBSB I rebuilt last summer. It is on a 15 degree angle and should be 15 inches high from the bottom. Somehow I messed this up. I ended up with a hight of 13 3/4. I had to shim my motor up for this past season. In the next few weeks I will be taking this one off and putting a new one on. I would reccomend making it an inch higher then you need then trim it down to the exact spot. It seams some motors are a little differant. My old merc sat lower then my new OMC. Hope the pics help. Good luck with the build.
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