Motorwell on Sweet Caroline

Questions about modifying a design

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parsj1957
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Location: San Francisco Bay Area

Motorwell on Sweet Caroline

Post by parsj1957 »

I have two prime candidates for an outboard motor for my Sweet Caroline project which I just started. The 40hp Mercury SeaPro which comes with a 20" shaft, or the 40hp Mercury Fourstroke EFI which (this year) can come in a 15" shaft. The 15" shaft is what the plans specify, and it would weigh ~204lbs.
There is a modification to raise the motor well 5" for a 20" shaft - which weighs 260lbs. I plan to have a center console remote steering.

So now my questions:
1) I like the longterm reliability of the SeaPro (and salt water designed) but is the extra weight an issue?
2) Is the extra size an issue beside 'hitting' the thwart as warned in the plans?
3) I plan to use this in the Sf Bay, Delta, and local lakes -- so especially on the Bay (and occasionally on the Delta) waves are an issue. Would the 5" of extra height for the 20" be an advantage in 'blocking' following seas from swamping into the boat?

Has anyone ever transom mounted the engine on the Sweet Caroline, and then just had a self-bailing well across the back to help with any 'swamping' issues?

Thanks for any help -- woods all milled - frames, keel and stem starts tomorrow so transom decisions coming up soon.
J.

hoodman
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Re: Motorwell on Sweet Caroline

Post by hoodman »

Wow, the fact that you can get a new 40hp with a 15" shaft is a huge plus. And really lightweight too. It might even be a good option for Zip builders out there (on which a 20" shaft motor tends to look comically large). I'd go with size and weight as the most important factors. With the 15" shaft you could build as intended without modifications.
Matt

Building a Geronimo......!
viewtopic.php?f=2&t=25139

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parsj1957
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Location: San Francisco Bay Area

Re: Motorwell on Sweet Caroline

Post by parsj1957 »

hoodman wrote:
Tue Mar 24, 2020 5:10 pm
Wow, the fact that you can get a new 40hp with a 15" shaft is a huge plus. And really lightweight too. It might even be a good option for Zip builders out there (on which a 20" shaft motor tends to look comically large). I'd go with size and weight as the most important factors. With the 15" shaft you could build as intended without modifications.
I agree an extra ~50ish pounds plus heavier transom is a big weight shift/add -- but curious if folks have experience with swamping that would compensate for this negative?.
I've always been a sailor -- my first / previous build was a 20' gaff rigged sailboat so I'm a newbie with respect to some of the motor boat/ lower profile issues that may arise -- last time I was in a small motor boat was probably fishing with my dad as a teenager -- and that was more than a couple of years ago.
J.

hoodman
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Location: Lafayette, IN

Re: Motorwell on Sweet Caroline

Post by hoodman »

I don't have any experience in a motorboat with a well-mounted engine. But it seems like the transom would kill most of the water that would want to come aboard with following swells.
Matt

Building a Geronimo......!
viewtopic.php?f=2&t=25139

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parsj1957
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Location: San Francisco Bay Area

Re: Motorwell on Sweet Caroline

Post by parsj1957 »

Started framing up the transom the last couple of days, and have to admit I was being stupid and looking at this 'upside' down. In my mind I was looking at the motor well the same way you would a standard transom - longer shaft, less cut out to 'reach' and hence better rear 'coverage'. The motor well is the opposite - a larger motor requires a bigger cut out - and it is 'on the bottom' -- the transom still is 'full' over the top of the motor well - so the smaller engine implies a smaller opening --- boy do I feel dense -- but at least now I have the boat and motor well 'rightside up' in my brain...

J.
J.

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parsj1957
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Location: San Francisco Bay Area

Re: Motorwell on Sweet Caroline

Post by parsj1957 »

IMG_1756.jpg
Wanted to share proof that I did finally get my brain to work right. Here's the motor well all made up and ready to take back apart, prep for glueing and install/glue in place piece by piece. Had thought about increasing the angle on the motor mount, but then realized that would have shortened the overall length of the box, making the motor fit tighter and perhaps limiting the amount of lift/tilt available so I stayed with the recommended 12 degrees.
J.

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