28 BERTRAM OUTBOARD CONVERSION

Questions about boat repairs with our resins and fiberglass: hull patches, transoms and stringers, foam, rot etc.
doug42190
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Re: 28 BERTRAM OUTBOARD CONVERSION

Post by doug42190 » Mon Dec 25, 2017 2:33 pm

DAYTRIP and topwater;
Than you both for the description of your transom rigs to flip a boat. I understood yours perfectly DAYTRIP and the picture of yours topwater was worth a thousand words. I can weld something like that up no problem. What was the thickness? I am guessing 1/4 inch to 5/16 for the plate and about 3" for the pipe?
Merry Christmas.
Doug



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Re: 28 BERTRAM OUTBOARD CONVERSION

Post by DAYTRIP » Mon Dec 25, 2017 3:55 pm

I like topwaters trunnion better. One thing that I remember now is we had multiple holes for shackles so we could get them below the horizontal CG. Other wise it is working against the hull weight to get her to roll. Right on the CG would be ideal but I think there is more art then science.

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Re: 28 BERTRAM OUTBOARD CONVERSION

Post by topwater » Tue Dec 26, 2017 8:34 am

Doug it is just some 1/4" plate welded up. Like daytrip said i tried to line it up so it would flip over by itself
when it got to the tipping point which it did.
Novi 23 finally launched !

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Re: 28 BERTRAM OUTBOARD CONVERSION

Post by DAYTRIP » Wed Jan 10, 2018 9:54 pm

Glamour shot! Pulled it out to replace main oil seals on engines. Can see the ballast tank draining.



Image



Image
Last edited by DAYTRIP on Tue Jan 16, 2018 5:37 pm, edited 1 time in total.

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Re: 28 BERTRAM OUTBOARD CONVERSION

Post by Rickk » Fri Jan 12, 2018 7:14 pm

That's a lot of boat - very nice glamour shots of a nice boat.

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Re: 28 BERTRAM OUTBOARD CONVERSION

Post by Jeff » Fri Jan 12, 2018 7:37 pm

Very nice Daytrip!!! Great Boat!!! Jeff

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Re: 28 BERTRAM OUTBOARD CONVERSION

Post by DAYTRIP » Fri Jan 12, 2018 10:10 pm

Thanks fellas!

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Re: 28 BERTRAM OUTBOARD CONVERSION

Post by Fuzz » Sat Jan 13, 2018 12:36 am

Yes Sir that is one fine looking boat :!:

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Re: 28 BERTRAM OUTBOARD CONVERSION

Post by Rickk » Mon Jan 22, 2018 8:50 pm

Is there a formula (an easy one) that tells you how much virtual weight an engine set back on a bracket or lift, say 26", will add to the weight at the transom?
For example - I add a 26" porta bracket to my boat and I add a 550 lb engine to the bracket. What virtual weight is added to the transom?

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Re: 28 BERTRAM OUTBOARD CONVERSION

Post by DAYTRIP » Mon Jan 22, 2018 9:17 pm

The weight is the weight Rick. I think what you are calling virtual weight is moment that is created. So if you move the engine back 26” it creates a 550*26=14300lb-in or 1191 lb-ft moment. To balance this you add weight on the other side(forward) of the transom. The farther forward the less weight required. If you add weight 10’ forward you need to add 1191/10= 119.1lbs. that accheives balance at rest. To negate the affect while running you have to do the same thing based on the distance from the center of lift. Is that what you are driving at?

If you are thinking what twist you are putting on the transom it is the moment or 1191lb ft. With that you can figure out what thickness your transom needs to be. Maybe that is what you are looking for?

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