Re: Trailering with Outboard on Transom

From: Eric Johnson (etj@nwlink.com)
Date: Wed Feb 09 2000 - 01:20:03 PST


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        West Wight Potter Mailing List maintainer
                dfarrell@ridgecrest.ca.us
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>A 4hp motor has roughly 200 pounds of thrust. This force is directed normal

>to the surface of the transom, in this mode the transom is the weakest.
>Trailering a 50 lb motor puts the forces mostly in shear on the transom. In

>this mode the transom is the strongest. For concerns about moment forces,

>when the motor is down propelling the boat this has a much greater moment

>than when the motor is raised in the trailing position (400 ft lbs vs 50 ft

>lbs roughly). If you are concerned about the transom when trailering you
>should also be more concerned about the transom when motoring the boat.

Statically, I agree. The problem is, i think, dynamically, when you hit potholes
at speed or other bumpiness in the road. then the math gets a little more complicated,
the forces get higher, and my understanding is that people on this list have
actually damaged their transoms this way. I bring this up since so much of what
we talk about here in the winter is so hypothetical :) Its not a problem so
much on the water because, well, the water gives way. the suspension on the
trailer is much less compliant :)
http://www.nwlink.com



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