[Rhodes22-list] High thrust engine-transom

[ASNOOCH at aol.com]

Robert, 
 
The new motor lift maybe more helpful in managing the outboard, however  it's 
ability to further distribute sudden extreme outboard motor impact on too  
thin fibreglass that may surround the mount I would suspect will still yield an  
intact outboard motor fibreglass sandwich leaving that hole around that 
mount. I  believe that increasing the capacity/surface area of the backer plate/s 
will  significantly help without the exterior aluminum plate. I installed the 
exterior  aluminum plate due to my belief that much of the remaining transom 
glass was  thin and was filled with stress fractures following the "accident 
tearing free "  of the mount.
Burt
 
 
 
In a message dated 9/23/2007 11:14:00 P.M. Eastern Daylight Time,  
robert at squirrelhaven.com writes:

Thanks  for the info, Burt.  That helps a lot.

I suspect that the new  motor lift not only helps 
manage the motor, but also distributes the load  
over a larger area.  Stan's evolutionary 
engineering  again!

Did you paint the aluminum to match the  hull?

/Robert

ASNOOCH at aol.com wrote:
> 
> 
>  Robert, I would suggest that you consider Stan's recommendation to use  the
> minimal amt. of Hp to get up to hull speed... unless you consider  a beef 
up....
> 
> I will attempt in during the next few days to  take a stern photo....  
however
> she is dockside.... anode is  below water level...
> To control cost, weight and ease of  construction.... I placed the aluminum
> plate on the outside. It  covered the entire port half of the stern..and 
matches
>  it's  configuration. . It has been epoxy laminated to the stern and through
>  bolted. I selected standard marine circular center bolt sacrificial  
anodes.
> Two  were attached to the plate below the water  level.
> I felt it was additionally important to internally brace the  entire transom
> with marine laminated 1inch plywood braces to further  distribute any 
stress.
> Sure has provided a very comfortable  feeling...  I believe the engine  
thrust
> flexing is only a  mild indication of the relative strength of the transom  
to
>  stress....the force of my engine's weight sitting up and out of the   
water is
> the real "testor".  Now a heavier , 4 stroke  most  probably  would magnify 
the
> possible problem.... I'm surprised I  have not heard of this  occurring
> before.... perhaps I had an  especially thin fiberglass  transom...  Burt
> 
> In a  message dated 9/23/2007 9:30:43 P.M. Eastern Daylight Time,
>  robert at squirrelhaven.com writes:
> 
> ASNOOCH at aol.com  wrote:
> > ... My fibreglass repair brought
> >   the  thickness up to over 1/2 inch, plus
> > more than double  the  backing. On the
> > outside  of the stern, was cut a  1/4 inch
> >  aluminum plate in the shape of the
> >  stern, to  which I attached  sacrificial
> > metal plates ,  and both epoxy and bolted
> > the  plate  to the  stern...
> 
> I too have a little flex in my stern by my   motor mount,
> so some questions, if you please:
> 
>  Aluminum plate on  the OUTSIDE of the stern?
> 
> How big,  what shape, where  mounted?
> 
> Bolted thru to a plate on  the inside?
> 
> Where, what kind  of sacrificial  plate?
> 
> Any pictures?
> 
> Thanks for any   info/help!
> 
> /Robert







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