I think a backing plate is needed.

I would use G-10 or make my own fiberglass backing plate because I have the 
material.

Another option if you don't have anything;  Azek.  Pick a short length of 1 x 4 
trim.  It's easy to cut, waterproof, no painting or sealing required.  It's 
white and it's light.  Cuts like pine.  Add some fender washers to all the 
fasteners and you can really spread the load well.  


Word to the wise:

All horizontal surfaces on my boat are cored, yours may be solid glass, maybe 
not, so be ready to deal with that in the normal manner.   You determine the 
final location for the hardware and mark it.  Then you overbore the hole to at 
least twice the fastener size.  If you use 1/4" drill holes to 1/2" or if your 
using 5/16" fasteners drill holes to 5/8", or even larger, fill these holes 
with an initial layer of clear epoxy then epoxy and filler like West Systems 
404 high density filler.  I simply put heavy duty clear mailing tape underneath 
the hole and fill from above using whatever I have to remove bubbles, Q-tips 
work well for this.   The idea is to create an epoxy sleeve through the deck to 
seal the balsa core, bond the two skins, and also prevent the fasteners 
crushing the deck.   That's why I use 404. 



Chuck
Resolute
1990 C&C 34R
Broad Creek, Magothy River, Md

> On February 23, 2018 at 12:47 PM Jeremy Ralph via CnC-List 
> <cnc-list@cnc-list.com> wrote:
> 
>     Hi All,
> 
>     I'm installing a downrigger to catch big salmon.  There is an existing 
> aluminum plate aft of the spinnaker winch that I'm removing and replacing 
> with a larger one.  I plan to use the same hole pattern so I don't need to 
> drill new holes.  The original plate had no backing on the underside. Not 
> sure what it's purpose was. 
> 
>     Looking for some input:
>     1. Is a backing plate needed?  The nearby winches don't have any backing 
> other than washers.
>     2. what should I use as the backing plate?  Marine plywood?  Would normal 
> plywood be okay?  Getting aluminum made to exactly fit there would be a 
> challenge I think.  With wood I could craft it at the boat for an exact fit.  
>  
> 
>     Some links to pics:
>     Original plate from top: https://flic.kr/p/24BK3KM
>     Backing/underside: https://flic.kr/p/Gu1cqL
>     Nearby Winch underside w/o backing plate: https://flic.kr/p/EXCp5P
> 
>     Thanks,
> 
>     Jeremy
>      C&C 34-1 #041 
>       Vancouver BC
> 
> 
> 
>     _______________________________________________
> 
>     Thanks everyone for supporting this list with your contributions. Each 
> and every one is greatly appreciated. If you want to support the list - use 
> PayPal to send contribution -- https://www.paypal.me/stumurray
> 
> 
_______________________________________________

Thanks everyone for supporting this list with your contributions.  Each and 
every one is greatly appreciated.  If you want to support the list - use PayPal 
to send contribution --   https://www.paypal.me/stumurray

Reply via email to