Sometimes the OEM plans the hardware installation and embeds backing plates or simply solid fiberglass of the appropriate thickness. A backer is used to prevent crushing the core and to support lateral loads. Solid fiberglass won't crush and a sufficiently large washer nut bolts at the appropriate torque will maximize lateral support as long as the foundation is solid and not flexing. All questions which cannot be answered without on site evaluation.
Consider using FRP board in 1/4" or 1/2" available from McMaster-Carr or G10 board available from marine stores. Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD On Feb 23, 2018 12:48 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
