Backing Plate

T

Tug

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C Dory Year
1985
C Dory Model
22 Angler
Hull Identification Number
DOR22241H585
Vessel Name
Drifter
Have a question...do i need to put a backing plate...either on or under the deck when i install my windlass......

What size/type screws do you use for the anchor drain pipe clam shell....Thanks Tug
 
In my view backing plates are always a good thing, especially in high stress locations such as under the windlass or the bow cleat. Rather than use high cost materials like starboard, we just get thick cutting boards from Walmart and drill/cut them to shape. We always put large fender washers between them and the nuts. They don't corrode, are widely available and are cheap.
 
I would think that the reason for a backing plate is to distribute the force over a larger surface area. Hence, I'm a bit confused by the use of starboard or cutting boards for this purpose. I'd use either a stainless or aluminum plate.
 
I have lots of 1/4 inch Aluminum plate....i will use that...it is not too thick and is strong enough to distribute the weight. Thanks Tug
 
Roger,

I haven't done the force calculations but a 4x6x3/8 inch piece of cutting board is about as rigid as the same in aluminum and should yield the same in terms of surface area to distribute pressure, plus it won't corrode. When you consider that cleats and such are usually backed only with a fender washer it is, I think, a big improvement. I also like that it is cheap, easily formed, and readily available.
 
Tug, for an already cut aluminum backing plate, put the "Performance plate" under the deck, then use the supplied fender washers.
 
colobear":iel6grzv said:
Roger,

I haven't done the force calculations but a 4x6x3/8 inch piece of cutting board is about as rigid as the same in aluminum and should yield the same in terms of surface area to distribute pressure, plus it won't corrode. When you consider that cleats and such are usually backed only with a fender washer it is, I think, a big improvement. I also like that it is cheap, easily formed, and readily available.
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My experience with starboard is that it's quite compressible and cracks rather easily under stress. Hence I would think that it wouldn't make a good backing plate. Then again, I haven't done any calculations or looked up any material properties. Just flying by my engineering seat of the pants.
 
Back in the days when the factory was in Kent, I decided to get a new EZ loader trailer. So they told me to back into one of their bays with the boat on the old trailer. Next, they moved their hoist over the boat with three cables, one to the bow cleat and the other two to the aft cleats.

Next they lifted the boat off the trailer, pulled away the old trailer and wheeled the new one under the boat. I have to admit to great apprehension watching this whole process - with the boat and engine dangling there four feet above the concrete floor for a few minutes. But they slowly settled the boat down, checked for placement, and that was that.

Fender washers for the through bolts distribute the weight nicely. I anticipated hearing creaks and groans when this happened, but heard nothing. These boats are beefed up in the stress areas to handle loads. I believe the fender washers under the cleats are adequate for any winch
you would use.

John
 
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