Backing plates for stanchions

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48dodge

48dodge

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Oct 10, 2006
492
Oday 222 Mt. Pleasant, SC
I was wondering what materials should I use for a backing plate for some new stanchions I have. They have a slightly different bolt pattern than the bases they are replacing so the plates can't be reused. I would like something that looks OK, too. Would starboard be OK since it's not something that needs to be glued in place? If yes, then I'll probably go with cutting board plastic since it doesn't need to be UV protected. What are some of my options?
 
Ross

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
I used white oak finished bright. Remember that the holes in the deck are also not the same pattern and should be repaired.
 
48dodge

48dodge

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Oct 10, 2006
492
Oday 222 Mt. Pleasant, SC
All holes are going to be drilled out, core cleaned out, and filled prior to doing anything. I'll be using the same technique Maine Sail has on his site.
 
Ross

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
The backing plate just spreads the load and supports the nut and washer better than just the fiberglass could.
 
Joe11688

Joe11688

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Jan 24, 2005
4,881
Oday 222 Dighton, Ma.
I think that Starboard would crack near the holes if the stanchion ever received a sudden bang. Stainless steel would be best. Oak is good and also plywood.
Joe
 
Joe11688

Joe11688

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Jan 24, 2005
4,881
Oday 222 Dighton, Ma.
Hey Ross,
I'm beginning to load my boat food in my boat right now!
Joe
 
sailingdog

sailingdog

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Oct 22, 2008
3,502
- Telstar 28 Buzzards Bay
Oak isn't a good choice, as it can split. I'd highly recommend making your backing plates of fiberglass. Aluminum is another good choice. Stainless steel isn't a very good choice as it is very hard to work.
 
Ross

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
sailingdog said:
Oak isn't a good choice, as it can split. I'd highly recommend making your backing plates of fiberglass. Aluminum is another good choice. Stainless steel isn't a very good choice as it is very hard to work.
Click to expand
Inch and a quarter oak isn't gonna spilt in a 4x4 block. That's why they build chairs out of it.
 
Jumpstart

Jumpstart

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Jan 13, 2009
394
J Boat 92 78 Sandusky
G10 epoxy infused fiberglass plate. Looks like the stuff they make motherboards from. 1/4" thick from McMaster Carr or local plastic supply house. Doesn't crack, rot, compress, or have galvanic issues with your stainless fasteners. Cut and drill is easy. All the big boat racing campaigns I've been associated with use it. Easy to laminate to under side of deck id needed and can be painted.
 
Ross

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
But it will flex! The backing plates must be thick enough and stiff enough to distribute the load ove a large surface. Think of the stanchions as very fancy pry bars and the bolts as nails that you are trying to pull. You want the bolts to break or the stanchion to bend but you never want the deck to distort and break the seal formed by the bedding compound.
 
Jumpstart

Jumpstart

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Jan 13, 2009
394
J Boat 92 78 Sandusky
Ross, 1/4" is considerably thicker than motherboard material. 1/2" is available if you are really concerned but come on this is for a 22' boat. You might google the mechanical properties of G-10 and compare it to aluminum to see what I am getting at. This stuff is an epoxy plate and several times stronger than your deck.
 
Ross

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
I reinforced my deck. It is more than a quarter inch thick. Oak at the saw mill is a dollar per board foot.
 
Dan

Dan

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Jul 26, 2006
190
Hunter 420 Stamford
I'm wondering if the oak might rot over time without your knowing it (?). If you do use it, would it make sense to put a coat of epoxy over it to seal out moisture?
 
Ross

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
White oak is rated as durable. For a backing plate that should never get wet it will last as long as the boat.
 
sailingdog

sailingdog

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Oct 22, 2008
3,502
- Telstar 28 Buzzards Bay
The problem is that you can not guarantee that it won't get wet. :) Fiberglass doesn't care if it gets wet. :)
Ross said:
White oak is rated as durable. For a backing plate that should never get wet it will last as long as the boat.
Click to expand
 
Ross

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
sailingdog said:
The problem is that you can not guarantee that it won't get wet. :) Fiberglass doesn't care if it gets wet. :)
Click to expand
Sorta makes you wonder what they were thinking when they framed ships and pleasure boats with white oak and sheathed them with cedar.
 
sailingdog

sailingdog

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Oct 22, 2008
3,502
- Telstar 28 Buzzards Bay
Wooden boats are a different kettle of fish entirely. :D
Ross said:
Sorta makes you wonder what they were thinking when they framed ships and pleasure boats with white oak and sheathed them with cedar.
Click to expand
 
R

RacerX

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Oct 20, 2008
10
ODay 23 Chesapeake
48dodge,

Just did that yesterday, I had one loose stanchion and wanted a different backing plate. Had some extra starboard so was able to cut it to fit with about 4-5 test fits. It is a nice piece with alot of area. I can't see it fracturing since its flush with the underside of the deck, and has washers on the nut-side to distribute any force, as well as no cuts. Try working with it, I mean breaking a 1'x1' piece. A smaller piece with be tougher to snap. The starboard I used is 1/2 I think, so should be pretty tough.
 
Ross

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
RacerX said:
48dodge,

Just did that yesterday, I had one loose stanchion and wanted a different backing plate. Had some extra starboard so was able to cut it to fit with about 4-5 test fits. It is a nice piece with alot of area. I can't see it fracturing since its flush with the underside of the deck, and has washers on the nut-side to distribute any force, as well as no cuts. Try working with it, I mean breaking a 1'x1' piece. A smaller piece with be tougher to snap. The starboard I used is 1/2 I think, so should be pretty tough.
Click to expand
Racer , I don't wish to make you feel bad, but I doubt that you could break a foot square of half inch plywood. The reason they make pry bars is because we mortals aren't as strong as the materials we employ. I rather doubt that you could pull a 4d nail driven 3/4 inch deep in soft pine with just your bare fingers. It is an error to judge the suitability of a material by the way it feels in our hands. Check the tensile strength in the spec's, the flex characteristics, and the compressibility.
 
S

Steve Dion

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Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
What was used on the original backing plates? It's been good for 25 years, so you should be good for another 25 with the same material!
 
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