New Backing Plates

mixmkr

Active Member
Thread starter #1
Although I did add some cockpit inspection ports to my '69 Sunfish, I didn't want to add any on the deck. Instead I cut access on the hull bottom and epoxied with West Systems...some 1/4" aluminum plates to the underside of the deck. Then I was able to screw and tap the hardware on, never having to worry about the old wood blocks failing again. Plus the aluminum was able to spread out the "load" better. Then, just glassed up the bottom. Anyone do this and was I crazy? I thought it was a great idea actually. The pictures don't show...but I finished off fairing the glass work and then gelcoat. SInce I beach the boat often and scratch the bottom, I wasn't too concerned about the bottomsides that much either, even though the final glassing came out great.
 

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L&VW

Well-Known Member
#3
Since I beach the boat often and scratch the bottom, I wasn't too concerned about the bottomsides that much either, even though the final glassing came out great.
A good, stronger, process for those of us who already have two wrongly-placed inspection ports in the deck. :confused:

If, instead of circles, you had cut out ovals, they could have been used in the repair.

Offset the ovals a few degrees, taper the contacting edges, bond those edges inside the hole, and fill the rest with layers of overlapping fiberglass cloth (with 45º offsets). The use of West System's colloidal silica (among other fillers) would assist in smoothing and fairing the repair.
Micro-ball additive / for resin - 407 LOW DENSITY - West System
 
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mixmkr

Active Member
Thread starter #4
I used minimal fairing since the hull is so thin. I DID use my old cutouts as a starting point just slightly offset
 

L&VW

Well-Known Member
#5
Although I did add some cockpit inspection ports to my '69 Sunfish, I didn't want to add any on the deck. Instead I cut access on the hull bottom and epoxied with West Systems...some 1/4" aluminum plates to the underside of the deck. Then I was able to screw and tap the hardware on, never having to worry about the old wood blocks failing again. Plus the aluminum was able to spread out the "load" better. Then, just glassed up the bottom. Anyone do this and was I crazy? I thought it was a great idea actually. The pictures don't show...but I finished off fairing the glass work and then gelcoat. SInce I beach the boat often and scratch the bottom, I wasn't too concerned about the bottomsides that much either, even though the final glassing came out great.
An early mention of TREX™ "wood" being used as backing for hardware is an alternative to "dissimilar metals" corrosion in saltwater use:

Odd looking Sunfish | SailingForums.com
 

mixmkr

Active Member
Thread starter #6
Yeah... I like threaded, tapped holes best most of the time. I think if things are still caulked properly, galvanic corrosion still shouldn't happen. IOW still bed the hardware really good. But manufactured lumber, the white or black "starboard"...etc. They'd all be good solutions too as you mention.
 
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