Trying to start on the project today, I discovered that my inside t-track upgrade has now become more involved/complicated than first investigated.
A few weeks ago, when I was still sluthing the upgrade, I posted some questions to Ask-All-Sailors about installing a T-track for jib sheeting on my 1980 36 Cherubini Hunter which for the last 36 years has relied on snap shackle sheeting on the aluminum toe rail. I received a lot of useful advice.
Then I went out and bought all the supplies.
Back to the "few weeks" ago time frame, I did drill into my deck, starting near the cabin top and then moving further away, a few 3/16" exploratory holes in the main deck. I noted that the plywood core section of the deck generally was about ~ 7" away from the cabin top. This equated to about the track being mounted 15"-16" inside the toe rail on average. Any closer to the cabin top and the drill only went through appx 1/4" - 3/16" single layer of FRP then into the void space between the upper deck FRP and the interior liner. No wood core underneath. I had hoped to mount the t-track closer to the cabin top, but still 15"-16" was a significant improvement compared to toe-rail sheeting. Certainly should've assisted sheeting for close-haul sailing.
Today I started drilling the holes for the track. To my surprise, the wood core in the deck in many spots was upwards 10" away from the cabin top. So in order to ensure that all the mounting holes would actually go through the core and then the lower FRP layer, I would be gaining only 10-12" more interior sheeting than the toe rail. Seems hardly worth the effort?
So, notwithstanding the single FRP layer, I am now considering to mount the t-track a much closer to the cabin top. To accomplish however, I am concerned that even with some thick fender washers below, the stresses from the jib sheet on the T-track will cause a lot of flexing = gelcoat crazing (at best) and/or = cracks in the FRP (at worse). And maybe the torquing/twisting from the sheet's tension will cause the cabin's side ports to begin to leak due to the the old caulk sealing the port frames flexing more than it's 36 year-old pedigree can handle.
The underneath void space close to the cabin top, between the interior liner and the deck's single layer of FRP is enough to install a backing plate of some sort the same 5' length of the T-track. My thought is to use a 3/4" x 2.5" piece of IPE which will be epoxy adhered to the underside of the single layer of FRP. Then 5/16" bolt through from the t-track above. IPE is incredibly rigid. And rot resistant in case of H20 ingress. I would think IPE might be more rigid than say a few layers of new FRP that I might try to wet out from underneath. (And a lot easier to do as well!)
I have posted some pictures of the interior liner near the gunwale so any interested respondents can get a feeling of my boat's layout. The blue tape is where I would need to mount for a full plywood core location. Too close to the toe rail to be much of an improvement. The red tape is through the deck's single layer of FRP near the cabin top.
I would cut a 5 feet by 2" rectangular slot in the liner so that I could insert the IPE piece. The liner at this location does not seem to be anything "structural" to the boat.
Last I would cover the raw opening with a decorative something.
Thoughts/considerations?
Many thanks for your interest.
A few weeks ago, when I was still sluthing the upgrade, I posted some questions to Ask-All-Sailors about installing a T-track for jib sheeting on my 1980 36 Cherubini Hunter which for the last 36 years has relied on snap shackle sheeting on the aluminum toe rail. I received a lot of useful advice.
Then I went out and bought all the supplies.
Back to the "few weeks" ago time frame, I did drill into my deck, starting near the cabin top and then moving further away, a few 3/16" exploratory holes in the main deck. I noted that the plywood core section of the deck generally was about ~ 7" away from the cabin top. This equated to about the track being mounted 15"-16" inside the toe rail on average. Any closer to the cabin top and the drill only went through appx 1/4" - 3/16" single layer of FRP then into the void space between the upper deck FRP and the interior liner. No wood core underneath. I had hoped to mount the t-track closer to the cabin top, but still 15"-16" was a significant improvement compared to toe-rail sheeting. Certainly should've assisted sheeting for close-haul sailing.
Today I started drilling the holes for the track. To my surprise, the wood core in the deck in many spots was upwards 10" away from the cabin top. So in order to ensure that all the mounting holes would actually go through the core and then the lower FRP layer, I would be gaining only 10-12" more interior sheeting than the toe rail. Seems hardly worth the effort?
So, notwithstanding the single FRP layer, I am now considering to mount the t-track a much closer to the cabin top. To accomplish however, I am concerned that even with some thick fender washers below, the stresses from the jib sheet on the T-track will cause a lot of flexing = gelcoat crazing (at best) and/or = cracks in the FRP (at worse). And maybe the torquing/twisting from the sheet's tension will cause the cabin's side ports to begin to leak due to the the old caulk sealing the port frames flexing more than it's 36 year-old pedigree can handle.
The underneath void space close to the cabin top, between the interior liner and the deck's single layer of FRP is enough to install a backing plate of some sort the same 5' length of the T-track. My thought is to use a 3/4" x 2.5" piece of IPE which will be epoxy adhered to the underside of the single layer of FRP. Then 5/16" bolt through from the t-track above. IPE is incredibly rigid. And rot resistant in case of H20 ingress. I would think IPE might be more rigid than say a few layers of new FRP that I might try to wet out from underneath. (And a lot easier to do as well!)
I have posted some pictures of the interior liner near the gunwale so any interested respondents can get a feeling of my boat's layout. The blue tape is where I would need to mount for a full plywood core location. Too close to the toe rail to be much of an improvement. The red tape is through the deck's single layer of FRP near the cabin top.
I would cut a 5 feet by 2" rectangular slot in the liner so that I could insert the IPE piece. The liner at this location does not seem to be anything "structural" to the boat.
Last I would cover the raw opening with a decorative something.
Thoughts/considerations?
Many thanks for your interest.
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