Cape Dory 27 Mast Compression Plate

[sailor_grant]

Hi All -

I have noticed that my thru-hull wiring hole was not properly created and has likely allowed moisture to ingress around the mast. I am worried that this will cause corrosion of the steel integral mast compression plate or the wood core.

Does anyone know if there is a wood core where the compression plate is or just a steel plate? Does anyone have experience with this?

Thanks!

[fmueller]

Grant,

On my 27 (hull 204) I have a 1” hole that allows the wires from the mast to pass thru the cabin trunk roof. Right between the mast and dorad box - only about an inch from the mast. Tight. I’ll try to post a pix here eventually. A Blue Sea Cable Clam caps the drilling and is sealed by a gasket. I have also formed an additional clear silicon “cap” around the clam and cable bundle the wrapped the bundle in rigging tape. . The hole reveals a substantial wood core sandwich structure of almost an inch in this spot - plywood I think. On my boat the exposed core is sealed finger paint style with silicon caulkthe.

Whether the wood core continues across the raised section of the cabin trunk where the mast is stepped I can’t say. Sorry I can’t provide a direct answer to your question. But any water that is getting into that layer will rot wood and rust steel. I cut a substantially larger utility opening in the headliner just inboard of the dorad so I could fix a barrier strip and have an organized way of uncoupling the wires when the mast comes down every 3-4 years. It allows for a good look around at the area under the mast. I made a nice cover for the opening. It’s about 9”x9”. I’d suggest you do the same and that would allow you to drill a few pilot holes from the underside and survey the state of your wood core and maybe even the metal piece which I suspect is just a mild steel plate kind of like the OEM chain plates. From the underside it’s easy to see the fore to aft bulge on the layup where this plate is encased. Any holes you drill could be filled if all is well. I’m talking about 1/4 or 3/8” holes. They would not affect strength and might give you peace of mind. Rotted core is easy to spot.

At one point I had intermittent leaking coming down on the headliner below the drilling and could not figure it out until I replaced all the wiring in my mast and realized the three way wire to my mast head light and steaming light was wicking water all the way down into the boat. Water finds a way unbelievably sometimes. The tops of Spartan masts are open and rain runs down the insides of our masts and needs a pilot hole exit at the step and also wire casings need to be sealed against seepage usually with silicone.

[sailor_grant]

Can you post picture of your solution, would be great to see as I am planning on redoing it. I over drilled and lined with epoxy, luckily no rot. But want to make a cleaner solution

[fmueller]

This is an old thread ... here are a few pix from inside ... . In the first shot you can just make out the 1" through deck hole which I coated with white silicone. There is a deck side cable clam at the top of that drilling. I'll have to take a shot and post. The gland was on the boat when I bought her in 2013. I just added the caulk and sealed the wire bundle with rigging tape and silicone above deck. Most importantly, with the liner cutout I can now inspect for leakage easily ... there has been none.

Here is a Google cable clam search:

https://www.google.com/search?sca_esv=7 ... sid=mosaic

3.jpg

2.jpg

1.jpg

[keneasley]

Hello Fred,

I like the 9x9 cover that you made. What material did you use?

I plan to do similar - enlarge an existing opening for the mast wires and take a few core samples.