E27 Seacocks

[Tom Prince]

I am in the process of replacing the antiquated ball valves with new seacoks and have an E27 specific question. The existing installation of the ball valves is flush mounted, rather than mushroom. When I removed the old plumbing and plywood pads there was a built up lip of fiberglass under the ply. This served to reduce the diameter of the hole for the thru hull from about 2 inches down to either 3/4 or 1 1/4 inches. I am now faced with oversized holes for the actual thru hull threaded piece. The flange part will be fine as the existing cut on the outside is a perfect fit for the flush mount end. Am I making this clear? Anyway I do not want to hollow out the back of the ply as Ericson did to allow a fiberglass dam.. Any experience with this? Probably the same arrangements on the E29.... By the way not one blister, and thats a Hawaii boat!!! Ericson quality hand lay up in 1973.

Thanks,
Tom

 

[Emerald]

Hi,

I had an E-27 with flush mounted thru-hulls and did the same drill you are going through. I am a little confused by what you are describing. Just to be sure we are on the same page, you have a set of new flush mounting thru-hulls to install? If this is the case, they should fit into the recess flush on the exterior of the hull, and there should not be any void between the thru-hull and the hull. In general, on the interior side of the hull, you should be replacing the backing pads with round, epoxy coated, marine ply. I do not recall having any issues with an uneven surface on the interior side of my E-27, and bedded the pads down in my favorite goo as part of assembly.


Now, the water intake for the engine and the head is originally 1/2 inch and to go to flanged seacocks you need to increase the stem size to 3/4 inch. I was able to find flush mounting thru-hulls that fit the recess and had the 3/4 stem. I then just used a hole saw to enlarge the center hole for the larger stem. Note, you can use a wood plug stuck in the old hole to hold your pilot bit and get the cut started and make it much easier to keep everything on center.


Here's a link to a page I put together on doing thru-hulls. Most of it is from my E-27, and includes fixing a torn up seat.


http://home.comcast.net/~ericson-yachts/thull/thull.html


Hope this helps.


-David
Independence 31
Emerald

 

[Tom Prince]

Seacocks

David, The hull thickness where the seacocks pass thru the boat is about 3/8 inch. Evidently when they drilled the holes at the factory the drill they used to create the taper for the flush thru hull was the diameter of the inside of the flare for the flanges(about 2 inches). They then built up,on the inside of the hole a dam of fiberglass to reduce the size of the hole down to the diameter of the threaded piece. They must have then set the ply on wet resin and then bored for the pipe. Hard to describe. I was just trying to avoid having to play with resin and glass. I am just going to grind it down flush to the surrounding area inside the hull and build up layers to do the same thing, but 6 inches in diameter so my ply block is sitting on a flat area....Thanks for the information.
Aloha, Tom

 

[Jarod]

Just did this job

Hi
I just did this job last week on my boat...I had the original ball valves on mine as well with the plywood backing plate on the thickened lip on the inside...I ended up building up the inside lip with west epoxy thickened with colloidal sillica. I then slathered a generous amount of epoxy on the plywood disk and set it in place...once it had cured i went outside and drilled the hole the same size as the one in the hull....granted there was a bit of play around the threads on the thru hull and the inner circumference of the plywood backer...but in my estimation a gap is a gap and it wasnt too too much.. I applied a generous amount of 3m 5200 to the inner diameter of the hole and pushed the through hull in and tightened it up...if that gap scares you and you want to be extra sure....epoxy around the gap where the flush mount lip meets the hull....that sucker wont go anywhere nor will it leak...that west systems stuff is damn tuff ...

jarod