TruDesign seacocks and hull thickness

[Clyde Coastin']

Hello YBW Hivemind,

I have a question regarding TruDesign seacocks and skin fittings.

I am replacing the old DZR units on my boat with a number of 3/4 inch and 1 inch TruDesign units. All of these will be fitted with load collars.

The issue is my hull is 10mm thick in the areas, all under the waterline, where I want to fit valves. I've seen varying TruDesign information saying that the minimum hull thickness is 20mm. I emailed TruDesign as the online document revisions are all over the place, and got a bunch of PDF's back that only mention MAXIMUM thickness, I've asked for clarity on this but no response yet.

Should I buy 10mm GRP backing pads as a precaution? Will these need expoxied in? (temperatures will be a challenge in March in Scotland) or can I use 4200 / 5200 to bond the backing pads on?

I'm tempted to phone my surveyor!

Any and all thoughts on the matter would be amazing!

 

[RunAgroundHard]

West System 105 Resin with 205 Fast Hardener is for cold temperatures, allowing curing down to 40°F (5°C).

If the minimum is 20 mm then use some GRP sheet to make up the difference and bond in place.

 

[potentillaCO32]

Hello YBW Hivemind,

I have a question regarding TruDesign seacocks and skin fittings.

I am replacing the old DZR units on my boat

Should I buy 10mm GRP backing pads as a precaution? Will these need expoxied in? (temperatures will be a challenge in March in Scotland) or can I use 4200 / 5200 to bond the backing pads on?

Yes. But you can make the backing plates with grp very easily. Thickened epoxy the best way to bond in and take account of hull curvature.
In cold weather i use an 80w heat tube to warm the area with the epoxy.

 

[rollover]

Yes. But you can make the backing plates with grp very easily. Thickened epoxy the best way to bond in and take account of hull curvature.
In cold weather i use an 80w heat tube to warm the area with the epoxy.

Hello YBW Hivemind,

I have a question regarding TruDesign seacocks and skin fittings.

I am replacing the old DZR units on my boat with a number of 3/4 inch and 1 inch TruDesign units. All of these will be fitted with load collars.

The issue is my hull is 10mm thick in the areas, all under the waterline, where I want to fit valves. I've seen varying TruDesign information saying that the minimum hull thickness is 20mm. I emailed TruDesign as the online document revisions are all over the place, and got a bunch of PDF's back that only mention MAXIMUM thickness, I've asked for clarity on this but no response yet.

Should I buy 10mm GRP backing pads as a precaution? Will these need expoxied in? (temperatures will be a challenge in March in Scotland) or can I use 4200 / 5200 to bond the backing pads on?

I'm tempted to phone my surveyor!

Any and all thoughts on the matter would be amazing!

I’ve just done all mine on a Oceanis 40, I had various thickness of hull, with the engine coolant intake hole being only about 8mm. The through hulls are threaded the full way so no real issues.
I bought 6 support collars but only used one as unless the inside of the hull is perfectly flat, the collar won’t sit flat so doesn’t really help, and if you tighten the stop cock down onto the collar it puts a side load on the through hull. The one I left on was under the sink where it could get hit. The other issue with the collar I found was once fitted you cannot see the locking nut, or get to it if you wanted to check tightness.

 

[searocket]

My understanding is the reference to minimum hull thickness relates to thread depth on the long thru-hull fittings. The standard length (dome headed) fittings have a full depth thread and should be fine on a 10mm hull thickness.
I have replaced several of the original brass fittings with Trudesign incl collars on our 34' sailboat, they all had plywood backing pieces and I reused these - they give a flat surface. Our backing pads are fixed with sealant/adhesive.
The exposed thread of the thru-hull needs measuring and trimming carefully for the collar - details on the data sheet.