Seacocks - Bolt Thru or Not

Oct 30, 2019
574
I'm installing two flanged seacocks this weekend. The holes are cut, everything dry fit good, the marine plywood backer blocks are cut and getting epoxy this week (just put the third coat on).

Question: Which method, 1 or 2, should I use? What method have most other people used? Read on...

Method 1: attach the seacock flange to the wood backer block, screwing the four screws through the wood block. In this method, the screws are captivated between the wood and the hull. However, we avoid drilling four more holes in the hull.

Method 2: attach the seacock flange to the wood backer block, screwing the four bronze screws through the wood block and the hull, and apply 4200 to the bolt heads on the outside of the hole to seal them. In this method, the seacock is attached to the hull via both the thru-hull and the four screws. However, it requires four more holes in the hull.

As always, I appreciate all of your advice and personal experiences.

Thanks,

Jack
Bella - V2620
 
Oct 30, 2019
1,459
Jack:
On my 4 thru hulls below the water line I drilled right through the hull (3 holes each), as it felt "better" to do this. My thought at the time was that as the through-bolts were below the waterline they would not show.

On my cockpit drain thru hulls with shut-offs I used the other method, as the bolts would have shown on the transom.

Both methods seem to work equally well, and were included in the Groco installation sheet.

Also, the surveyor said either way was acceptable to him, so I guess its a matter of personal choice, which probably doesn't help you at all !!

Peter
#1331 'Sin Tacha'