Sea Cocks

[bretto55]

Hi Fellow yachties,
I'm going on the hardstand soon. I need to change my sea cocks. I have brass fittings ATM. Should I stay with brass or is PVC better or worse?

[StuM]

Not brass or PVC. Bronze or Marelon type glass reinforced plastic is the only way to go. Personally, I'd go with bronze.

[crazyoldboatguy]

Can you even buy brass seafocks?

[Boatyarddog]

Originally Posted by bretto55

Hi Fellow yachties,
I'm going on the hardstand soon. I need to change my sea cocks. I have brass fittings ATM. Should I stay with brass or is PVC better or worse?

Are you installing seacocks or ThruHull fittings and ball valves?


Sent from my iPad SV Cloud Duster

[Idle]

I have replaced all the seacocks and thruhulls with marelon. It is almost only 2 years by now and no problem so far. They were brass, 12 years old , 7 in total . Looking at them non was faulty. When took out, 2 thruhulls were in the condition of hard chocolate, ready to fall into pieces. Marelon is said to be strong, definitely no corrosion and very light compared to brass or bronz. Best brass is not dependable after 5 years. Have a look at the links below.
Would not advice PVC definitely.
Idle

http://www.paulstevenssurveys.com/upload/Seacocks.pdf
Installing a Seacock by Don Casey - BoatTECH - BoatUS

[Twill]

Since this is a Seacock thread I need some advice. Can you or should you apply heat to a frozen bronze seacock ? PB blaster is not doing the job. Any other advice would be appreciated. The boat is in the water and dry...Twill

[Boatyarddog]

Originally Posted by Twill

Since this is a Seacock thread I need some advice. Can you or should you apply heat to a frozen bronze seacock ? PB blaster is not doing the job. Any other advice would be appreciated. The boat is in the water and dry...Twill

If it's a traditional type seacock, you can probably disassemble it, as in my boat.
This type can be maintained, by removing a lock nut and adjusting nut, and tapping it out.
If it's a ball valve, and threaded ThruHull type, no heat on the ball valve, they have a sealing area internally, that could be damaged.
Try penetrant, or replace it.
If you replace it, be sure not to let the threaded ThruHull turn as well, it breaks the seal and will leak.
Hold with a pipe wrench the neck of the threaded part or if the space is tight, try a chain wrench.
Threads will be sacrificed, but usually this will not affect the threads that screw to the ball valve.


Sent from my iPad SV Cloud Duster

[Terra Nova]

Use a thru-hull wrench. Penetrant probably won't help. If very seriously corroded, use a Sawzall. Buy Groco or equal bronze seacocks. Check/replace backing plates.

[Aussiesuede]

Originally Posted by Boatyarddog

If it's a ball valve, and threaded ThruHull type, no heat on the ball valve, they have a sealing area internally, that could be damaged.


If you replace it, be sure not to let the threaded ThruHull turn as well, it breaks the seal and will leak.

This is precisely why I prefer the practice of using an elbow thru-hull as opposed to having a Seacock/Thru-hull as a mono-unit. Less Chance of breaking loose the thru-hull when messing with a fussy seacock.

[Terra Nova]

Originally Posted by Aussiesuede

This is precisely why I prefer the practice of using an elbow thru-hull as opposed to having a Seacock/Thru-hull as a mono-unit. Less Chance of breaking loose the thru-hull when messing with a fussy seacock.

This is not a safe choice where you need a sea cock.

[bretto55]

Thank-You all.

[Reverie27]

I am about to replace three of the five thruhulls on my Mirage 27 with Marelon Seacocks. I read Don Casey's guide to proper installation of Seacocks, however I cannot bring myself to drill nine additional holes in the hull so that I can through bolt the Seacocks as Mr. Casey recommends. I do plan to install 3/4" plywood mounting pads between the Seacocks and the hull. I am wondering if simply using screws to fasten the Seacocks to the mounting pads, which will be epoxied to the inner hull, sufficient, along with the thruhulls threaded on from the exterior. As a side note, I am replacing original thruhulls that had gate valves. The two thruhulls not scheduled for replacement this haul out are the cockpit drain thruhulls and valves, which are the only valves that remain open at all times.


Sent from my iPad using Cruisers Sailing Forum

[Boatyarddog]

Looks like Forespar does it without drilling the holes for the mounting flange.
I'm assuming that it's a way of keeping the location of the valve true to the ThruHull fitting and to reduce any chance of twisting the flange.
You've probably read this by now.
Attachment 98962
Sorry I could not crop the photo.
Seems they Forespar, epoxies a 3/4" backing plate, marine plywood and sealed, to the hull and screws the flange to it.
If the Manufacturer recommends that install practice it going to be ok.
My Opinion.


Sent from my iPad SV Cloud Duster

[rwidman]

I hope nobody actually has brass seacocks or brass anything that comes into contact with seawater. Bronze is the proper metal to use. Marelon is the proper non-metallic material to use.

[Reverie27]

Thanks for the tip, amazingly enough, given the amount of time I spend trolling the Internet for boat info, that I completely missed the Forespar manual. I am relieved to hear that I do not have to drill additional holes in my hull. Now I just have to find source for quarter or half sheets of marine plywood, as the specialty lumber supplier only sells full sheets, way more than I need for three Seacocks pads. A line on. A source in Canada, as the exchange rate is not favourable right now, would be much appreciated.


Sent from my iPad using Cruisers Sailing Forum