Seacocks for scuppers

[trevor.harris]

Hey all,

Two questions.

My inspector would like to see some seacocks places in my scuppers. I've taken off the hose, and am about to take off the seacock itself. The current one transitions to a barb, so to install the seacock I'll need to get one that's threaded all the way through. I've picked up both a bronze and plastic option. I've also found a neat plastic fitting that will simply some drainage piping as well.

I've googled this and the jury is out. Bronze or plastic. I can understand that the bronze has more strength, and these fittings are in my lazarettes, which can get bumped. But, they are twice the cost. My second question is if I can use the plastic fitting with the bronze ball valve - is that a nono?

Thanks in advance!

Trevor

[SailingHarmonie]

If the scubbers end underwater, and have hoses connected to them, then I would 100% agree that a seacock is needed. Hoses fail.

As for what fittings.. it depends. You can mix and match if you know what you are doing. You need to be sure that you have the right pieces and installed the right way for strength. SOME plastic fittings have special buttress threads that are not compatible. Others are. The fitting and the valve should all have straight (non-tapered) threads to ensure full engagement. Do NOT use regular valves with NPT threads. Use REAL purpose made seacocks.

[deblen]

https://marinehowto.com/seacock-thru-hull-primer/

[Uncle Bob]

Originally Posted by trevor.harris

Hey all,

Two questions.

My inspector would like to see some seacocks places in my scuppers. I've taken off the hose, and am about to take off the seacock itself. The current one transitions to a barb, so to install the seacock I'll need to get one that's threaded all the way through. I've picked up both a bronze and plastic option. I've also found a neat plastic fitting that will simply some drainage piping as well.

I've googled this and the jury is out. Bronze or plastic. I can understand that the bronze has more strength, and these fittings are in my lazarettes, which can get bumped. But, they are twice the cost. My second question is if I can use the plastic fitting with the bronze ball valve - is that a nono?

Thanks in advance!

Trevor

That plastic valve pictured looks like a plumbing ball valve from a big box store, not something I would want below the waterline on my boat. The metal valve looks like yellow brass, I would use bronze which is what the through hull and hose barb appear to be.

[HopCar]

The plastic seacocks we talk about are fiber reinforced plastic, not just plain old pvc.

Brands to look for are Forespar and TruDesign.
My preference in plastic seacock would be a TruDesign ball valve with a load bearing collar.

[s/v Jedi]

None of the items you show are suitable and the inspector will not accept these. You need either a fiber reinforced plastic or bronze, not PVC or brass.

Also, the backing plates look like in need of replacement too. For the Groco parts, I included a reasy-made option but you can cut one from a piece of G10 fiberglass yourself.

Here is a suitable option in plastic: https://defender.com/en_us/forespar-...room-thru-hull

In bronze:
Backing plate: https://defender.com/en_us/groco-bb-...-backing-block
Thru hull fitting long model: https://defender.com/en_us/groco-com...ll-without-nut
Flanged adapter: https://defender.com/en_us/groco-ibv...langed-adapter
Valve: https://defender.com/en_us/groco-ibv...ine-ball-valve
Pipe to hose fitting: https://defender.com/en_us/groco-bro...dapter-fitting

[ranger58sb]

Originally Posted by trevor.harris

My inspector would like to see some seacocks places in my scuppers.

I'm sorta surprised he wants seacocks on scuppers. Haven't ever seen that before, only on intake thru-hulls...

-Chris

[Statistical]

Originally Posted by ranger58sb

I'm sorta surprised he wants seacocks on scuppers. Haven't ever seen that before, only on intake thru-hulls...

-Chris

It depends on the location. If the thruhull for the scupper drain is below the water line the ocean doesn't care if it is an outgoing line or not when the hose breaks off or a load shifts and smashes the valve.

So that is the primary consideration. If the drains drain to below the water line then proper bronze or marine grade "plastic" seacocks should be used and they should be reinforced with backing board or collar depending on the design.

If the drains are to above the waterline then it isn't required. If a hose breaks off the ocean isn't going to try and invade the boat. That becomes more a personal preference. I still wouldn't use the brass pictured that is going to corrode rapidly.

[pcmm]

Originally Posted by ranger58sb

I'm sorta surprised he wants seacocks on scuppers. Haven't ever seen that before, only on intake thru-hulls...

-Chris

No...EVERY opening below the waterline OR near the waterline needs the ability to be closed, The only exception to this is typically the engine exhaust.

Its pretty much standard.

[ranger58sb]

Originally Posted by Statistical

It depends on the location. If the thruhull for the scupper drain is below the water line the ocean doesn't care if it is an outgoing line or not when the hose breaks off or a load shifts and smashes the valve.

So that is the primary consideration. If the drains drain to below the water line then proper bronze or marine grade "plastic" seacocks should be used and they should be reinforced with backing board or collar depending on the design.

If the drains are to above the waterline then it isn't required. If a hose breaks off the ocean isn't going to try and invade the boat. That becomes more a personal preference. I still wouldn't use the brass pictured that is going to corrode rapidly.

Originally Posted by pcmm

No...EVERY opening below the waterline OR near the waterline needs the ability to be closed, The only exception to this is typically the engine exhaust.

Its pretty much standard.

Thanks guys; I'd forgotten about that whole sailboat healing thing.

Haven't ever seen scupper seacocks on the boats I'm more used to.

-Chris