Seacocks

[MontyMariner]

Where do you measure on a seacock to determine its size?

I might have answered my own question!
I measured across the pipe elbows into the seacocks and got approximately 22mm and 28mm

 

[KompetentKrew]

Winds me up. I swear I looked this up, but still ended up ordering the wrong size.

To the end of my days I'll have a vendetta with SVP because they were adamant about charging me a 10% or 15% restocking fee.

 

[sigma38dave]

Yes a minefield, I take the old bits into the shop to check and even then I’ve been caught out by tapered and parallel threads!

The most painful experience was fuel line fittings involving a mix of BSP and UNF threads…grrrr.

 

[fredrussell]

I think that the general rule with pipes and fittings is that it’s the internal diameter of the pipe that is used as the measure. So a 1.5” skin fitting will be sized/designed to fit a pipe with an internal diameter of one and a half inches.

 

[Boathook]

I think that the general rule with pipes and fittings is that it’s the internal diameter of the pipe that is used as the measure. So a 1.5” skin fitting will be sized/designed to fit a pipe with an internal diameter of one and a half inches.

I prefer to use the outside diameter. The wall thickness of fittings can vary a lot nowadays. Years ago I could just look at a fitting and know the size. Not now

 

[MontyMariner]

I measured across the pipe elbows into the seacocks and got approximately 22mm and 28mm

So is that 1" and 3/4" BSP?
I might have answered my own question, but still not sure what size I need

 

[lustyd]

Winds me up. I swear I looked this up, but still ended up ordering the wrong size.

Same here. Had a thread here, discussed it, measured, still got it wrong

 

[lustyd]

So is that 1" and 3/4" BSP?
I might have answered my own question, but still not sure what size I need

Bear in mind that hose barb and thread size are not necessarily related. Truedesign certainly have a range of hose tails that step down.
Are you trying to measure the through hull thread to replace the cock or replacing everything to fit a hose size?

 

[MontyMariner]

Not decided, whatever is easiest, but I won't be replacing the hoses.

 

[LittleSister]