Skin fitting and valve sizes conundrum for heads outlet

[Keith-i]

I'm looking at replacing my aging dzr valves and skin fittings with Trudesign components to give peace of mind on future corrosion. Whilst the butyl sanitation hose is 38mm it seems like there is a bit of choice regarding valve size as the suitable 38mm hose tail can come with either 1.5" or 1.25" threads. Interestingly, both the 1.5" and 1.25" Trudesign valves both have the same internal bore diameter of 32mm.

So, the question is, is there any convention regarding choice. Do I stick with a 1.25" valve but use a 1.5" (38mm) hose tail or is there any benefit of matching the 1.5" hose tail to a 1.5" valve?

 

[pvb]

If they have the same bore diameter, it really doesn't matter which you choose.

 

[superheat6k]

I would go with what the original hole will accomodate.

I would also suggest you consider Forespar Marelon as well as Tru Design. I've fitted these throughout and they seem excellent and no more bonding circuits everywhere.

 

[pvb]

...and no more bonding circuits everywhere.

Seacocks don't need bonding.

 

[RJJ]

I would go with what the original hole will accomodate.

I would also suggest you consider Forespar Marelon as well as Tru Design. I've fitted these throughout and they seem excellent and no more bonding circuits everywhere.

Likewise. I would start from the skin fitting and work inward. The skin fitting gives you the ball valve size. Or you can start from the hose and work outward; which could leave you needing to change the size of the hole in your boat. I'd prefer the former; when I did mine earlier this year I found one of my 12 fittings called for a 1.25in skin fitting+ball valve onto a 1.5in hose tail and hose. I found an ASAP hose tail that made the adjustment for me.

The S dimension indicates the skin fitting for 32mm or 38mm does indeed have a different external diameter; therefore the ball valve internal diameter is different; and the output hose tail thread diameter is different.

Tru Design Seacock Kit 1 1/4

Are you perhaps muddling the thread length (which is the same) with the thread diameter?

Tru Design Long Thread Tail 90285, 1¼

 

[vyv_cox]

I'm looking at replacing my aging dzr valves and skin fittings with Trudesign components to give peace of mind on future corrosion. Whilst the butyl sanitation hose is 38mm it seems like there is a bit of choice regarding valve size as the suitable 38mm hose tail can come with either 1.5" or 1.25" threads. Interestingly, both the 1.5" and 1.25" Trudesign valves both have the same internal bore diameter of 32mm.

So, the question is, is there any convention regarding choice. Do I stick with a 1.25" valve but use a 1.5" (38mm) hose tail or is there any benefit of matching the 1.5" hose tail to a 1.5" valve?

You may well have ageing brass valves and skin fittings but not DZR ones I suggest. DZR valves have been around for a while but not in general use for yachts. DZR skin fittings were introduced quite recently, less than five years I think, similarly hose tails. DZR components are always marked as such, either with the CR mark cast into the body or engraved, as in the photos, or more recently I have seen skin fittings and hose tails marked as DZR.