[C38] Thru-hull fittings

[Jon Whitney]

Hi All,

I'm preparing for my first haul-out since buying our 1979 C38 a couple 
years ago and am seeking some advice on re-doing our thru-hulls.  All 4 
of the current thru-hulls (head intake, sewage out, galley sink out, and 
engine intake) are all configured with in-line ball valves threaded 
directly onto the thru-hull fittings (i.e., no seacocks) and mismatched 
thread sizes (NPS on thru-hull to NPT valves). All 4 are badly corroded 
(presumably due to non-marine rated valves).

 From what I can tell (measuring them in place) the thru-hulls sizes are 
as follows:
Head intake (under vberth): 1/2" NPS
Galley sink out (under galley sink): 1/2" NPS
Engine intake: 1/2" NPS
Head/sewage out: 1 1/4" NPS

Are these sizes consistent on other hulls? They don't all match what my 
blueprints say (e.g., galley sink out and sewage out are listed as 3/4" 
NPS)

I am wondering what others have done when replacing their thru-hulls. I 
would like to install proper flanged seacocks for each one, but am 
having trouble finding flanged seacocks for 1/2" NPS thru-hulls (none of 
the manufacturers I have looked at carry them, e.g., Groco, Apollo, Buck 
Algonquin). I'm curious if others have run into this issue and what 
solutions you have found. If I can't find 1/2" seacocks, then have 
others resized the thru-hulls to 3/4" so I can fit them with the proper 
hardware? Should the engine intake be 3/4" anyway?  For obvious reasons 
I would like to avoid having to have to re-drill thru hulls to up the 
size, but am looking for best options.

Any help or suggestions would be greatly appreciated. Thanks in advance 
for any advice.

Best,
Jon Whitney
"Eye Whitness"
1979, Hull 54
Honolulu
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