Here is a post I made to Yahoo groups just before CP was created:
After seeing Megabyte's report on his bilge upgrade last year, and
seeing how easily his thru-hulls snapped off, I put this project on
my TO-Do list for the spring. My boat is a 1999 21' DVCC that I
purchased a year ago.
I went out back and crawled under the tarp this afternoon to take a
better look and was surprised by what I found. Maybe I've been
reading THT for too long, but I was surprised to see that the thru-
hull was the 90* type and that the hose ran straight down through
to the bilge pump and was unsupported along its length.
In my boat, access to the thru-hull is through the corner-
seat/storage box in the stern, and as you can see in the picture,
there isn't enough room to get a loop in above the thru-hull to
prevent water from coming in. On top of that, the solid, smooth-
bore bilge hose that I purchased isn't very flexible.
See these two pics:
View of stern box showing thru-hull:
View of bilge hose coming down from above and running straight to
bilge pump unsupported:
From my research on THT, I can see that a check valve or joker valve
isn't a recommended solution for a bilge pump. So, is there
anything else I can do to limit water coming in? I ran the boat
last season in all kinds of conditions and never had any trouble
with water coming in, so I'm not that worried about it.
Also, the requirement for a 90* thru-hull limits my options pretty
quickly if I want to stay with the same size mounting hole. I
couldn't find any 90* chromed over bronze, stainless, or Marelon
fittings for 1 1/8" hose and 1 3/8" mounting hole. Looks like I am
limited to the cheaper plastic types, with TH Marine being the best
bet. I looked at several other brands on-line, and couldn't find
any others that would work (SeaChoice & Cabelas didn't list the
mounting hole size; Attwood & Rule use different hole sizes).
Just wondering if anyone else has any other options or ideas? I'd
love to find a source for a higher-quality plastic version.
I am planning on installing a second bilge-pump, so maybe I
shouldn't worry about it and just make sure that I check the
condition of the plastic thru-hulls regularly?
-- Tom
After seeing Megabyte's report on his bilge upgrade last year, and
seeing how easily his thru-hulls snapped off, I put this project on
my TO-Do list for the spring. My boat is a 1999 21' DVCC that I
purchased a year ago.
I went out back and crawled under the tarp this afternoon to take a
better look and was surprised by what I found. Maybe I've been
reading THT for too long, but I was surprised to see that the thru-
hull was the 90* type and that the hose ran straight down through
to the bilge pump and was unsupported along its length.
In my boat, access to the thru-hull is through the corner-
seat/storage box in the stern, and as you can see in the picture,
there isn't enough room to get a loop in above the thru-hull to
prevent water from coming in. On top of that, the solid, smooth-
bore bilge hose that I purchased isn't very flexible.
See these two pics:
View of stern box showing thru-hull:

View of bilge hose coming down from above and running straight to
bilge pump unsupported:

From my research on THT, I can see that a check valve or joker valve
isn't a recommended solution for a bilge pump. So, is there
anything else I can do to limit water coming in? I ran the boat
last season in all kinds of conditions and never had any trouble
with water coming in, so I'm not that worried about it.
Also, the requirement for a 90* thru-hull limits my options pretty
quickly if I want to stay with the same size mounting hole. I
couldn't find any 90* chromed over bronze, stainless, or Marelon
fittings for 1 1/8" hose and 1 3/8" mounting hole. Looks like I am
limited to the cheaper plastic types, with TH Marine being the best
bet. I looked at several other brands on-line, and couldn't find
any others that would work (SeaChoice & Cabelas didn't list the
mounting hole size; Attwood & Rule use different hole sizes).
Just wondering if anyone else has any other options or ideas? I'd
love to find a source for a higher-quality plastic version.
I am planning on installing a second bilge-pump, so maybe I
shouldn't worry about it and just make sure that I check the
condition of the plastic thru-hulls regularly?
-- Tom