After watching all of my above water thru-hulls deteriorate over the years, I finally decided to replace them with something that would take care of itself. Some of the original fittings were vinyl which were becoming chalky while others were chromed brass. All told, there were five thru-hulls which needed replacement, the worst being the two chromed brass holding tank vents which had been badly corroded by the H2S as it wafted in and out.

The SS fittings I used were by Groco and were the ideal solution where there is no room to install a hose, let alone the necessary internal raised loop. The outside thread on these fittings is NPS while they are internally threaded with a one pipe size smaller NPT thread. This allows a 90 deg. street ell to be installed in the thru-hull fitting which make for a compact installation. A little more expensive but worth their weight in gold.

Although the shape of these fittings look as if they are just waiting to be flooded by a wave, they all have an internal loop which, in all cases, goes up to the underside of the deck.