best thru hull for water line application

[Rodd]

I need to replace some old plastic thru hulls that are located in my boot stripe, about an inch above the water. These serve as drains for deck scuppers and are 1 1/2 inch. I know I need either Marelon or brass thru hulls. Which is better for this? and if I use Marelon I need a 90 degree bend to attach the hose from the deck drain above. Should I get a molded one piece thru hull with the 90 elbow and barbed end, or should I screw on a separate 90 degree elbow to a standard Marelon threaded thru hull?

My concern has always been that while storing in the water for the winter, if the boat gets weighed down with snow and this thru hull sinks below the water line, I want a strong thru hull so I don't sink!!

Thanks!

Rodd

 

[Barnacle Bill]

Marelon is extremely strong, so the material is not a problem. If you keep your boat in the water over the winter in a bubbled slip, then you also have to be concerned about a thru-hull or seacock freezing as well. I have seen boats sink because the thru hull was not properly winterized and the fitting froze and expanded and cracked letting water into an unattended vessel. One thing nice about Marelon is it won't corrode from galvanic corrosion where a bronze fitting could.

 

[Maine Sail]

I need to replace some old plastic thru hulls that are located in my boot stripe, about an inch above the water. These serve as drains for deck scuppers and are 1 1/2 inch. I know I need either Marelon or brass thru hulls. Which is better for this? and if I use Marelon I need a 90 degree bend to attach the hose from the deck drain above. Should I get a molded one piece thru hull with the 90 elbow and barbed end, or should I screw on a separate 90 degree elbow to a standard Marelon threaded thru hull?

My concern has always been that while storing in the water for the winter, if the boat gets weighed down with snow and this thru hull sinks below the water line, I want a strong thru hull so I don't sink!!

Thanks!

Rodd

Rodd,

The Marelon OEM/93 series come in a 90 degree seacock version. The only problem with them is they are not "full flow" valves. For example a 3/4" 93 series is really a 1/2" ID... The other potential issue with above waterline plastics is UV, which is not an issue with bronze.

 

[Ralph Johnstone]

Here's Something ..........................

.................... which may fit your needs.

These are SS thru-hull fittings which have an internal NPT thread. Ideal if you need a quick 90 deg. turn using a brass street ell. Watch your ID's carefully to ensure you have sufficient flow area. If necessary to increase the size, it's a simple matter to use a hole saw to increase the size of hole in your hull.

All my original above water thru-hull fittings were chromed brass and they were one holy mess after about five years. I've since replaced all of the brass above water fittings with these SS Groco ones from Defender. Vent lines have a large, high internal loop to prevent sea water ingress.