Thru-hull fittings

[sweet addiction]

Can anyone please tell me why these are not recommended for below waterline use? My boat is used in fresh water and is not slipped. I am re-doing all my thru-hull fittings and the Garboard drain plug. I see there are stainless drain plugs but every type of stainless thru-hull fitting I see be it plated poly, actual stainless or even plated bronze are all "not recommended for below waterline". I have a background in the swimming pool industry so I am very familiar with bonding and corrosion issues. It just does not make sense to me that a stainless drain plug is okay but a thru-hull fitting is not.

 

[H20Rat]

the outside isn't the problem, it is the inside. Lots of fragile connectors and tubing, if any one of those break, you sink. Also, it is a difference of terms. Underwater thru-hulls are called seacocks, and often have a valve on them. (yes, technically the valve is the seacock which attaches to its own thru-hull, but often sold as a unit.)

Also generally different construction. (much beefier, and bolted, not just screwed down.) Personally if I had a slipped boat with underwater thru-hulls, I"m absolutely closing the valves on those if I'm not around!

 

[sweet addiction]

The current (factory) fittings are exactly like the fittings in the link I posted. The ONLY difference is the chrome plating. Smokingcrater, This is on a non-slipped 18' fiberglass fish n ski boat. What you are talking about and the pic does not pertain to my situation. Being in the inground pool industry for 13 years now, I know about plumbing and connections and the importance of doing things right. The question is why is all of the stainless or chrome plated fittings not recommended for under the water line? It this situation the plumbing is not the issue.

 

[Grub54891]

As smoke says,and they are plastic. Not on my boat! Plastic can't be trusted to hold up to the stresses involved from hoses,and no way to shut them off if there is an issue.

 

[sweet addiction]

Nevermind

 

[Comogene]

Ok, but I was going to explain why the difference.

 

[Frank Acampora]

Over the years I have learned one good thing: It is easier to follow a manufacturers recommendations than to question them and repent later. If it says not for below waterline use--it simply is not for below water line use. If an engine manual says to use a certain spark plug, USE THAT PLUG. Don't try to make do with a different heat range. Some things in life are really simple to screw up--it only takes a little knowledge. Like the maxim says: A little knowledge is a dangerous thing.