Are plastic thru hull fittings OK under water?

[edrow]

I need some thru hull fittings. Many plastic ones I've seen say above water line use only. I'm in freshwater only and I launch/load every time out. I cant see why they would not be OK under the waterline. Any suggestions?

 

[1957Crestliner12]

People do install plastic below the waterline...even many high-end bass boat manufacturers use to install them for live well pick-ups and drains...not sure if they still do...

There are a lot of stories of below the waterline failures with plastic thru-hulls. Plastic is not as forgiving during installation and can crack unbeknownst to the installer, deteriorates over time due to sun and weather, can crack if holding water during freezing temps, can easily crack if a loose object hits it in the bilge during rough boating conditions or trailering, etc...

Use stainless steel...yeah it's more expensive, but it's not significantly more money for the piece of mind...and a lot cheaper than salvaging a boat.

If you do install plastic below the waterline...which I don't advise...get a set of tapered wooden emergency plugs to keep within reach in case of a failure. These have saved many boats.

Rod
Oriental, NC

 

[RivrLivn]

Just be sure to get a thru-hull fitting that is approved for below the water line.
I would only use the Marelon products by Forespar.

 

[dkonrai]

did you know that most wake board boats have plastic thru hulls? mastercraft, moomba, ski natique... yes nig bad ski boats that use crappy fittings below the water line. surprised most done sink.
i would only use stainless below the water line. plastic is ok if its for a bilge but thats about it.
jmho
dino

 

[edrow]

Ok thank you guys for the replies. I've seen many plastic used on some builds, so I was curious about what I was finding. Thanks again

 

[rscottp]

The factory live well drain on my 96 Lund is plastic and has not leaked.

 

[rscottp]

1957Crestliner12 » 30 Jan 2014, 11:08[/url]"]People do install plastic below the waterline...even many high-end bass boat manufacturers use to install them for live well pick-ups and drains...not sure if they still do...

There are a lot of stories of below the waterline failures with plastic thru-hulls. Plastic is not as forgiving during installation and can crack unbeknownst to the installer, deteriorates over time due to sun and weather, can crack if holding water during freezing temps, can easily crack if a loose object hits it in the bilge during rough boating conditions or trailering, etc...

Use stainless steel...yeah it's more expensive, but it's not significantly more money for the piece of mind...and a lot cheaper than salvaging a boat.

If you do install plastic below the waterline...which I don't advise...get a set of tapered wooden emergency plugs to keep within reach in case of a failure. These have saved many boats.

Rod
Oriental, NC

Think I may switch out mine to stainless steel.

 

[edrow]

Man, even some of the SS fittings specify above water use only. Many don't specify either way. I did find some stories of people having plastic fittings break & had to plug with the wooden plugs. Great advice crestliner, thanks.