Learned about PVC thru hull fittings failing today!

[Island Dreamer]

I have been wondering why I get about a gallon of water in my bilge each time I go out. Today I discovered the little round hatch in the corner of the V berth close to the hull and underneath the cushion. When I Iooked in I could see that the fitting was loose and I could see daylight outside! This was the exit for my fore bilge pump. Turns out the PVC portion on the outside had sheared off! With a gentle pull, the line and the fitting detached from the inside. It was only being held on by the old 4200. A friend said they get brittle and can fail from wave action.
So now I'm debating if I should use SS or PVC? Do I let the 4200 cure a bit before snugging everything tight?

 

[Andy]

I have been wondering why I get about a gallon of water in my bilge each time I go out. Toady I discovered the little round hatch in the corner of th V berth close to the hull and underneath the cushion. When I Iooked in I could see that the fitting was loose and I could see daylight outside! This was the exit for my fore bilge pump. Turns out the PVC portion on the outside had sheared off! With a gentle pull, the line and the fitting detached from the inside. It was only being held on by the old 4200. A friend said they get brittle and can fail from wave action.
So now I'm debating if I should use SS or PVC? Do I let the 4200 cure a bit before snugging everything tight?

I'd recommend 'bronze' for thru-hull fittings.... certainly not PVC.

 

[Brent]

Use SS fitting .

What size hole?

 

[Andy]

I have been wondering why I get about a gallon of water in my bilge each time I go out. Today I discovered the little round hatch in the corner of the V berth close to the hull and underneath the cushion. When I Iooked in I could see that the fitting was loose and I could see daylight outside! This was the exit for my fore bilge pump. Turns out the PVC portion on the outside had sheared off! With a gentle pull, the line and the fitting detached from the inside. It was only being held on by the old 4200. A friend said they get brittle and can fail from wave action.
So now I'm debating if I should use SS or PVC? Do I let the 4200 cure a bit before snugging everything tight?

I agree Stainless Steel is fine for above-waterline thru-hulls. but I still prefer bronze. Just my opinion.
Our last boat (a 1986) had 18 thru-hulls; all of them bronze; eight of those are below the water-line.
All of them are in use to this day; most look 'like-new', and the boat has been in the water for 35 years (other than for the occasional hull-outs for bottom paint.

 

[pelagic2530]

Stainless for above the waterline. Gemlux is a good source.

Bronze for below the waterline. Defender, Jamestown Distributors, and Groco are good sources.

PVC never in the hull; possibly for portable live wells, tubs, or other things that will not cause water intrusion when they break.

 

[knotflying]

Try this, best of both worlds. Chrome plated bronze thru hull

 

[warthog5]

316 Series Stainless above the waterline.