Flanged seacocks vs Inline Valve with Thruhull and backing block

[Jammer]

I am in the process of replacing two ball valves with seacocks. One of them had failed and was leaking.

<<< it's all just speculation >>>

Decades of actual field experience is not speculation. Proper seacocks have a good reputation that goes back years and years. Inline valves do not.

<<< 500 pounds >>>

Any resilient object of reasonable weight (20+ pounds) that is dropped or thrown can exert this much force. It is not a hypothetical scenario.

<<< Marelon >>>

It's your boat, do what you want.

Properly installed and with minimal maintenance, bronze seacocks should last the life of the hull, and often do.

My experience with plastic valves of various kinds is that they deteriorate over time due to cumulative exposure to the atmosphere, the sun, fluids, temperature changes, etc. As noted upthread dimensional stability is a problem. Cold flow is also a problem. Loss of plasticizers over time is a problem, as noted in the case of schedule 80 PVC upthread. Migration of components within the material is a problem. Maybe the Marelon ones solve all that. I am skeptical and am unconvinced that they solve any problem that I actually have with bronze.

[bcboomer]

Originally Posted by Jammer

I am in the process of replacing two ball valves with seacocks. One of them had failed and was leaking.

<<< it's all just speculation >>>

Decades of actual field experience is not speculation. Proper seacocks have a good reputation that goes back years and years. Inline valves do not.

<<< 500 pounds >>>

Any resilient object of reasonable weight (20+ pounds) that is dropped or thrown can exert this much force. It is not a hypothetical scenario.

<<< Marelon >>>

It's your boat, do what you want.

Properly installed and with minimal maintenance, bronze seacocks should last the life of the hull, and often do.

My experience with plastic valves of various kinds is that they deteriorate over time due to cumulative exposure to the atmosphere, the sun, fluids, temperature changes, etc. As noted upthread dimensional stability is a problem. Cold flow is also a problem. Loss of plasticizers over time is a problem, as noted in the case of schedule 80 PVC upthread. Migration of components within the material is a problem. Maybe the Marelon ones solve all that. I am skeptical and am unconvinced that they solve any problem that I actually have with bronze.

Trudesign are NOT Marelon. They won't have "migration of components" any more than your hull does.

They will NOT "cold flow" any more than your hull does.

They meet the same ABYC impact standard as bronze.

Your comparison with plastic valves is just plain silly.

[boatpoker]

Originally Posted by Tessellate

This really seems like a concern about electrolysis, which is legitimate but is an argument for using Marelon, because both inline bronze and flanged bronze are susceptible to electrolysis.

Please explain how hair removal (electrolysis) or hydrogen fuel cell (electrolysis) has anything to do with this.

[HopCar]

Originally Posted by Mistress Sirena

after having encountered a few frozen ball valve"seacocks "I will choose the cone style bronze sea cocks when I can find them.

Having encountered a lot of frozen tapered cone seacocks, that require a hammer and other tools to free, I will always choose a ball valve type seacock.

While ball valves do freeze, I’ve never found one I couldn’t free with just a little extra leverage. It’s also pretty easy to prevent a ball valve from freezing. Just open and close it a couple of times a year.

On a tapered cone you have a huge area of bronze to bronze contact that can corrode and cause the valve to freeze. A ball valve has a tiny area of chrome or stainless in contact with Teflon like material. It just doesn’t have enough area to freeze as tightly as a tapered cone.

This doesn’t seem to be true for Marlon ball valve seacocks. I have seen the older design freeze tight enough that the stem breaks if you apply enough force.

Oddly the 2-1/2” Apollo ball valve seacock will break a stem once in a while. Never seen that happen with the smaller ones.

[mitiempo]

Originally Posted by bcboomer

Trudesign are NOT Marelon.

Same material without the trademarked name. Glass fiber reinforced nylon.