PVC vs Brass ball valves

[Taipe]

A lot of lay folks use the word brass when they should be stating a marine alloy bronze.
Anyhow, if you're concerned about corrosion of the ss ball in a marine bronze valve, you can look at the Groco valve, (the type that has a base to mount onto a hull plate) that is serviceable for replacement of the ball. I spent the extra bucks for several of them and by placing an expandable plug in the exterior thru-hull fitting, you can comfortably service them with a new ss ball with the boat in the water. Also, having this type of valve that has a base to attach indirectly to the hull, it is more secure than depending upon just the threaded neck of the thru-hull fitting. More expensive? - yes, but piece of mind when yanking on the valve arm when it requires a cheater pipe. I think it is worth the difference when in nasty conditions.

[ramblinrod]

Originally Posted by Cheechako

Good comments. One thing though, I've often wondered if a Chrome ball is actually better. What is in SS that makes it good? A small bit of Chromium. How does SS react in a closed oxygen depleted environment (like while sitting closed/unused)? It pits and corrodes.
OK, carry on.

Chrome over brass can become pitted or peeled quite early. Chrome over bronze is better, but can still peel.


If it doesn't say Apollo or Groco on it, and clearly indicate it is bronze, I don't use it.

I have replaced so many cheap plastic sea water strainers that have nearly sunk boats it is ridiculous, especially on A/C systems where the seller/installer is trying to minimize cost to make max profit.

To repeat, if a failure can sink the boat, SPEND THE MONEY to install the correct product.

[boom23]

I am not an expert but this is what Amel is doing and I trust their experience. The intake in the picture is the main/only raw water intake on the Amel 50 and it is oversized. I have not seen how the hull drains are constructed, on the inside of the hull, but I assume they are similar.

From the outside of the hull, you only see a hole.

[seatotaler]

Originally Posted by SteveSails

Do you need 1-1/4" valves on the FW side? For just a FW flush you don't need to run anywhere near full throttle so maybe 1" would be adequate. Prices of bronze valves and fittings drop dramatically from 1-1/4 to 1".

The reason I'm going with 1 1/4" dia. is that that's the size of the hose from the sea strainer to the raw water pump now. So since the fresh water coming from the tank I had built is gravity fed, I don't want to adjust the flow of water going through the impeller. Perhaps one inch hose and valves might be enough to keep up to the impeller, but who knows ??

[pilott]

I may be showing my ignorance, but why not a stainless steel valve?

[seatotaler]

I think I need to clarify something here. The first valve that is just below the water line is full of fresh water only and is gravity fed by the custom tank that holds about 15 gallons. If for some reason it should burst, it just means I'd have 15 gallons of fresh water in my bilge at the most, which would be dealt with by the bilge pump. Added to that, the flushing procedure takes place after I return from an outing. Once I've flushed out the salt water, that fresh water tank will be close to empty, until the next time I return and refill the tank from the dock water outlet at which time I'd flush out again, leaving the tank almost empty again. It's my understanding it should take about 12 gallons to flush out both engines, but that's a different topic. The second valve which will have raw water in it while under way, will be above the water line.

[sailorchic34]

Originally Posted by Cheechako

Good comments. One thing though, I've often wondered if a Chrome ball is actually better. What is in SS that makes it good? A small bit of Chromium. How does SS react in a closed oxygen depleted environment (like while sitting closed/unused)? It pits and corrodes.
OK, carry on.

Generally in a salt water environment, the chrome will peel off a brass ball in a few short years, or less. Plus the brass ball will dezinc. What really happens is the chrome goes partly away, the ball dezinc's enough for the stem to break the slot in the top of the ball. Most all ball valves fail at the ball / stem joint, which makes the ball inoperable, long before it will leak.

Pitting of SS is generally a slower issue. Does it happen, yes, but at a much slower pace. I've seen many a chromed ball look far worst.

On the question on PVC. Engine heat will age PVC. PVC is generally of low impact resistance. There have been cases where a heavy item falling and cracking a pvc ball valve. Generally the plastic valves with a lever handle are better. Avoid ball valves with a butterfly handle (Cheap ones in the big box stores for example). PVC has no place below the water line.

To the OP, PVC should last 4 years, but it would be far safer to use bronze, marlon (a type of nylon) or PE ball valves. Of course Marlon costs as much as a bronze ball valve so no savings there.

[HopCar]

Just for your information.
Groco BV series seacocks use a stainless ball.
Groco FBV series seacocks use chrome plated brass balls.
Groco ball Valves use chrome plated brass balls.
The Apollo valves (78 series?) sold for marine use have stainless balls.
Any of the above valves should outlast the boat.

[Fore and Aft]

I think the issue is what grade PVC ball valve are we talking about? If it is a marine grade fitting like the one shown in the Amel 50 then all’s good. But if you are talking an EL Cheapo standard house plumbing fitting then you have issues.
I surveyed a yacht last week that had two cheap plastic ball valve fittings. Both handles snapped of in my hands when I tried to close them. The second ball valve I was extra careful touching and it still broke! Both ball valves did not look that old. The owner was a bit pissed with me, but they broke so easy.
I am not a fan of plastic ball valves at all in the engine room. I like a metal ball valve, not sure if it helps but If there was an engine room fire I think the raw water hose would melt first. Once the fire is out I would like to be able to close the ball valve to stop any seawater coming in. I am not confident that a plastic ball would survive an engine room fire? Just my thoughts.
Cheers

[Jetx]

This... around minute 4:15... is interesting. Less expensive than bronze (still much pricier than PVC), and approved for below the water line. Note that the valve threads are either NPS or BPS, depending on the model, so you do have to buy the Trudesign threaded hose adapters also.

https://youtu.be/HAbvFl-m-Ac

[seatotaler]

Originally Posted by Fore and Aft

I think the issue is what grade PVC ball valve are we talking about? If it is a marine grade fitting like the one shown in the Amel 50 then all’s good. But if you are talking an EL Cheapo standard house plumbing fitting then you have issues.
I surveyed a yacht last week that had two cheap plastic ball valve fittings. Both handles snapped of in my hands when I tried to close them. The second ball valve I was extra careful touching and it still broke! Both ball valves did not look that old. The owner was a bit pissed with me, but they broke so easy.
I am not a fan of plastic ball valves at all in the engine room. I like a metal ball valve, not sure if it helps but If there was an engine room fire I think the raw water hose would melt first. Once the fire is out I would like to be able to close the ball valve to stop any seawater coming in. I am not confident that a plastic ball would survive an engine room fire? Just my thoughts.
Cheers

I'm not sure what grade of PVC the ball valve is. When I google it ( BII 0929NL ) it says it's suitable for marine use and that it's good to 150 PSI.

Since it's mounted about 16 inches away from the engine, if it melts, then I have some real serious issues and the comfort of using a bronze ball valve instead, is not likely to pop to mind at that point.

If I have a fire, I'm hoping my Fireboy system will kick in. If it didn't and the PVC ball valve burst, then I'm thinking having 15 gallons of fresh water in the engine room might not hurt.

[seatotaler]

Originally Posted by Jetx

This... around minute 4:15... is interesting. Less expensive than bronze (still much pricier than PVC), and approved for below the water line. Note that the valve threads are either NPS or BPS, depending on the model, so you do have to buy the Trudesign threaded hose adapters also.

https://youtu.be/HAbvFl-m-Ac

Wow! That's a pretty cool ball valve. However I found a Canadian supplier and a 1 1/4" valve is $132.00 So it's actually much more expensive than Bronze

[boom23]

Originally Posted by seatotaler

I'm not sure what grade of PVC the ball valve is. When I google it ( BII 0929NL ) it says it's suitable for marine use and that it's good to 150 PSI.

Since it's mounted about 16 inches away from the engine, if it melts, then I have some real serious issues and the comfort of using a bronze ball valve instead, is not likely to pop to mind at that point.

If I have a fire, I'm hoping my Fireboy system will kick in. If it didn't and the PVC ball valve burst, then I'm thinking having 15 gallons of fresh water in the engine room might not hurt.

If you have a fire, it will probably happen when you are operating the boat. So, the thru-hole valves will be open. I would not risk burning to close the valves. So, chances are that metal valves will be left open and plastic valves might melt. Not much difference in this worst case scenario.

In my case, the Amel engine room is watertight and has an automatic fire extinguishing system (which will hopefully work). If I remember correctly, I also have a hole to use a manual fire extinguisher.

Just thinking aloud...

[seatotaler]

Originally Posted by boom23

If you have a fire, it will probably happen when you are operating the boat. So, the thru-hole valves will be open. I would not risk burning to close the valves. So, chances are that metal valves will be left open and plastic valves might melt. Not much difference in this worst case scenario.

In my case, the Amel engine room is watertight and has an automatic fire extinguishing system (which will hopefully work). If I remember correctly, I also have a hole to use a manual fire extinguisher.

Just thinking aloud...

The hole for a fire extinguisher is good food for thought. However in order for me to determine if I had a fire in the engine room, I'd have to lift a floor section in my Salon. Which would Fuel the fire with oxygen. But,,,, if I closed the floor section immediately and stuck a fire extinguisher through a hole, it might make a difference, assuming my Fireboy hadn't kick in for whatever reason. My engine room is about 12 feet by 12 feet with 2 engines. But I could maybe rig up a conduit going from that hole that would "Y" so the blast might go towards each engine.
Just thinking aloud
I realize this is getting a little off topic but any thoughts towards addressing safety is always a good thing.

[seatotaler]

Originally Posted by boom23

I am not an expert but this is what Amel is doing and I trust their experience. The intake in the picture is the main/only raw water intake on the Amel 50 and it is oversized. I have not seen how the hull drains are constructed, on the inside of the hull, but I assume they are similar.

From the outside of the hull, you only see a hole.

I'm just trying to understand your pictures Boom23. So is that plastic ball valve actually screwed into the molded fibreglass round inlet in the hull? Is that the sea strainer in the grey plastic container above the valve?