Gate or ball valve

Brisyboy · Oct 22, 2015

Our new to us boat has a mixture of both - looks like the PO was in the process of changing from gate to ball although all look new.
From my point of view a ball valve is preferred as its a visual check to see whether its open or closed - a gate valve needs turning to check.

I hope this isn`t like an anchor preference question but is there any technical/functional benefit in either style valve.

menzies · Oct 22, 2015

Get rid of all the gate valves ASAP. Not only are they prone to corrosion and freezing, but if you get a little stone or anything else in there it will block it and stop it from closing. Very dangerous. IMHO they should stick to using them below your home toilets.

DavidM · Oct 22, 2015

Ball valves have largely replaced gate valves in the industrial world, at least for small, <6" applications. Ball valves seal against a polymer seat, usually either Nylon or Teflon. Gate valves seal against a machined surface which can get buggered up and leak, or get blocked from sealing by crap in the seat.

So go with bronze ball valves in seawater service. Brass is ok for fresh water or fuel systems.

David

kchace · Oct 22, 2015

Gate valves have serious drawbacks when used in boats. No gate valves.

Ken

Cyclone · Oct 22, 2015

Greeting. Yes ball valves, however ensure the the valve is left partially open/closed during winter. Moisture can remain and will freeze in the value.

Steve · Oct 22, 2015

Ball, it's unanimous, maybe a first for the forum!

boatpoker · Oct 22, 2015

Gate valves do not meet ABYC Standards and will be written up by any surveyor worth his salt.

BerettaRacer · Oct 22, 2015

Actually, for true engineer purposes, they each have different characteristics.
A gate valve will allow full flow of pipe diameter with no restrictions, but should not be throttled as it causes erosion of gate and seat.
A globe valve does the opposite, it has a built in restriction, it is designed to allow good flow (bottom to top) but not great, but will throttle with no issue.
A ball valve is somewhere in between, the ID of the ball is less than the ID of the pipe, (with the exception of special full flow valves), and they will throttle to a point just not as a fine adjustment as a globe valve.
Butterfly valves have the restriction of having the disc in the flowpath, but they will throttle too. Work well with flange plumbing.
Each has there purposes, not really a one size fits all.

menzies · Oct 22, 2015

BerettaRacer said:
Actually, for true engineer purposes, they each have different characteristics.
A gate valve will allow full flow of pipe diameter with no restrictions, but should not be throttled as it causes erosion of gate and seat.
A globe valve does the opposite, it has a built in restriction, it is designed to allow good flow (bottom to top) but not great, but will throttle with no issue.
A ball valve is somewhere in between, the ID of the ball is less than the ID of the pipe, (with the exception of special full flow valves), and they will throttle to a point just not as a fine adjustment as a globe valve.
Butterfly valves have the restriction of having the disc in the flowpath, but they will throttle too. Work well with flange plumbing.
Each has there purposes, not really a one size fits all.

That's all good.

But which one would you put in your boat?

AusCan · Oct 22, 2015

BerettaRacer said:
Actually, for true engineer purposes, they each have different characteristics.
A gate valve will allow full flow of pipe diameter with no restrictions, but should not be throttled as it causes erosion of gate and seat.
A globe valve does the opposite, it has a built in restriction, it is designed to allow good flow (bottom to top) but not great, but will throttle with no issue.
A ball valve is somewhere in between, the ID of the ball is less than the ID of the pipe, (with the exception of special full flow valves), and they will throttle to a point just not as a fine adjustment as a globe valve.
Butterfly valves have the restriction of having the disc in the flowpath, but they will throttle too. Work well with flange plumbing.
Each has there purposes, not really a one size fits all.

Agree with most of the above, with a one exception.
Most ball valves are full flow, and should not be used partially open to throttle flow in most situations. This can damage the face of the teflon seats.

I would stick to ball valves on a boat in the majority of applications. Plug valves are also fine, but they may need to be oversized to ensure their ID is large enough to handle the flow.

Needle valves (very restrictive) are sometimes used on hydraulic systems at bleedoff points or to isolate pressure gauges.

There are generally two types of gate valves. The cheap throwaway type from the hardware store, and severe service high pressure type. Neither have any use on a boat.

Brisyboy · Oct 23, 2015

Steve said:
Ball, it's unanimous, maybe a first for the forum!

Steve, I haven`t been a member long enough to comment but it sure looks like it.

I thought Berettaracer and Menzies were going to offer some opposition but no, they only gave some options - I took their posts as a vote for ball valves.

So, ball valves it is - stainless?

BerettaRacer · Oct 23, 2015

Brisyboy said:
Steve, I haven`t been a member long enough to comment but it sure looks like it.

I thought Berettaracer and Menzies were going to offer some opposition but no, they only gave some options - I took their posts as a vote for ball valves.

So, ball valves it is - stainless?

In your original post your never said what its use, so I can't offer an opinion as to type, so I just gave different design purposes.
Purpose = type.
Sea water inlet is one type of valve, sea water outlet can be a totally different type.
I have flanged, butterfly valves on my inlets to allow full flow in, but globe valves on my gear box overboards so I can throttle to adjust gearbox oil temp.

psneeld · Oct 23, 2015

Groco Full Flow In-Line Ball Valves (IBV series)

Groco Full Flow In-Line Ball Valves (IBV series)

boatpoker · Oct 23, 2015

Flanged bronze or in some (few) cases Marelon.
Suggest you read Rod Collins superb article with great photos on Seacock installation.

HiDHo · Oct 23, 2015

If monies not a problem I would use Spartan bronze sea cock valves. I like the wide flange on them and the boat will wear out before these valves do

Bacchus · Oct 23, 2015

Steve said:
Ball, it's unanimous, maybe a first for the forum!

Wow - hard to get a concensus here but I belive you have done it.

Caution that has been mentioned is material - also be aware of different threads if this is a through hull / seacock application. A good resource is RC's Compass Marine How To Articles specifically the one on Through Hulls & Seacocks.

FF · Oct 29, 2015

The hassle with gate valves is the stem is usually made of "free machining" brass.

The brass de zincifys and you loose controll of the valve.

Ball valves come in crap and good versions , be sure the open diameter thru the ball is the same size as the lines ID that are connected to it.

tallswede · Oct 29, 2015

I have only one gate valve on my boat. It is on the engine coolant to the water heater coil. I use it to restrict flow through the heater coil. I feel this is not too severe a service for this valve due to the antifreeze solution in the cooling system. Other through hulls etc. should all be ball valves for quick reliable operation.

Kevin

ulysses · Oct 29, 2015

BerettaRacer said it all and evidently knows his valves. Different valves for different purposes. As he alluded to- do not use a valve not designed to throttle in a throttling position. Fully open or completely closed on ball valves and gate valves. In a waste water situation a plug valve maybe a viable option that has not been mentioned. In regards to potential freezing, my proven technique is to always operate the valves in a position below 28 degrees latitude in the winter months.

Irish Rambler · Oct 29, 2015

tallswede,
I'm a bit curious as to why you'd wish to restrict the water flow to your water heater coil, do you mean the domestic Calorifier ?
The water can only go to engine temp so why restrict it ? if you wish to keep the domestic tap water temp down to prevent scalding I respectfully suggest you fit a mixer valve unit on the hot water outlet, it will prevent scalding and your hot water in the Calorifier lasts longer

FlyWright · Oct 29, 2015

I replaced the gate valves on my fuel shutoffs with bronze ball valves. I still have a couple of gate valves on my freshwater and RW washdown systems that I believe are fine for their purpose. One is at the freshwater washdown spigot. Another is at the aft RW washdown spigot. The third is at the water heater drain. It came installed on the water heater.

Northern Spy · Oct 29, 2015

tallswede said:
I have only one gate valve on my boat. It is on the engine coolant to the water heater coil. I use it to restrict flow through the heater coil. I feel this is not too severe a service for this valve due to the antifreeze solution in the cooling system. Other through hulls etc. should all be ball valves for quick reliable operation.

Kevin

Gate valves aren't typically used for throttling as the gate is wedge shaped and when in the partially open the flow past will rattle the gate in the seats. On cheap small diameter valves (and big expensive ones too), this will often lead to the gate to stem connection wearing and the gate liberating itself from the stem. If the stem is in the vertical position, the gate drops and shuts off flow.

In your case, not a big deal. But a good reason not to use them "improperly" in a critical service.

Larry M · Oct 29, 2015

FF said:
The hassle with gate valves is the stem is usually made of "free machining" brass.

The brass de zincifys and you loose controll of the valve....

On an old gasser we had, the raw water control was a gate valve. All of a sudden one day we lost cooling. I went to shut the gate valve thinking I had clogged the raw water screen. The valve kept turning in my hand until I realized the stem had separated from the gate and it dropped into the closed position. I had to remove the gate to get back to the dock for a haul out the next day to install a proper ball valve.

ulysses · Oct 29, 2015

Yep they will do that or if throttled way down actually cut a groove through the gate or body of the valve. One advantage of a gate valve, especially on a pressure system is that it reduces water hammer in that it opens slower. Once again different valves for different purposes.

Gate or ball valve

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