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Sailorguy · 29-10-2009, 08:10

I installed GROCO BV Series Full Flow Ball type sea cocks: the ball and stem are 316 SS and the body is bronze casting. Others that I had talked to that had installed chrome plated bronze ball valves such as Apollo brand had reported pitting which caused leakage.

Steve

cburger · 29-10-2009, 08:16

Ditto that Steve

Sailorguy · 29-10-2009, 08:21

Add'l comments: the Groco full flow "inline" type valves use a chrome platted brass ball; these are designed to screw onto a thru hull vs. the sea cock which is designed to be thru bolted. I would rec'd staying away from the inline version. The sea cock adds a level of security and longevity not found in the other....IMHO.

Steve

Maine Sail · 29-10-2009, 09:57

Quote:

Originally Posted by aboutgone

I went with Conbraco Apollo flanged three hole valves and thru hulls...wanted to go with the flanged adapter plate which is NPS,but all the ball valves i found were NPT. I cut epoxy fiberglass phenolic backing plates an inch bigger than the valve base, shaped them to the hull and 5200 was applied to all surfaces....nice to get rid of thoes huge conical sea cocks on my 30 year old CSY.....wanted to go with Marelon but Forespar didn't make thru hulls long enough for the thick glass hull on the CSY's (2 1/2 '').........Ed

You probably should have read or researched a little further and you would have seen they do exactly as you wanted them to do.

The whole idea of the Groco flanged adapter is that the threads on the top of the flange, or inside of the hull, are NPT (tapered cut) just like a standard ball valve is.

The threads on the bottom of the flange, or facing the outside of the hull, are NPS (straight cut) to match the straight threads of a thru-hull.

The flanged adapter was invented for a number of reasons all of which make it one of the best inventions as of late for seacock technology.

Flanged Adapter Benefits:

#1 Matched threads between BV and adapter and thru-hull and adapter.

#2 Stronger than slapping a BV on a thru-hull and as strong as a flanged seacock as measured by cross sectional thickness.

#3 Saves money down the road because the valve replacement, which is always the first to fail, takes less than five or ten minutes and can be done in the water any where.

#4 Allows for easier plumbing configuration when low internal height to cabin sole etc. limit the total valve height.

#5 Can be permanently mounted to the hull and allows easy valve replacement in any location in the world without requiring a haul-out. NPT ball valves are easy to find anywhere in the world, even in remote locations.

#6 Makes future valve replacements far less expensive and considerably less invasive and time consuming.

#7 BV are less expensive than flanged seacocks so the second time you change a BV you are way ahead financially.

#8 Carrying one or two sizes of spare BV's, as a world cruiser, is much cheaper than carrying spare seacocks.

#9 Spare BV's can be used in a pinch for far more on your vessel than can a spare flanged seacock. A 3/4" BV is a good spare to have but a spare 3/4" flanged seacock is only a spare seacock.

#10 In a remote location, when you can't find a replacement seacock, nor a place to haul out or beach the vessel and wait for a tide, you can use any, brass, stainless, bronze or even copper NPT/NPT ball valve to get you back in business. Of course if you use sub par metals be sure to change it back out when you get to a local where bronze valves are available. If a flanged seacock fails to open or close you will need to replace the entire unit not just spin a valve off and replace it.

The #1 failure of BV's, as I have experienced, is the ball and seats not corrosion of the bronze body or thru-hull. When folks do not open or close the valves enough growth attaches to the closed ball and when opened it digs up the phenolic valve seat or scores the ball. The same type of scoring can happen on tapered cone valves, seen it, and repaired it, if not used enough.

Having replaced hundreds of seacocks I can count half the fingers on one hand the number of times I saw a thru-hull that was not reusable if it had not been destroyed by removal due to 5200 or similar. I have seen 35+ year old thru-hulls in perfect condition on numerous occasions. If you've had enough corrosion to destroy your thru-hull then your prop, prop shaft, rudder shoe or strut will also be quite damaged.

I have not yet seen a 35 year old BV, in the marine environment, still operable. I'm sure there may be some out there that still work but I have not come across one. On the otehr hand I have seen hundreds of re-usable thru-hulls at the 30-35 year mark making them almost permanent or at least multiples more permanent than a BV. I have also seen 35 year old tapered cone seacocks still operable after re-lapping.

It is almost always the BV that fails and not the thru-hull unless it was broken off because it was not installed into a flanged seacock or flanged adapter.

I cracked a thru-hull on my own boat in a storm. This was a valve on a thru-hull with no flange. My boat was quickly hauled and every seacock converted to flanges and through bolts..

Cheechako · 29-10-2009, 10:06

My concern with the threaded "take apart" version would be that it is no different than just putting a ball valve on the stem of a thru hull...... the stress in trying to open/close a frozen valve is still on the threads (thinnest part of the assembly) rather than on the triangular base.... With a normal seacock it is distributed to the base.....
Not sure what Groco is doing now days. They never were as good as Wilcox Crittendon, who no longer exist. Groco is chinese now arent they? The real question is are they controlling their quality well enough if chinese? or living off their name? The key to Chinese quality is setting an expectation of what you want and monitoring it until they "get it". If Groco is not doing Mettalurgical analytic samples... who knows what the stuff is.... Spartan stuff is still made in the NE US isnt it? I would definitely give them a look.... They make some nice stuff.

Maine Sail · 29-10-2009, 10:20

Quote:

Originally Posted by Sailorguy

Add'l comments: the Groco full flow "inline" type valves use a chrome platted brass ball; these are designed to screw onto a thru hull vs. the sea cock which is designed to be thru bolted. I would rec'd staying away from the inline version. The sea cock adds a level of security and longevity not found in the other....IMHO.

Steve

I understand many are not aware of the flanged adapter. Inline BV's do not have to thread only onto a thru-hull, in fact doing so is usually a thread mis-match. Inline valves can be threaded onto a flanged adapter too.

Below is a flanged adapter:

P.S. I have two flanged Apollo seacocks that were installed in 2000 for my cockpit scuppers. They have stainless balls and are very tough to operate at this tiem and lube has done noting to help. These are my final two non-flanged adapter seacocks.. I will be replacing them this winter with Groco flanged adapters so that in another ten years I am not doing major surgery to replace the valves..

Hope the photo helps show how a flanged adapter works.

cburger · 29-10-2009, 10:40

Quote:

Originally Posted by Cheechako

My concern with the threaded "take apart" version would be that it is no different than just putting a ball valve on the stem of a thru hull...... the stress in trying to open/close a frozen valve is still on the threads (thinnest part of the assembly) rather than on the triangular base.... With a normal seacock it is distributed to the base.....
Not sure what Groco is doing now days. They never were as good as Wilcox Crittendon, who no longer exist. Groco is chinese now arent they? The real question is are they controlling their quality well enough if chinese? or living off their name? The key to Chinese quality is setting an expectation of what you want and monitoring it until they "get it". If Groco is not doing Mettalurgical analytic samples... who knows what the stuff is.... Spartan stuff is still made in the NE US isnt it? I would definitely give them a look.... They make some nice stuff.

All very good points, Spartan high quality yankee construction.

**s/v Jedi** · 29-10-2009, 10:42

Okay, I am convinced... see, I change my mind sometimes ;-)

Now the only possible problem left is when you get a valve or thru-hull fitting with that nasty British thread, BSP or whatever they call it. Many valves sold in places like Trinidad have that....

Edit: no guys, I think Mainsail found that the wall thickness of the flanged adapter equals that of a seacock.

cheers,
Nick.

Maine Sail · 29-10-2009, 11:34

Quote:

Originally Posted by s/v Jedi

Edit: no guys, I think Mainsail found that the wall thickness of the flanged adapter equals that of a seacock.

cheers,
Nick.

Yup! Theories are good but I always do the dirty work..

For this examination I wanted to know the actual wall thickness of a standard 1" thru-hull fitting. The fitting is a common bronze Conbraco/Apollo 1" thru-hull which I purchased right off the shelf at Hamilton Marine.

In this photo I am measuring the overall thickness of the thru-hull.
It measured in at 2.99 millimeters thick.

To accurately measure the nominal wall thickness of this 1" thru-hull I first needed to measure the thread depth that had been cut into it. I used my calipers to figure out the depth of the thread cut.

The threads cut into the the 1" thru-hull pictured above were 1.45mm deep on that 1" thru-hull fitting.

If you subtract the 1.45mm thread cut from the 2.99mm overall thickness you get the remaining nominal wall thickness of 1.54 millimeters.

Yes, you read it correctly, the nominal wall thickness on this very popular Apollo 1" bronze thru-hull fitting is roughly the thickness of an average penny at only 1.54 millimeters.

In the interest of fairness I also wanted to measure the total wall thickness of the flange, at the top threads, to compare it to the 1" thru-hull nominal wall thickness. I understand I'm not comparing two 1" or two 3/4 inch fittings but the points remain the same and the wall thickness is what I am trying to get at. This3/4 flanged adapter fitting measured an overall thickness of 4.04 millimeters and a thread depth of 1.26mm millimeters. When you subtract 1.26mm from 4.04mm you are left with a total nominal wall thickness of 2.78mm. This makes the thickness, of this 3/4 flanged adapter fitting, at the threads, approximately double that of the 1" Apollo thru-hull fitting, and comparable to the base thickness dimension of a Groco flanged seacock.

In short the flanged adapters are quite robust..

Cheechako · 29-10-2009, 11:50

I like the science and it seems to indicate that they thought about this.... which is very encouraging in these days and times!! However, we can only conclude that in order to get the wall thickness, you now have a 1" thru hull with the inside diameter of about a 3/4" thru hull!..... which is still better than haveing a thickness of a penny I suppose....

Christian Van H · 29-10-2009, 15:01

Quote:

Originally Posted by aboutgone

I...wanted to go with the flanged adapter plate which is NPS,but all the ball valves i found were NPT.

Hi Ed! The Tri-flanged adapters are NPS INSIDE, and NPT OUTSIDE for the correct fit into valves. This feature is really hard to read in their catalog. Look at the drawings in their online catalog: GROCO MARINE PRODUCTS Zoom in on the adapter page and you can see them spelled out...

DOH! I missed the whole second page of this thread and posted the same info as Maine Sail. Sorry!

aboutgone · 29-10-2009, 16:17

I stand corrected.Seems like a much better system... finished them yesterday..but mean time, part of my engine and pre sail check list will include cycling the valves......but when they fail, I will change to the flanged adapters.....Ed