According to their tech rep the balls in Groco's are actually red brass balls not the same inexpensive yellow brass that home centers sell.
While red brass is slightly different in composition than the 85-5-5-5 bronze used in the bodies red brass & 85-three-5 bronze are very close galvanically speaking. I'd be very surprised if the balls in the Apollo's are actually teh same composition as the valve body but with Apollo, and their engineering, anything is possible. There are many forms of brass, red brass and bronze all referred to as bronze or even brass.
I have yet to have one of my Groco's show any signs of corrosion, not that they won't. I actually had one off last year that was 7-8 years old and the ball looked brand new and was un-pitted..I can't recall from the log when this one was exactly replaced. The PO installed it while off cruising.
The photo's below are of a one year old +/- yellow brass Home Depot ball valve also installed by the previous owner. It was installed on the same boat as the Groco BV pictured above and in use during the same time period. When I asked this seasoned boating veteran why he used a ball valve from Home Depot he said; "it was only in a pinch while coming up the ICW but after it was installed I forgot to replace it with bronze one".
This "Home Depot" valve was in use for about 8-12 months, of total in water time, and the ball, inside the valve, is completely gone, as in not there & corroded away. This valve was literally weeks away from catastrophic failure of the boat sinking type. It was seriously dezincifying as noted by the pinkish coppery color both inside and out. I can only imagine how high the zinc content in that valve was..?
Home Depot Special:
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, at least IMHO.
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 most flanged seacocks as measured by cross sectional thickness.
#3 Saves money down the road because the valve replacement, which is almost 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 seacock/valve replacements far less expensive and considerably less invasive and time consuming.
#7 Ball valves 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 or plastic 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 them many times, 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.
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 other 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 so long as corrosion does not take over. I have also seen 30+ year old tapered cone seacocks still operable after re-lapping such as Blakes or Spartan's..
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 (Catalina). My boat was quickly hauled and every seacock converted to flanges and through bolts, though well before the flanged adapter became available..
Hamilton Marine is a great source for the ball valves and flanged adapters as is Jamestown. Using the flanged adapters allow you to choose Apollo/Conbraco vlaves if you want or use the Groco's..
Just another thought...
