7/8 inch Hose barbs? !!

[Uncle Bob]

Love the earnest suggestions to source and use brass fittings on the water pump">raw water pump. Not on my boat.

[jimbunyard]

Originally Posted by jimbunyard

Just buy a standard 1/2 X 3 bronze pipe nipple for 3.00, cut the threads off one end and screw what's left into the pump. It's very unlikely that you need any kind of barb or retaining mechanism; the friction from the double clamps and the relatively low pressure work in your favor here.

If you're nervous about it, it's easy enough to file a groove or two near the cutoff end for the ID of the hose to bite on, or to put a couple/three drops of solder on the the clamp end of the nipple to give some 'grip'.

...The solution suggested is standard operating procedure, will work as advised and I have done it way too many times to count.

With, I might add, no ill effects and no corrosion (if that's what "not on my boat" means). Not to be too earnest...

Originally Posted by Uncle Bob

Love the earnest suggestions to source and use brass fittings on the raw water pump. Not on my boat.

Bronze is not brass, though some brasses are almost bronze and are somewhat suitable for marine use. Unless the source is known and trusted, hardware store brass should be not assumed to be red, naval or admirality brass, which are generally suitable for many marine applications.

Bronze, copper alloyed with tin, (at least for saltwater-specified pipe fittings) is the same whether one pays 3.00 or 140.00. Since the purpose of the original post was to find an effective alternative to paying the higher price, and that's what several did, it's hard to see the relevance of your post.

Or perhaps you just own Westerbeke stock...

[Compass790]

Originally Posted by s/v Jedi

So you guys think a hose clamp will keep a 7/8” hose on a 1/2” nipple? That’s 3/8” difference...

I would take a bronze adapter from 1/2” male to 3/4” female and do the same with a 3/4” nipple, incl. brazing a bead/lip on the end.

Do you sir have a vernier caliper or a micrometer?
I have a successful mating between an 1&1/2" sched 10 pipe on exhaust elbow & a 2" exhaust hose, admittedly with the help of silicone to make up the difference , only held on by a single hose clamp. It's only worked for 7 years part time cruising. It's only an 8hp motor I should point out.
Perhaps you are confusing O.D & I.D. or NB?
Jim Bunyard is giving the OP good advice IMO.
But he can choose to get reamed if he wishes.

[Nord Sal]

Hey Cheechako (nice Alaskan name BTW) I misread your post using the nipple. That is a simple fix. I was envisioning that you were just talking about cutting down a hose barb. Thanks to Jimbunyard too for reiterating and to get it through my thick canium.


So, I've now just spent a few minutes with google looking for 1/2" bronze pipe nipples. I'm not having any luck yet. I thought I located some right away when I found "Bronze Pipe Fittings" in a Marine supplier's site . . ., but when I read their product description for "bronze pipe nipple" it's qualified at the bottom of the page with this note: "Note: We cannot source bronze nipples, and so we offer red brass instead. Due to the difference in corrosion resistance between these two metals, using them together in a below-the-waterline saltwater environment is not recommended. Instead, we recommend using tail pieces and hose."


Well, that was a little discouraging. I'm not finding anything bronze in the size I need and am beginning to wonder if it exists. Might Copper be an appropriate material?

[eceavchss]

My Universal M35B has a 1/2NPT x 7/8 hose fitting on the raw water pump. The P/N is 030183 and they are under $25.

[Cheechako]

Originally Posted by s/v Jedi

So you guys think a hose clamp will keep a 7/8” hose on a 1/2” nipple? That’s 3/8” difference...

I would take a bronze adapter from 1/2” male to 3/4” female and do the same with a 3/4” nipple, incl. brazing a bead/lip on the end.

NO, a 1/2" nipple is spec'd at .84 " OD. Pipe is spec'd for ID.
7/8" = .88 diameter.
It's close.
I'd probably try it, clamp the hose on and physically try to pull it off to see. Or get a 7/8 hose that is tight on that fitting, some hoses are very tight..

OP: the world of boats want double clamps on everything, unfortunately the manufacturers never got the memo and many fittings don't allow double clamps. Spend money on a great single clamp if necessary.

[Cheechako]

Originally Posted by Nord Sal

Hey Cheechako (nice Alaskan name BTW) I misread your post using the nipple. That is a simple fix. I was envisioning that you were just talking about cutting down a hose barb. Thanks to Jimbunyard too for reiterating and to get it through my thick canium.


So, I've now just spent a few minutes with google looking for 1/2" bronze pipe nipples. I'm not having any luck yet. I thought I located some right away when I found "Bronze Pipe Fittings" in a Marine supplier's site . . ., but when I read their product description for "bronze pipe nipple" it's qualified at the bottom of the page with this note: "Note: We cannot source bronze nipples, and so we offer red brass instead. Due to the difference in corrosion resistance between these two metals, using them together in a below-the-waterline saltwater environment is not recommended. Instead, we recommend using tail pieces and hose."


Well, that was a little discouraging. I'm not finding anything bronze in the size I need and am beginning to wonder if it exists. Might Copper be an appropriate material?

On an engine I would probably use brass and feel OK, but the engine is cast iron, you can get iron or steel nipples if you want.
Marine sources should have Bronze though...? But there's a lot of semantics going on in the sale of Bronze, brass, red brass etc now days for sure... making it hard to know what you are getting.

"Red brass is a type of bronze – an alloy of copper, tin, and zinc. Proportions vary but 88% copper, 8–10% tin, and 2–4% ZINC is an approximation. Originally used chiefly for making guns, it has largely been replaced by steel.

Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals (such as aluminium, manganese, nickel or ZINC) and sometimes non-metals or metalloids such as arsenic, phosphorus or silicon."

[GordMay]

Originally Posted by Nord Sal

... when I read their product description for "bronze pipe nipple" it's qualified at the bottom of the page with this note: "Note: We cannot source bronze nipples, and so we offer red brass instead. Due to the difference in corrosion resistance between these two metals, using them together in a below-the-waterline saltwater environment is not recommended. Instead, we recommend using tail pieces and hose."
Well, that was a little discouraging. I'm not finding anything bronze in the size I need and am beginning to wonder if it exists. Might Copper be an appropriate material?

Originally Posted by Cheechako

... "Red brass is a type of bronze – an alloy of copper, tin, and zinc. Proportions vary but 88% copper, 8–10% tin, and 2–4% ZINC is an approximation. Originally used chiefly for making guns, it has largely been replaced by steel...

Can you check their composition?
Red Brass/Gunmetals:
Gunmetals, more prevalent in Europe and sometimes called “red brass” in the United States, are tin bronze castings that have been widely used in shipbuilding and marine engineering. The addition of a small amount of zinc improves castability. The alloys are resistant to corrosion from steam and salt water and are not prone to dezincification, stress corrosion, crevice corrosion or pitting. Gunmetal alloys are used to make steam and hydraulic castings, valves, pump parts, steam fittings, gears, bearings, statues, and small objects such as buttons.

Modern admiralty gunmetal is composed of 88% copper, 10% tin, and 2% zinc.

[jimbunyard]

Or you could use a 316 ss nipple, the two materials are close enough on the nobility chart to not make a difference.

Or you could use an FF-500, manufactured by Groco (so you can be assured of its 'bronzeness') and available ex-stock from many suppliers for about 10 bucks.

https://www.fisheriessupply.com/groc...-bronze-ff-500

The dimensions are a little off, but should be close enough to work in your application.

[Cheechako]

Originally Posted by jimbunyard

Or you could use a 316 ss nipple, the two materials are close enough on the nobility chart to not make a difference.

Or you could use an FF-500, manufactured by Groco (so you can be assured of its 'bronzeness') and available ex-stock from many suppliers for about 10 bucks.

https://www.fisheriessupply.com/groc...-bronze-ff-500

The dimensions are a little off, but should be close enough to work in your application.

As I remember (dont take it to the bank!) those Groco nipples are a little large on the barb end. it might work!

[Compass790]

Originally Posted by jimbunyard

Or you could use a 316 ss nipple, the two materials are close enough on the nobility chart to not make a difference.

Or you could use an FF-500, manufactured by Groco (so you can be assured of its 'bronzeness') and available ex-stock from many suppliers for about 10 bucks.

https://www.fisheriessupply.com/groc...-bronze-ff-500

The dimensions are a little off, but should be close enough to work in your application.

Wot he saidx2

No problem with 316 ss nipples

[s/v Jedi]

Okay diameter sound great... are there bronze nipples available?

[Nord Sal]

Originally Posted by eceavchss

My Universal M35B has a 1/2NPT x 7/8 hose fitting on the raw water pump. The P/N is 030183 and they are under $25.

That might work. I see that part 030183 is an ell fitting and my current arrangement is straight. I will have to check the system out to see if that will work. I don't want an ill fitting ell fitting, sorry, I couldn't resist.


I'd use a 316 SS hose barb in a minute if I could find one in 7/8".


The Groco might work. It does bug me to have to knowingly use a wrong size to get a decent and reasonably priced fitting. I don't want to encourage any weeping or leaks.


My seawater pump is a Sherwood F85. I looked it up and it and it shows it is bushed down to 1/2" ports from 3/4", so i might be able to use this fitting PN 36838 if mine is bushed. I found that fitting by searching "7/8 HOSE" on the TOAD site. Westerbeke seems to have a few 7/8" fittings, though I can't find anyone else that does.


For the more machinist orientated, would it be feasible to tap 3/4" NPT threads into the existing pump if it's not bushed or are the 1/2" NPT to close in size? My pump is older and I don't think it has a reducing bushing.

[NCboatrx]

You can buy 7/8" hose barbs from the UK. Here is a link https://www.asap-supplies.com/fittin...nection-404039

[jimbunyard]

Originally Posted by Nord Sal

That might work. I see that part 030183 is an ell fitting and my current arrangement is straight. I will have to check the system out to see if that will work. I don't want an ill fitting ell fitting, sorry, I couldn't resist.


I'd use a 316 SS hose barb in a minute if I could find one in 7/8".


The Groco might work. It does bug me to have to knowingly use a wrong size to get a decent and reasonably priced fitting. I don't want to encourage any weeping or leaks.


My seawater pump is a Sherwood F85. I looked it up and it and it shows it is bushed down to 1/2" ports from 3/4", so i might be able to use this fitting PN 36838 if mine is bushed. I found that fitting by searching "7/8 HOSE" on the TOAD site. Westerbeke seems to have a few 7/8" fittings, though I can't find anyone else that does.


For the more machinist orientated, would it be feasible to tap 3/4" NPT threads into the existing pump if it's not bushed or are the 1/2" NPT to close in size? My pump is older and I don't think it has a reducing bushing.

Let's try this one last time.

OD of any 1/2" pipe is .84" nominal. Bronze, brass, steel, plastic, ss, -- doesn't matter. With that dimension, any 1/2" pipe nipple will serve as an effective 'hose barb' for 7/8" hose. At the pressure it will encounter in this service, it will not "encourage any weeping or leaks" if tightened to normal torque, at the clamps or at the threads.

The FF500 barb is not 'wrong' because it won't work; it's wrong because it is your idea that it's wrong.

It is very likely that changing from a 1/2" pipe size to a 3/4" pipe size on the pump will thin the wall enough for at least a danger of breakage, which will definitely "encourage weeping or leaks".


Westerbeke's knowledge of their market is beginning to show.

Originally Posted by NCboatrx

You can buy 7/8" hose barbs from the UK. Here is a link https://www.asap-supplies.com/fittin...nection-404039

The linked-to fitting hose end is not 7/8", it is 22 mm, or .866162". Strike one. It is brass. Strike two. The thread end is 1/2" BSP, not NPT, which will definitely not seal (unless maybe you epoxy it in place. [Which may "encourage weeping or leaks"]). Strike three, and he goes down swinging...though perhaps there actually is a bronze, 1/2" NPT X 7/8" hose barb on the site.

I didn't look.