Groco Bronze Thru-Hull Fittings are threaded with NPS (straight) male pipe thread, and are for use with Groco Seacocks or with any product with straight female pipe thread.
Groco Bronze Thru-Hull Fittings are the best choice for below-the-waterline use. They are supplied complete with a bronze locknut or they may be threaded directly into a compatible seacock.
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how long are the threads on the 2 inch
JD Tech Team
What type of bronze is used in the through hull fitting?
Marine silicone bronze.
JD Tech Team
Are there combination thru hulls?
yes the best you can buy.
I don't know what is meant by "combination", so I cannot help you.Rick
dont understand the question
How long is thread section (allowable hull thickness) on 1/2 inch Groco?
Go to the Groco web site. It has all dimensions for each of their products.
According to the 2014 Groco catalog pg 29 it is 2.2".
I have already installed my fitting, but I can say that my overall hull thickness is approximately 1" to 1-1/16". Once the fitting was tightened against the hull, there was enough thread for a 90-deg female pipe ell with threads to spare. If your customer would like to know more precisely, I can measure the exposed threads after all the fittings were assembled.
Belay last answer I DID not buy the 1/2 inch model I had 1 /1/2
Been awhile since I installed my through hull, having said that I own a Nauticat 38 with a thick hull. Plenty of thread left over to attach a seacock
What is the length of the threaded part of the 1-1/4" & 1-1/2" thru hull fittings? I have an 1-1/2" thick hull and I'm using a 3/4" plywood pad.
The 1-1/4" thread length is 2.9 inches the 1-1/2" is 3.15 inches.
I am afraid I cannot help you. I still have not received my order. It is lying at customs in Malaysia and I am back in South Africa. I will be there at the end of August to sort it out and I will be able to answer your question when I get my fittings.Regards
I don't have that boat any longer. The ones I have on my current boat are SS, but for a raw water pickup, you would be better with these Bronze connections. I believe you won't have a problem at all with these because they are threaded from top to bottom. You should have more than enough space to do what you want...
What type of sealant is best for bronze thru hull fittings with a fiberglass hull ???
Underwater silicon or poly sulfide caulk will work.
I believe this is one of the very few applications where 3M 5200 is a good choice.
I am going to use 3M 4200 for all my thru-hull fittings and portholes, all of which I am replacing and re-installing. My hull is 3/4 inch marine plywood covered with fiberglass, a Newporter 40. Wood or fiberglass does not make a difference with regard to the sealant. The main thing is a good backing plate glassed or epoxied in place and thick enough to accept the mounting screws without perforating the hull. There are several on-line instructional videos on installing seacocks. Good luck
I would guess 5200 but I have a wood boat. I had to make a wrench to reach the nut tru a small hole and several inches of ceiling (hull liner to your chlorox people) and frames. I heated a piece of PVC pipe in the oven (don't recall temperature) and forced in over the nut and let it cool. That took a lot of torque without stripping.
Is the inner diameter of the 3/4" thru-hull less than or equal to 11/16ths?I am looking to add threads all the way through the interior of one ofthese brass thru-hulls. Specifically, I want to take a thru-hull with3/'4" NPS threads on the exterior (I'm looking at the TH-750-W), andadd 1/2" NPS threads to the interior. Is there enough material to do this?I believe the hole needs to be a clean, reamed diameter of 11/16ths(and not a 64th smaller) to accommodate being tapped with 1/2" NPSfemale threads.Thanks!Justin Roettger
I can't answer this absolutely as I have no way to make the measurement and no data sheet. Looking at a dimension table for piping, if the thru-hull is sch 40 or 80 dimensioned, the ID is likely 0.824 or 0.742. Only if its sch 160 (unlikely) would the ID be small enough to work. If you aren't attaching a valve to the end of the thru-hull, then perhaps a coupling and reducing bushing could be obtained. This could be problemmatic as the thru-hull is straight threaded and your plumbing fitting is tapered thread. As I used a valve on my thru-hulls, I had no difficulty attaching whatever fittings I needed and would recommend that as the easiest path forward.
specifically i can't say because I got an inch and a quarter fitting. But i can tell you it is thick and robust.
what is the diameter dimension ID OD ?
The 1" thru-hull fitting should have an O.D. of 1.315 inches. I am getting this from the ANSI standards. Keep in mind that the thru-hull threading is straight and not tapered like pipe thread. This works fine if threaded into a proper thru-hull valve. I used a Buck Algonquin 1" bronze ball valve to connect to the thru-hull fitting. Using an ordinary hardware store valve will not work. There is a excellent article in Wooden Boat Magazine a few issues back about installing through hulls if you want more information.I am not sure but I am guessing that I used a 1-3/8 inch hole saw to cut through the hull. I would recommend a trial cut on a scrap to verify that size is large enough.The I.D. I can not provide as the fitting is not accessible and I have no record. Its going to be close to 1 inch.Ralph (Zakkendrager on Wooden Boat forum)
You don't mention which size Groco Thru-hull fitting you are asking about. In general, thru-hull sizes are the NPS thread size. So, a 3/4" thru-hull will have 3/4" NPS thread size on its body. If you need a specific ID or OD, I suggest looking up NPS thread sizes. For example, a 3/4 NPS will have an OD of 1.05 inches. Hope this helps.
Go to groco dot net and you can get the specifics of each fitting dimension.
the hole size is 1-1/8'' and the transom is 2" so will this item fit my boat? hop so
I think it is too long, 3".
It depends. If there is a 2" diameter hole in the transom, I would say that a thru-hull with a 1-1/8" diameter is not going to make a good installation. If it were me, I'd plug the 2" diameter hole properly with wood and then bore the proper size hole.But if you are saying the transom is 2" thick, then a thru-hull fitting of the correct length will work. The hole should be only slightly larger than the fitting. But the fitting needs to be long enough to have a backing block on the inside and to attach the valve with sufficient threads engaged in the valve. Its normal to have to cut the fitting to length.There was an excellent article on installing thru-hull fittings in the last issue of Wooden Boat magazine.
juanita, depends on which one or size valve. The size hole is for the corresponding fitting. I believe your 2" measure is the thickness??? This is not really related here. Whichever fitting u purchase, they will have a recomendation of hole size to drill. I reccomend u " Compass Marine projects by Maine sail and choose the job for thru hull install, has easy instructions and pictures, good luck...Red
is this available in 1" thread with 2-3/4 o.d. flange ?
Yes I believe they are available in all standard pipe sizes from 3/4" up and with 2-3/4" flange on the 1" thru-hull
High quality. No issues.
This was a quality piece of hardware.
This item was used for the bilge pump discharge on a 33-ft sailboat.
High Quality - Competative Price
The internal "wrench tabs" are not as large as competitors, and should be increased in size during the casting process.
Good quality fittings
These are well made thru hull fittings. They thread easily into Groco and other brands of seacocks. It makes for a good installation.