Thru-hull fittings - can someone give a measurement?

I've got a job in right now that needs a plastic thru hull fitting (barbed), with the capability of being plugged, with some sort of readily available drain plug. All the fittings seem to be marketed with the hose barb size, but what I'm needing is the ID of the other end of the fitting, so I can match it with the proper plug. Obviously, the easy answer would be to acquire the fitting first, or measure one in the store, but I have to order all items of this nature over the web, as I don't have any decent store selling this sort of item within almost an hour of here, and I would like to consolidate all my items into a single order.

What I need is for someone (or multiple people :lol: ) that happens to have a plastic thru hull within easy reach to measure both the OD of the barb (to determine what size that would be sold as) and the ID of the other end, where the plug would be. I'm probably looking at fittings in the 3/4 - 1 1/8" range, but for the sake of comparison, just about any fitting size should work.

For clarification, we are speaking of fittings like the one in the link. Brand is no matter, but if you happen to know the brand, it certainly wouldn't hurt.

https://www.iboats.com/Seachoice-Th...18062970--session_id.460609314--view_id.47352

If a few of you didn't mind checking either one installed on your boat, or a new one you are about to install in a mod, I would be most grateful. Of the 5 boats on the premises at the moment, and in my supply of various boat parts, there isn't a single thru-hull fitting to be found, believe it or not, and I'm really not thrilled with the idea of a nearly 2 hour round trip just to go measure a plastic fitting.

Thanks,

Dawson

Hi Dawson,

Not sure if this helps or not, but here's the measurements for my two TH Marine (Huntsville, AL) brand thru-hull fittings I bought at Athens Marine:

From the package:

"3/4" straight thru-hull, part number TH-752-DP"
"Requires 1 7/8" hole"
"Fits 3/4" ID hose"

My measurements of TH-752-DP:

- It has 1/2" inner diameter at the barbed end of the fitting

- It has 11/16" inner diameter at the head (boat exterior end of the fitting)

- It has 7/8" outer diameter at the threaded head end
(where the fitting goes through the hull and the nut is screwed on.)

Note: On the above fitting, the diameter abruptly changes from the barbed section to the threaded section of the fitting.

From the package:
"1 1/8" straight thru-hull, part number TH-1202-DP"
"Requires 1 3/8" hole"
"Fits 1 1/8" ID hose"

My measurements:

- It has 1 1/16" outer diameter at the barbed end

- It has 13/16" inner diameter at the barbed end

- It has 15/16" inner diameter at the head
(boat exterior end of the fitting)

- It has 1 3/16" outer diameter at the threaded head end
(where the fitting goes through the hull and the nut is screwed on.)

Note: On the above fitting, the diameter appears to taper gently from the barbed section to the threaded section of the fitting, unlike it's smaller sibling.

Here's a link, Bass Pro Shops sells this brand.

https://www.basspro.com/webapp/wcs/stores/servlet/Product_10151_-1_10001_8029_225003005_225000000_225003000?channel=froogle&mr:trackingCode=1EC798AF-03A7-DF11-904F-002219319097&mr:referralID=NA

I hope this helps, feel free to call me if you have any questions.

Dave

Dawson,

Something that occurred to me today is why make an external plug when you can insert an inline plastic ball valve and do the same thing? This would allow the water flow to be cut off quickly and easily from inside the boat.

Such valves are available inexpensively from just about any Home Depot or Lowe's in the plumbing section. You should be able to find one and barbs to match your tubing. Here's a link to what I'm talking about at Home Depot:

https://www.homedepot.com/webapp/wcs/stores/servlet/Search?keyword=pvc+ball+valve&langId=-1&storeId=10051&catalogId=10053

Some barb links to adapt the valve to your tubing:

https://www.homedepot.com/h_d1/N-5yc1vZ1xg1/R-100210038/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

https://www.homedepot.com/h_d1/N-5yc1vZ1xg1/R-100210038/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

Just a thought.

Dave

Thanks.

I hadn't thought of the ball valve, but in this application, it probably isn't going to work from an access standpoint. What I'm doing is installing a large cooler livewell (96 quart or so) in a 1648 I'm working on. The tank is going to be permanently mounted, and the customer wants a drain plumbed to the outside of the boat, hence the need to plug the fitting. As the cooler is nearly as wide as the hull, I don't have enough room for the ball valve in between the fittings, and even if I did, access to it would be through a storage hatch, where it wouldn't be easily reached. The plug (from the inside of the well), is probably the best bet here.

It looks like the 1 1/8" fitting should do fine. The 15/16" hole should work with a standard 1" drain plug (they start out at 7/8, so it wouldn't have to expand quite as far as it would in a 1" boat drain).

Thanks for the help,

Dawson

bassboy1 said:

It looks like the 1 1/8" fitting should do fine. The 15/16" hole should work with a standard 1" drain plug (they start out at 7/8, so it wouldn't have to expand quite as far as it would in a 1" boat drain).

Click to expand...

Nope. 1 1/8 ID vinyl tubing is not easily available, and I'd rather not use the corrugated bilge pump hose that does come in 1 1/8. Looks like I'll be jumping back to 3/4 inch, and using an 11/16 plug, which of course, I'm going to have to order separately, as no one that I usually deal with sells plugs of that size. :roll:

Some live well drain plugs. Looks like the third one might be the best option from the reviews:

https://www.basspro.com/webapp/wcs/stores/servlet/Product_10151_-1_10001_10211469_225003005_225000000_225003000?channel=froogle&mr:trackingCode=AECF75AE-03A7-DF11-904F-002219319097&mr:referralID=NA

https://www.basspro.com/webapp/wcs/stores/servlet/Product_10151_-1_10001_8987_225003005_225000000_225003000?cmCat=CROSSSELL_PRODUCT

https://www.basspro.com/webapp/wcs/stores/servlet/Product_10151_-1_10001_22982_225003005_225000000_225003000?cmCat=CROSSSELL_PRODUCT

This outfit lists several sizes.

https://www.go2marine.com/product.do?no=35502F&WT.mc_id=gb1

Don't feel bad about not finding the part from your standard supplier. I've had that happen to me multiple times in the gunsmithing business. One guy will have 14 parts for a gun you're repairing, but will be missing one part. Another supplier will have the 15th part, but won't have the 7th and 8th parts on my list. It's just one of life's little challenges. ](*,)

Something I started doing with parts I find myself needing on a fairly frequent basis was when I ordered something like the plug, I'd order two and have it shipped United States Postal Service. A little bit slower sometimes (but not always), but it got here. I keep such items labeled in a box of plastic bins I bought at Home Depot.

If I were doing boats, I'd keep a small stock of thru-hull fittings and such as well as buying tubing in bulk boxes like the Marine outfits and car mechanics do. Makes things much handier over the long run to have a box of tubing and a bin full of common size fittings right there when you need it. Also makes it less painful to order the oddball item from a non-standard supplier.

double post due to net lag

DaveInGA said:

Don't feel bad about not finding the part from your standard supplier. I've had that happen to me multiple times in the gunsmithing business. One guy will have 14 parts for a gun you're repairing, but will be missing one part. Another supplier will have the 15th part, but won't have the 7th and 8th parts on my list.

Click to expand...

Not a big deal, except for the fact that I'm needing a plug that costs 2.30, and shipping is going to be twice that. :roll:

bassboy1 said:

Not a big deal, except for the fact that I'm needing a plug that costs 2.30, and shipping is going to be twice that. :roll:

Click to expand...

If you can, buy some other stuff you need to put with it. That's what I do and I'll buy an extra one or two. Unfortunately, no other way around it.

Dawson,

Go to https://www.flow-rite.com/marine and do it right... I'm pretty sure Jeff won't mind paying a little extra for something like this..

Is he still using that big white cooler? If so, that's a 120qt cooler...

by the way... I think I've got some of the good hose that I used left over. I'm pretty sure it's 3/4" ID. It was the most expensive line you could get at Home Depot. If I've still got some left over, I'll look tonight and let you know... If I do, you can have it.

He brought me a green cooler. I believe it is the same size as his white one. A buddy of his gave it to him, which allowed me to have one to install in the boat, and him to still have the white one to finish out this season with.

He brought me an aerator kit from BPS (from what I was told, I'm led to believe it is the same as what is in his white cooler), and instructed me to wire it into a switch, install a drain right to the side of the boat, and then supply a 12v. plug for him to plug a portable fill pump (one that is thrown over the side). I'll figure up what would be needed to set that up, and call him this afternoon, and see what he says. It will be tight quarters to fit that stuff in, as the supplied cooler is as deep as the boat deck, leaving us no room below it, and it takes up most of the width of the boat, leaving very little room beside it.

Russ,

I just talked with him, and he would rather just stick with the method we planned, with the plug and separate fill.