CONTINUOUSWAVE

On my 1995 Outrage 24 the direct replacement for the transom drain tube at the bottom of the transom is [a plastic tube assembly as ]show at:

https://www.nausetmarine.com/shop/1042050-thru-hull/

The hole diameter of 1-1/2-inch limits what can be used. I thought originally I could use a brass tube as used in a classic. But the [brass drain tubes are only] 1-inch.

Q1: Is there a better alternative than gluing-in this plastic tube?

Q2: What is an alternative drain tube [to the one shown when following the hyperlink mentioned above]?

Archie

If you wanted to use a brass tube, just buy a brass tube with 1-1/2-inch OD. The brass tubes used in making the through-hull drains in classic Boston Whaler boats used a different diameter brass tubing to fabricate the drain, but I do not see why you must be limited to that size. If you want to install a brass through-hull drain similar to the classic Boston Whaler boat drains into an existing hole that was 1-1/2-inch ID, just buy 1-1/2-inch OD brass and appropriate O-rings, and install a brass drain using the same method as used in installing the 1-inch ID drains in the classic boats.

Archie--you can also investigate bronze through-hull fittings. Note there may be conflicts with the transom angles preventing a metal through-hull fitting from siting flush with the surface. Regardless of which material you select, I would seal the drain holes with epoxy to prevent any errant moisture from entering the transom.

Try this this URL:

https://shop.hamiltonmarine.com/inet/storefront/store.php?mode=searchstore&search%5Badvanced%5D=yes&search%5Bsearchfor%5D=thru+hull&search%5Bitem%5D=&search%5Bdepartment%5D=&search%5Bmfg%5D=&search%5Bmfg_part%5D=&search%5Bupc%5D=&search%5Bcode_match_method%5D=E

ARCHIE--if you develop a better alternative to the OEM plastic through hull drain, and that drain is a metal drain, you will likely need to create a bonding system in your boat in order to connect the new metal through-hull drain to the rest of the metallic components that are immersed in seawater. If you install a metal through-hull fitting and it is completely isolated electrically from the rest of the metal components in the boat, you can create a situation where electrolysis will occur.

Avoiding electrolysis was probably one of the reasons that Boston Whaler used a plastic through-hull fitting in the original construction of the boat.

Phil and Jim Thanks for the response. I think I might be able to get a bronze through-hull to work. It look like I have enough clearance on the nut in the bilge where the hole is. I am not really finding a vendor for a 1-1/2 aluminum tube, not a flare tool for that either. I really would like the replacement to be mechanically held together, not just glued together. If the OEM replacement screwed together that would be better.

Ideally I would like to be able to put a Garboard style drain back in there. On my boat it looks like the original plastic through hull failed and was replaced with a plastic Garboard drain, which only sealed a part of the wood in the transom hole. What was pulled out looked like a Moeller Boat Transom Drain Tube with Pipe Plug

The replacement drain exposed the wood on the transom. The transom is about 3- to 4-inches thick where the hole is. The hole also looks to be 1-1/2-inch round.

Luckily the wood is not bad there, meaning when I pulled everything out there was no water coming from the wood. The wood is still solid. So I cleaned it up, and it is now ready for a proper sealed drain to be installed.

Q1: Does anyone make a through hull that has a internal threaded for a plug?

Q2. Can I place a West Marine garboard drainover a through hull?

Q3. Does anyone make a garboard drain that is completely a through-hull, too. It seemed that all garboard drains look like a like cap that is supposed to seal around the outside of the through hull that is already there.

Q4. If I use a bronze through hull how do I attach a wire to it for bonding.

Thanks
Archie

Acassidy wrote:Q4. If I use a bronze through hull how do I attach a wire to it for bonding.

Typically on a metal through hull there will be a large nut that threads onto the portion of the fitting that extends through the hull. The nut will be on the interior side of the hull.

One means of attaching a conductor to the metal through-hull fitting might be:

• ]Drill and tap a small hole in the nut for a 6-32 machine screw
• Connect the bonding conductor under a machine screw using a ring terminal fitting

Some fittings may already provide for a point of attachment for a bonding wire conductor, for example in fittings made by GROCO which provide a hex fastener for attachment of the bonding wire.

Since you have an outboard engine, you will have aluminum metal of the engine in the seawater. If you add a bronze through-hull fitting, you will have two dissimilar metals in the water. This creates the possibility of galvanic corrosion. The best way to minimize galvanic corrosion is to bond all of those metals that are submerged in the water together so they tend to remain at the same electrical potential. Bronze is more noble than aluminum, so it would tend to erode the aluminum. More at

Marine Corrosion 101
https://www.boatus.com/seaworthy/magazi ... on-101.asp