Marlin 300 Drain Plug (aft bilge)

A

Antigua Larry

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I picked up my Marlin 300 from summer storage today. It ran great back to our home lift, but while preparing to dock, the aft bilge pump started running - repeatedly, and a lot. After I got the boat on the lift, I observed that someone was good enough to remove the drain plug while it was in storage. Unfortunately, I didn't check it before the boat was launched. I believe that the plug is a 1/2 inch brass plug. like this:

Screenshot 2025-10-30 123732.png

Can anyone confirm that this is the right plug? It's not available in Antigua, and I'd like to order it just once.
 
Last edited:
looks correct.
Usually when the marina or yard removes a bilge plug, they put it where you can find it. The more common place is a cup holder near the helm.
 
Yes - available pretty much everywhere. Bronze is better, FYI.

Edit: Just saw you mentioned it's not available in Antigua? I never would have guessed that something so commonly used is not available. So you have pretty much the only boat there without a garboard drain?

You can use a plain steel one from a hardware/plumbing store for short periods of time - especially since you're not keeping the boat in the water.
 
It's not anywhere in the boat, and I didn't have any work done during the summer. My guess is that it was taken by someone who thought it was a good joke. Security is pretty minimal, even though it is an indoor storage area.

The only close thing I could find locally is this one, which requires a plate for the plug to screw into. We do have a number of hardware stores here, so I will try that out while I wait for these to arrive. It;s a pain, because these are cheap - $9 for the pair, but I have to get them here. I have a freight forwarder in Miami. It won't be expensive for air freight, but one never knows when they will ship. It could be several weeks sometimes.

Here is what I found at not-Budget Marine:

Screenshot 2025-10-30 153000.png
 
There are expanding rubber plugs with a tightening bolt or lever. You might find one of those locally
Are hardware fittings metric in your country. If so, that is probably why you don't see a 1/2 in NPT
 
seasick said:
There are expanding rubber plugs with a tightening bolt or lever. You might find one of those locally
Are hardware fittings metric in your country. If so, that is probably why you don't see a 1/2 in NPT
Click to expand...
They carry both English and metric here. The problem is that the only screw-in fitting was the one that requires the plate, as I showed in the second image. I have a couple of more chandleries to check today. I have ordered the ones that posters here confirmed are correct, but hopefully I can find a local source. For the tons of boats in Antigua, we don't have much of a selection of parts - St. Maarten is much better.
 
Larry, that plate that you showed is already on your boat. The plate on your boat should match up the plug you found. Both of those things are standardized.

And... are there other boaters nearby? Many boaters carry an extra garboard drain plug on board - you could ask them to borrow one. Or a marina near you? They will definitely have those laying around.
 
One of the laws of boating is that if you have one bilge pug, eventually you will misplace it. If however, you have two you will never lose either:)
 
The saga continues: I found what I am pretty sure is the correct Garboard plug at a chandlery today. Now the bad news - I already dropped it into the water. My plan was to get in the water behind the boat, lower it until the hole was just above the water, and then have my wife pass me the plug, contained in a drawstring net bag. Unfortunately, I had a Wile E. Coyote moment, as I forgot the bag would close up by the drawstring. While at the swim ladder, opening the bag to get to it, i missed the grip and it made the 8 ft. journey to the bottom.

I was able to get another - plus an extra this time. My new plan is to use a float under the boat, so if I drop it there will be something to catch it. I'll also use a small wet rag to grip it with, better than my salty fingers. It is not easy to install this from the water.
 
And Seasick's prophecy holds true!

8'? Take a big breath!

:) :) :)

I once saw a picture somewhere of someone tying an opened umbrella upside down to their engine while working on things....
 
Currious,,, What is in the hole now? If no plug, the boat should be sinking:)
What makes it hard is that your body wants to float but the hole is below the water surface. Iy you wear a PFD, inserting the plug will be very tricky. In addition, your body tends to push away from the transom as you push on the plug. If you can get something behind you to keep you from pushing away, that will help.
It is possible that the inside threads of the flange are gummed up making it hard to start the plug. It is hard to clean the hole while in the water.
In any case, wrap a couple of turns of teflon tape on the new plug's threads. Two turns is enough. It will make threading in the plug easier It will also make it a lot easier to remove it if needed.
 
seasick said:
Currious,,, What is in the hole now? If no plug, the boat should be sinking:)
What makes it hard is that your body wants to float but the hole is below the water surface. Iy you wear a PFD, inserting the plug will be very tricky. In addition, your body tends to push away from the transom as you push on the plug. If you can get something behind you to keep you from pushing away, that will help.
It is possible that the inside threads of the flange are gummed up making it hard to start the plug. It is hard to clean the hole while in the water.
In any case, wrap a couple of turns of teflon tape on the new plug's threads. Two turns is enough. It will make threading in the plug easier It will also make it a lot easier to remove it if needed.
Click to expand...
The boat is on a lift
 
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