Boat plug.

[ash2020]

My (new to me) 77 year old wooden boat has this bronze plug below the waterline. It's fairly important that it doesn't come undone! It looks like it once would have had a wire mousing to the plate it goes into but now there isn't anywhere to wire it to. Any ideas what would be the best approach, cross fingers? PTFE tape? boss white and hemp? Is it even possible that the engine vibrations could loosen it?

 

[Dellquay13]

My immediate two thoughts were;
Replace the boat with something younger than me, it’s far too fraught with potential headaches,
Replace the entire plug with something new that is less fraught with potential headaches. If it’s below the waterline, it wouldn’t spoil the aesthetics?
I guess that if you have just bought a wooden boat, you don’t suffer from such headaches

 

[ash2020]

My immediate two thoughts were;
Replace the boat with something younger than me, it’s far too fraught with potential headaches,
Replace the entire plug with something new that is less fraught with potential headaches. If it’s below the waterline, it wouldn’t spoil the aesthetics?
I guess that if you have just bought a wooden boat, you don’t suffer from such headaches

Yes, good points, well put, but she's a stunner. Even old ladies deserve a chance at a new life! And if it all goes tits up I can always put my snorkel on and undo the plug! And yes, I'm always up for a new challenge.

 

[LiftyK]

This sort of plug used to be, and maybe still is, standard on speed boat transoms. I never had one come loose so you should be quite safe with it. I believe the cord is to put a loop through it to hang it up when not in use.

By all means carry a spare. I can assure you that many a speed boat has been launched with the skipper forgetting to put the bung in. The boat takes a while to sink so you have time to realise the error of you ways or recover if yours inexplicably fell out.

 

[Poignard]

The hole in the plug is not for mousing but is for a piece of cord or light chain to attach it to the boat to prevent its getting mislaid.

There's no reason it should work loose if you tighten it securely but a fibre washer under the head would be a good idea

 

[Poignard]

Pipped at the post by LiftyK.!

 

[ylop]

Does it work (ie seal?). modern plastic ones are not normally moused to stop coming loose spontaneously - but a lanyard on it so you don’t drop in the sea/leave it on the slipway etc is a good idea. You just need a length of line fastened to a small eye/ring.

 

[VicS]

My (new to me) 77 year old wooden boat has this bronze plug below the waterline. It's fairly important that it doesn't come undone! It looks like it once would have had a wire mousing to the plate it goes into but now there isn't anywhere to wire it to. Any ideas what would be the best approach, cross fingers? PTFE tape? boss white and hemp? Is it even possible that the engine vibrations could loosen it?
View attachment 187556

If it is a tapered thread then PTFE tape or Boss white and hemp are the way forward as the seal, must be made on the thread.

If , however, the thread is parallel then the seal should be made with a joint washer under the head :



Replacements available from ASAP supplies

 

[Daydream believer]

The OP's one is identical to the one in the keel of my launch to drain the bilge when it is ashore. It has a leather washer. I have a piece of rectangular steel bar with 2 slots one end & a hole for a 150*8mm bolt the other as a handle. I use this to get it nice & tight as it is awkward to get a spanner on to it when the launch is on the trailer. Using this gadget, I can grip it firmly. I usually add a few turns of PTFE tape for good luck. It is a parallel thread, so that it tightens on to the washer. The leather washer swells slightly when immersed in water which adds to the tightness. The hole in the lug is for a cord to hang it up when not in use. Obviously I remove the cord when it is in place, as it is permanently below water. It is only 3 feet from the engine & has never come loose.
When I first bought the boat, I turned up an Oilon plug as a spare. I felt that Oilon would swell a little & increase water tight integrity. So far I have not had to use it so do not know if it would jam in place

What I did find, was that the plate that the plug screwed in to was not properly fitted & leaked. The solution was to remove it & replace the original screws, with bolts. I rebedded the unit in Sticks Like & tightened it up with penny washers on the inside of the hull.
I would imagine that the OP may have to inspect this part as well,l if the fitting has been in place for some time.

 

[neil_s]

I have one just like it in my dinghy. It has a leather washer, too.

 

[ash2020]

This sort of plug used to be, and maybe still is, standard on speed boat transoms. I never had one come loose so you should be quite safe with it. I believe the cord is to put a loop through it to hang it up when not in use.

By all means carry a spare. I can assure you that many a speed boat has been launched with the skipper forgetting to put the bung in. The boat takes a while to sink so you have time to realise the error of you ways or recover if yours inexplicably fell out.

Thanks. That makes sense. I'm the sort that puts things in a "safe place', only to find them years later.

 

[ash2020]

The hole in the plug is not for mousing but is for a piece of cord or light chain to attach it to the boat to prevent its getting mislaid.

There's no reason it should work loose if you tighten it securely but a fibre washer under the head would be a good idea

Thanks. Yeah, I guess it would have to be a really loose thread to vibrate out.

 

[ash2020]

Does it work (ie seal?). modern plastic ones are not normally moused to stop coming loose spontaneously - but a lanyard on it so you don’t drop in the sea/leave it on the slipway etc is a good idea. You just need a length of line fastened to a small eye/ring.

I don't know yet whether it seals, and no sign of a washer.

 

[ash2020]

If it is a tapered thread then PTFE tape or Boss white and hemp are the way forward as the seal, must be made on the thread.

If , however, the thread is parallel then the seal should be made with a joint washer under the head :

View attachment 187561

Replacements available from ASAP supplies

I don't know whether it's tapered or parallel, I'll measure it next time I'm there. Thanks for the link. I may need to replace it next year.

 

[ash2020]

The OP's one is identical to the one in the keel of my launch to drain the bilge when it is ashore. It has a leather washer. I have a piece of rectangular steel bar with 2 slots one end & a hole for a 150*8mm bolt the other as a handle. I use this to get it nice & tight as it is awkward to get a spanner on to it when the launch is on the trailer. Using this gadget, I can grip it firmly. I usually add a few turns of PTFE tape for good luck. It is a parallel thread, so that it tightens on to the washer. The leather washer swells slightly when immersed in water which adds to the tightness. The hole in the lug is for a cord to hang it up when not in use. Obviously I remove the cord when it is in place, as it is permanently below water. It is only 3 feet from the engine & has never come loose.
When I first bought the boat, I turned up an Oilon plug as a spare. I felt that Oilon would swell a little & increase water tight integrity. So far I have not had to use it so do not know if it would jam in place

What I did find, was that the plate that the plug screwed in to was not properly fitted & leaked. The solution was to remove it & replace the original screws, with bolts. I rebedded the unit in Sticks Like & tightened it up with penny washers on the inside of the hull.
I would imagine that the OP may have to inspect this part as well,l if the fitting has been in place for some time.

Hey, thanks for that. I will check the plate before she's launched. I can easily get to it with an adjustable spanner before launch. I'll do the thread and fit a washer, just to make sure.

 

[Chiara’s slave]

I have one just the same on my 2012 RIB tender. Ours is a parallel thread and has a rubber type washer. I usually forget it on the first launch of the year, the boat has not yet sunk, the immediate starting of the bilge pump gives the game away, and gives my wife an opportunity to laugh at me. Very best of luck with your new (to you) boat. There’s a certain age humans reach which makes them want to own stuff that’s older than they are. Some sort of reassurance that it’s not the end, I guess. Mine is just 72 years old, No bung below the waterline, but plenty else to worry about

 

[Dellquay13]

I have one just the same on my 2012 RIB tender. Ours is a parallel thread and has a rubber type washer. I usually forget it on the first launch of the year, the boat has not yet sunk, the immediate starting of the bilge pump gives the game away, and gives my wife an opportunity to laugh at me. Very best of luck with your new (to you) boat. There’s a certain age humans reach which makes them want to own stuff that’s older than they are. Some sort of reassurance that it’s not the end, I guess. Mine is just 72 years old, No bung below the waterline, but plenty else to worry about

I used to cable tie the drain plug to the top of the steering wheel when winter storing my last motorboat.
It was right in front of me when I came to pre-start the engine at the top of the slip each spring, hard to forget that way.

 

[Chiara’s slave]

I used to cable tie the drain plug to the top of the steering wheel when winter storing my last motorboat.
It was right in front of me when I came to pre-start the engine at the top of the slip each spring, hard to forget that way.

That might be a plan good enough even for me.

 

[Poignard]

Here's a neat solution that requires no string!

£11.41 from Amazon.

 

[Chiara’s slave]

What will my wife find to laugh about me now?

She is sniggering about the thread title. I am pretending to have no idea what she’s laughing about.