Plugging thru hulls from the bottom

[Skipper]

I previously posted a topic similar to this asking how to do it, as I had to service overdue and sticking seacocks.
Some said wood plugs, plus other remedies. Most said not worth it, they leak.
I thought and thought about this but could find no resolution.
So I scheduled a haul out for this coming weekend. $300 round trip on the lift, plus $100 yard time. $400+.
Then, as the eyes find what the mind needs, I'm walking through Ralph's grocery last week, and just happen to glimpse a rubber tub stopper in the kitchen isle. -pics
Wow. That looks like it would work. Rubber stopper with a flange. And a pull ring. And the right size.
I buy one, and then hustle over to West Marine to stuff it into a 1 1/2" bronze thru hull. It fits perfectly snug, and bottoms on the flange.
OMG it's a fekkin' thru hull plug!

So I went back to Ralph's and bought enough to plug them all.

Just finished servicing my seacocks.
Material cost = $12
Diver to install plugs - $20
Total cost = $32

Didn't leak a drop.

 

[Benny17441]

I like the pull rings as you can tie a fishing line to them and run the lines to the rail or stanchions and pull them off when you are done.

 

[Skipper]

I like the pull rings as you can tie a fishing line to them and run the lines to the rail or stanchions and pull them off when you are done.

And I thought I was smart.
That's brilliant.

 

[agprice22]

Unspeakable parts of my body clench and shrivel thinking of opening or removing seacocks for replacement while in the water!
I am glad this worked out well! I could imagine a dozen ways this could go wrong!
-Andrew

 

[Capt jgw]

If you have a wood plug handy to drive into the through hull if the rubber plug came off, this is not unreasonably dangerous. I've heard of guys installing transducers with a diver holding a bucket under the hole. Now that's scary!

 

[seadaddler]

Great idea for sure,I had a stuck transducer and when my diver came to do a cleaning
he said no problem and used a red plunger with out the long handle but I like your idea.
one or two of my thru hulls is getting very hard to open and close and maybe use your idea to add some lube.
Thank You and great idea.
Nick

 

[Skipper]

I service one at a time. They're tapered cone seacocks. The cone barrel slides out the side of the seacock body. If the the plug springs, I could just slide the cone back in.
However, the plugs are a tight fit, and the rubber is stiff enough. Like a tub stopper. I have 7 thru hulls and none had a leak.

 

[Skipper]

I like the pull rings as you can tie a fishing line to them and run the lines to the rail or stanchions and pull them off when you are done.

Ok I tried this today. Had to redo a weeping seacock. So tied a cord to the ring and plugged the thru hull. Luckily this one was close to the waterline so was able to do it from the dock. Just retie the boat to put the thru hull close to the dock finger, then get on my back and reach up under. We have floating docks so the boat is always next to the fingers in height.
Anyway when I went to pull the plug, it just pulled the ring out of the plug. The plug is in there quite snug. So had to get my arm back in the water up to my shoulder and pull out the plug from the edges of its flange.
Was a great idea but the physics prevent it working.

 

[agprice22]

it seems it worked TOO well. That is a good thing! I would guess hydraulic pressure pushed the plug in tight when you unscrewed the thru-hull. That is what you wanted to a lesser extent.
Sounds good. I will store this for future use. In the meantime, I will be marketing my new "watertight thru-hull maintenance plugs... replace or maintain your thru-hulls right at the dock!"... at 10x the price, of course!

 

[Skipper]

it seems it worked TOO well. That is a good thing! I would guess hydraulic pressure pushed the plug in tight when you unscrewed the thru-hull. That is what you wanted to a lesser extent.
Sounds good. I will store this for future use. In the meantime, I will be marketing my new "watertight thru-hull maintenance plugs... replace or maintain your thru-hulls right at the dock!"... at 10x the price, of course!

I've already bought the patent.
BTW I was referring only to the pull line idea not working. The plugs are fabulous.