replacing through hulls in water

[Dockhead]

Originally Posted by captstu

I installed a depth sender in the water - not a terribly difficult job. Took a coffee can in the water (with SCBA), and had a buddy drill a hole from the inside to the outside. Once the point went through the hull, I placed the coffee can - with the transducer and cable inside - and the sealant pre-applied to the threads - over the hole.

Buddy drilled the hole, took out the bung, grabbed the cable and wiggled the transducer into the hole.

Once he had the transducer, he tapped twice, I removed the can and held the transducer while he screwed in the retainer ring and tightened it.

Done.

the water was very cold, I developed a dreadful cold that cost far more than lifting the boat out.

Possible, but now I just ground the boat at high tide, do my thing at low tide, and wait for the next high tide to float off. No problem, no fuss, and no cost.

Very cool operation!


FWIW, I have dried out my bulb keel 25 ton 54-footer to scrub the bottom and service the prop and anodes. It worked fine, although I'm not sure the nerves were worth the 150 pounds (these days less than $200) I saved on a haulout.

Obviously you need to be in an area with sufficient tidal range, to do this.

[Tkeeth]

Originally Posted by battendown

Not the handle, the whole fitting...

Through hull, haul it. If it's just the seacock I did it after I broke one and didn't have the ability to haul it. It really isn't that bad, just leave the valve open when stabbing it and screwing it on.

[fstbttms]

Originally Posted by zeehag

in san diego a haul and launch is over 1800 usd for a 35 ft boat.

1800 bucks for a haul, block and launch?

The going rate for that in San Diego is around $14/foot. That's about $500 for your 35-footer. A couple hundred more to have the yard install the thru-hull and it still comes out cheaper than what you claim you paid a diver to do. Bwahahahahaha!

[jheldatksuedu]

I've been able to do it using a 5 gal bucket and a foam gasket to seal the top of the bucket against the outside of the hull. This gasket will depend on the amount of curvature at the point of the hull you are working. I learned the hard way that you have to build a cross brace inside the middle of the bucket to keep it from collapsing. A wooden cross brace out of 1x2's half way down the bucket works fine. Just a couple feet of water pressure is enough to crush a standard 5 gal bucket. You should also have a really good bilge pump set up to take care of a problem when you learn something like this, and a piece of something like a rubber mud flap that you can slap over the outside of the hole to seal it when something like this happens and you remove the bucket for plan B. You need to think through the problem on how you will grab and pull the new part into position that you put in the bucket before you put it in place on the outside of the thru hull. You will also have to hold the bucket in place until you can let let the water out of the inside of the bucket and let the pressure grab it and hold it. It will hold it real well, even just a foot or two below the surface. Probably a rope through the new part and a way to grab the rope through the hole from the inside to pull the new part into position.

A wet/dry vacuum with long skinny tube is also a good thing to empty all the water out of the bucket after is is sealed against the hull and the thru hull or sensor is removed. I have a 5 gal bucket that I built a special lid with two vacuum hose connections that allows me to use the dry vac as a wet vac without removing the filter. It allows easy emptying 5 gals at a time when you need to dry the bilge completely. A 6 foot 1 inch pvc tube makes a great vacuum wand to get to the bottom of my bilge.

I do all my work by myself, so I try to figure a method that allows me to stop halfway done and consider plan B. Even if you do have a plan blow up and a removed thru hull is flowing full flow, as long as you are prepared and don't go too crazy you can deal with the leak and flood and keep the boat from sinking.

You might consider if the thru hull is in such a place that you can heal the boat over and not have it under water at all. I had to get my 54 foot mast under a 49 foot bridge, I was able to heal the boat over with a bunch of full plastic water tanks on one side deck.

[Pete7]

We (the diving club) replaced a lowrance transducer in a 80T Admiralty Fleet Tender belonging to the Queen at the time, using the same technique as Capstu mentioned with the jam jar.

Take one plastic bucket with foam pipe insulation around the lip. Put transducer in bucket or in this case through hull with wire and loop through the middle of the bucket. Diver puts bucket over hole and holds it there. Crew on the inside push through hull into bucket and fish the new one with a coat hanger in the wire. A squirt of sealant and screw the through up up tight.

The actual job took about 10 minutes, the briefing so everyone knew what was expected of them somewhat longer but all went well and we didn't need the nearby beach and a falling tide.

Pete

[nautitrix]

My two cents
You are using the wrong sea-cocks and thru-hulls to start with. go to an outdoor store and get a couple of boxes of poo-powder. Get some bio-degradable bags at publix that will fit inside your head and fold down the sides for about 4 inches. get a funnel and an empty windshield-washer fluid bottle. Tighten whatever flange is on the inside of the thru-hull, place the plastic bag in the head and keep the poo-powder by the head when you do #1 use the funnel and plastic bottle. When doing #2 use the head and cover the waste in poo-powder. If it gets smelly, tie the bag and throw it in the trash. Just like junior and senior diapers. Dump the bottle over the side or in an outhouse. Seven days will teach you how much of waste is water. Save the money on the poor fix, get to where you are refitting and ensure you replace all below waterline through hulls with 3 bolt thru-hulls and proper sea-cocks. Look into the proper process and type of thru-hull fittings and you will be much safer after the refit and sleep with confidence. Put in a bilge pump alarm!!
Do not waste any more money until you can do all your thru-hulls properly!!!!

[Kudawudashuda]

If an outlet then consider replacing above the waterline. The less chance of ingress the better. Also, you can often find a yard that will lift a boat for a few hours at a much reduced rate.

[darylat8750]

In an emergency you do what you have to. It would be very hard to do this properly in the water and Murphy is always standing by.

Originally Posted by battendown

Looks like a composting toilet for me until i haul out.

That's what I would do. It'll be out of the water soon so just wait and do it right.
Collin (MaineSail) knows whereof he speaks.
Replacing Thru-Hulls and Seacocks Photo Gallery by Compass Marine How To at pbase.com

[HopCar]

I see Paul Kelly beat me to it but here is another video of the Seabung.

https://m.youtube.com/watch?v=f-P49Y-o6Y8

My old company sells them in the US. Seabung Breach Control

[Uncle Bob]

Originally Posted by battendown

I've seen videos and talked to a few sailors that have said and explained replacing through hull fittings while in the water. Seems to be quite a few videos of swapping out transducers in water. Of course their is an inherent risk in doing this just want to hear real experiences and thoughts. My seacocks are stuck shut and one can turn pretty easy like.

Hi, are you wanting to change through hull fittings or sea cocks.
I believe that the sea cocks are doable but the through hull fittings would be impossible.
Cheers

[seabreez]

Originally Posted by battendown

I've seen videos and talked to a few sailors that have said and explained replacing through hull fittings while in the water. Seems to be quite a few videos of swapping out transducers in water. Of course their is an inherent risk in doing this just want to hear real experiences and thoughts. My seacocks are stuck shut and one can turn pretty easy like.

If you like living dangerously... then that is your thing... go for it! I like to study anything I take apart to see how it outlived it's life... then I try and see what I can do to make things last as long as or better... I am a specialist at refloating things that go under... your call!

[UNCIVILIZED]

If there's any chance of needing to do an emergency careening, make sure that the beach in question isn't a muddy one come low tide. As the sucktion may hold the boat on her side as the tide comes in.

[capngeo]

I've changed thru-hulls, transducers, prop shafts and rudder shafts while in the water... no big deal with a bit of common sense applied

[Scott Berg]

Terminology issue:

A Thru Hull is a fitting screwed from the outside for the boat into a SeaCock.
A Sea Cockis a valve fitting thru-bolted (I hope) to the hull with a backing plate (usually) that a thru hull screws into. While you can change a ball valve attached to a thru hull while in the water, this sort of work is always always best done when the boat is hauled. This is one of my favorite diagrams of the right way to do this... https://www.jamestowndistributors.co...Large/538a.jpg

[pcmm]

Originally Posted by Dockhead

WARNING: this is NOT based on actual experience. YMMV.

But I don't see why in the world you couldn't change a ball valve (is that what you're talking about?) with the boat in the water.

You need to plug the through hull somehow (diver with plunger, Sea Bung, wooden bung hammered in from underwater, etc.).

THEN, gently work the ball valve on the through hull to see if the through hull is solidly in place. If not, then abort! And haul. If it is, then proceed.

Remove the ball valve and install the new one.

Remove the bung/plug, etc.

Have a beer.

It's easy for others to spend your money -- "don't risk it; haul the boat, etc., etc." If it were me, I would of course try to do it when the boat is out of the water anyway for other purposes. And in fact I have replace a few ball valves over the years, and always found a way to do it with the boat out. But if you can't, then I would seriously look at more adventurous ways to do it rather than spend all that money.


Now if on the other hand you're actually talking about the through hull -- then I agree with all the comments above. You need to SEAL them -- and I don't see how you could do that with the boat in the water.

The only problem with that is you end up with just as unsafe a situation as you had before. a ball valve threaded onto a thruhull IS NOT a seacock. it is inherently unsafe as you're mixing NPT threads with NPS threads ( tapered thread on a straight thread) this means that the integraty of the connection is dependent on 1 maybe 2 threads that make a solid connection. a properly bolted seacock is the only valve to put on. They are not much more expensive than doing it incorrectly. Its very tough to change one of these out while on the water. I wouldn't try it. As we haul every year up here north of the 49th parallel its easier to do. Hauling isn't expensive and its worth the time to do it correctly not replace a bad setup with a bad setup.