what is this on my hull?

[Razgo-]

When i first saw this i thought it was just the antifoul peeling back. but after some new paint had been applied and i saw it again i grabbed it and it was a piece of metal. Haven't had a chance to get inside the boat to see any evidence from up top yet.

anyone know?

[chop69]

secret winged keel?? i have no idea but hopefully someone on here can enlighten us?

[Shanoss]

Klingon.... No doubt

[Vindicator]

Thats one of those endangered alloy barnacles. Buggers of things to get off!

Cheers
Kezza

[tigermullet]

A thin metal patch?

[Razgo-]

hmmmm..... i thought a patch maybe also but still seems weird even for that. i didn't pull on it too hard but it felt like solid metal. I know there is a lot of copper sheeting on the hull but not sure if that has anything to do with it either.

[TheRealAndy]

Its not an old pitot tube speedo or some type of transducer??? Looks like it is there on purpose. Odd though.

[ronnien]

looks like the same colour as the hull, thats telling me it was there before the hull was painted?

ron.

[Razgo-]

they painter painted it the same colour. it was blue before when there was blue paint. I never thought of the transducer so perhaps that's it. I will check it from the inside once it gets in the water hoping tomorrow.

[gofishin]

Old timber displacement boats used to be sheathed in copper sheeting below the waterline, which from memory was both a good antifouling and prevented borers getting into the hull. Maybe some 'old salts' can confirm or enlighten us?
cheers

[foxx510]

Wild guess, but I wonder if it was for "grounding" electronics to the water, ie a radio or something, and was originally bare brass or something. Probably not.

[Razgo-]

yes the copper sheeting does indeed prevent marine growth on the hull. The previous owner said he gets 2 years out of antifouling and even then its very little stuff on the hull after 2 years.

I thought of grounding too but wasn't sure you actually ground electric current in water like that?

[tunaticer]

Is it a sacrificial anode piece of sheet zinc?

Jack.

[rat_catcher]

I thought of grounding too but wasn't sure you actually ground electric current in water like that?HF radios require a grounding plate, but it is generally more like a square piece of solid metal flush with the bottom. This looks more like a piece of copper sheathing to me.

[tigermullet]

Because the hull has been copper sheathed then it is probably just a section (or a patch) that has let go. Shouldn't be a problem - I hope not.

[tigermullet]

It's a shame that you cannot get a look inside the hull before getting back into the water. From the photographs I can see why. No sense risking the boat coming off the supports.

A closer inspection and maybe even a gentle probing might reveal that it will be quite okay to bung it back in place with a few copper tacks (nails, whatever) and anti-foul over.

Of course it is difficult to tell from a photograph but if my assumption is anywhere near correct you should not have too much of a problem with just putting it back and repainting.

[bigjimg]

If your hull has been copper sheathed it probably is just a copper patch where the sheathing had a small hole.We would put these small patches on the keel before a new chafing batten was installed on the city ferry fleet.Jim

[Roughasguts]

Was the engines original cooling system a copper pipe running down the keel. ?

If it did have that type of cooling that could be one of the original saddles to secure the pipe.

[rat_catcher]

Was the engines original cooling system a copper pipe running down the keel. ?

If it did have that type of cooling that could be one of the original saddles to secure the pipe.
Yeah that is called 'keel cooling' and is a good possibility too, although there should then be more than one of these along the hull bottom. See if you can scrape some paint off it back to bare metal and that should tell you if it is copper or something else.

[Razgo-]

I can safely say it is definitely not copper. It is hard metal and i could not bend it.

not sure about any cooling system like that. as far as i know it did have a v8 at the stern. currently has a 6 cyl at the stern and is a v drive system.

I will ring the workshop this morning and see if one of the mechanics can get inside to have a peek.

[FNQCairns]

Used for fish/contraband smuggling in the past??

cheers fnq

[Razgo-]

well that's a thought too lol, the boat is called rum runner.

[FNQCairns]

Yes mate it's in exactly the right spot forward.

cheers fnq

[Razgo-]

well i thnk the verdict is in even though i thought it wasn't copper.

I spoke to George from onshore marine and he said yes it is more than likely a copper keel cooling system pipe. He said this because he had the copper pipes on his 36' chris craft timber boat still attached.

So it may be indeed where they cut the pipe away from the hull.

Thanks all for your input as i would never have figured out what it was.

thanks

[FNQCairns]

So how do those pipes work if anyone knows, do they exit and re-enter the hull proper?

All in all a very unexciting conclusion..:)

cheers fnq

[cormorant]

So how do those pipes work if anyone knows, do they exit and re-enter the hull proper?

All in all a very unexciting conclusion..:)

cheers fnq

Yep that's right and they are good in many aspects as there is no water intake to get clogged and you can run coolant. Just works like a heat exchanger. Works fine on older motors that don't generate a lot of heat quickly and have headertanks etc . Can get damaged but they are pretty thick pipe and protected by being close to keel. The 2 through hull areas are the only issue as you have a expanding and contracting pipe and they can leak if motor has overheated or calking not done properly

[Razgo-]

found an interesting conversation on this here http://www.woodenboat.com/forum//showthread.php?t=53239

and pic here of the pipe http://www.ronlloyd.com/oddstuff/sling.jpg

more specs here http://www.seafrost.com/keel%20cooler.htm

Advantage of forced air-cooling with the addition of pumped water-cooling. All of the above plus:

* Water and refrigerant flow in opposite directions (counter flow design) through the condenser to cool refrigerant to water temperature.
* Flow of pumped water scrubs water and heat away for excellent thermal transfer.
* Maximum capacity can be extracted from the compressor.



Disadvantages of the keel cooler:

* Less energy efficient, poor heat rejection, runs hotter than fan cooling.
* Runs extremely hot when boat is at rest in still water and hotter still at rest and fouled with marine growth.
* Does not have a fan to cool electronics and compressor for recommended high output compressor use.
* Requires large hole in the hull.
* Creates drag. Reducing boat speed.
* May require zinc maintenance.
* Requires diving for cleaning. (anti-fouling)
* Potential electrolysis problem.
* Keel cooler must be remotely located under floorboards etc.
* Extra refrigerant connections in damp area below the water line are subject to corrosion.
* Extra tubing runs from the compressor to the keel cooler and back to refrigerated space.
* Cannot be operated on the hard. (Boat on land.)
* Requires haul out for replacement.