Aluminum Hull Issues

YachtForums · 11-29-2004, 07:38 AM

Aluminum Hull Issues Thread...

alloyed2sea · 11-29-2004, 02:53 PM

Yup, itz one of the best materials to make a boat hull out of.
But Roamer boat owners already know that.
"X" makes the spot guys - you've arrived!

YachtForums · 01-30-2005, 02:22 PM

There was a thread several months ago on the issue of "aluminum hull blisters". It was popular topic with a few revelations. Thought you might find it an interesting read. Here's the link...

http://www.yachtforums.com/forums/showthread.php?t=599

toppot · 03-16-2006, 03:51 PM

Meta is building endurable aluminium hulls for both sailing vessel
and motor yachts.

any body heard of the building of ANABASIA ?and where she is floating?
She shall be 14,5 m trawler high-speed luxus
by constuctors Mr Joubert and Mr Nivelt(France)

Apreciate any hint.

Cliff Schultz · 04-20-2006, 09:49 AM

I am considering buying a 37' Alum Express. I have a galvanized steel dock in a fresh water lake (Lake of the Ozarks, MO).

My concern is a galvanic response with the boat hull being the softer of the two and ending up with a major problem.

I have been a boat owner for 40 years, last boat was a 40' Pacemaker SF and always admired the Romers when living on inland waterways but do not want to damage a boat out of lack of knowledge about this issue.

Any advise would be greatly appreciated. I have read some of the comments on the various threads but remain confused and concerned.

Ken Bracewell · 04-20-2006, 10:56 AM

A good place to start would be to be certain that you have galvanic isolators on your shore power lines.
Another good tool is something called a Capac monitor. It is a simple meter which takes a reading through a silver-silver-chloride sensor which is mounted on the hull. With it you are able to look at any galvanic activity at the push of a button. I don't have a current price, but remember them as being very affordable.
If there is still a problem with the installation of these two items, you would next look into a problem with stray current on your dock.
Enjoy your new boat!

JimBauer · 04-21-2006, 01:38 AM

Cliff,

I think this is going to be an answer that should start some discussion. I don't think it's going to matter if you use fenders and lines and don't bond your boat to the dock. If you are in FRESH water, there is very little conductivity in the water, it makes a very good insulator. Use the two leads from your ohm meter and check the resistance between your boat and the dock, probably a couple of megs... If you don't have an isolation transformer, make sure you use a good galvanic isolater on your shorepower and make sure that it is UL approved. Mercury Outboard makes one of the best under their Quicksilver label.

Jim Bauer
San Ramon, CA
73 55 Roamer

alloyed2sea · 04-25-2006, 01:40 PM

..., should answer this and alot of other similar type questions that you may have. Check it out here:
http://www.geocities.com/alloyed2sea...icalForum.html

Roamer46inFl · 05-22-2006, 05:24 PM

The prior owner of our aluminum Roamer Riviera 46 took the fuses out of the capac unit because he was afraid of electricity and water. He also applied the bottom paint layers incorrectly. Upon having the bottom soda blasted, we discovered a small hole in the hull near the connection for the capac monitor. We are in SW Florida. Is there anyone near here who can check the capac unit to see if it is operational and to instruct us on its proper use. Also, we would like to have the entire boat painted. We are wondering if anyone has any recommendations on where to have this done. We have to move the boat out of Florida by July so we would consider locations up the east coast or across the gulf. Thanks for any input.

Michael

alloyed2sea · 05-23-2006, 11:23 AM

Short answer - shut her down, and spend the dough on defensive measures.
Refitting and recalibrating a CAPAC unit cant be easy, and thatz what it needs 25+ yrs later. Better to strip, allodine, zinc chromate and epoxy (Interlux 2000/2001E) the bottom than that.
Cold tar is also a good "protectant".
Mind you, aluminum does just fine by itself in salt water - itz just all the stray galvanic currents (properly wired onboard?), dissimilar metals (got nibral props?), and poor marina electric connections (what, you got a slip in Southern Florida?!!) that can lead to trouble.

Click on the Technical FOrum for more detailed info - and good luck!
Cheers,
Eric
"Tin Tonic"
PS - Got a hull#??

JimBauer · 05-31-2006, 12:11 AM

As always, I'm a little slow on answers on this forum, but I have to disagree with Eric on this one. First question: are you in salt or fresh, if fresh take Eric's advice as your Capac system isn't going to work properly. If salt, first check that your Capac meter is working properly, is it reading in the protection zone for aluminum. If it isn't reading at all, take a sensitive multimeter and read directly off of the hull and the sensor. If it's reading note the reading and post it here. Next put the fuses back in your unit and wait about 24 hours and recheck the readings, mine sets right about .975 which does an excellent job of protection. If it's high or low, you'll need to have it repaired and/or adjusted. If you've got the schematic afrom the owner's manual you can have it repaired by any good electronics shop or a good amatuer radio ham. If not contact me via the Yahoo group as I check it more often and I'll be happy to e-mail you a schematic.

Jim Bauer

jbreske · 08-17-2006, 08:06 PM

I am trying to sell my 41' Roamer Regal 1969 and I just had the bottom painted. Hopefully the right way, it looks great. We are putting zinc plates on the keel, rudders & shafts. Does anyone know if the keel must be free from any bottom paint, were the plates will be attached for this to work correctly.
It's in fresh water.

alloyed2sea · 08-18-2006, 07:49 AM

Quote:

Originally Posted by jbreske

I am trying to sell my 41' Roamer Regal 1969 and I just had the bottom painted. Hopefully the right way, it looks great. We are putting zinc plates on the keel, rudders & shafts. Does anyone know if the keel must be free from any bottom paint, were the plates will be attached for this to work correctly. It's in fresh water.

Zinc plates on the keel are a great idea, and are not required to touch bare metal to work. Bolted two Sealloy (low grade aluminum) "strips" (purchased from Marinette Yachts) onto the keel in the rear of my Roamer (AL), near those ionically demanding props and shafts, and they have served me great for over four years. Later, when some "popcorning" appeared up front, I added a strip there and stopped that problem (whatever it was).
So do proceed - and good luck with the sale.
Cheers!
Eric
PS - You can always call Jim Wick at www.chrisparts.com -- he will know alot (alot) more.

timbo · 10-05-2006, 09:57 AM

Hi,

I found an alluminium racing Frers 45 but it is quite old and by the looks of it it has not been maintained very well over the years. can you advise me a way or a specialist company that would be able to conduct a survey into what is the state of the hull?

waiting for ideas,
tim

JimBauer · 10-05-2006, 12:27 PM

Timbo,

Check for a tank inspecting company using ultrasound metal thickness gages. You'll need to have a drawing of the hull divided into 1 foot grid squares and also mark the hull off in 1 foot sqares. You'll need to record each reading and hope that each reading is representative of the remaining plate. Been there, done that, and it ain't cheap......

Jim Bauer
San Ramon, CA
1972 55 Roamer