Aluminum Chine Extrusions

[afinney]

Hi. I want to build a power catamaran out of aluminum. I've found a design and have been reading aluminum boatbuilding. In the book they show some really cool chine extrusions that would make the whole process much easier. Anybody know where you can get these or is it only for the production boatbuilders?????

Any information would be appreciated.

[FAST FRED]

These are usually NOT extrusions but rolled at a plant to your specs.

YOU specify the chine width & radius , they make it fairly cheap!

FAST FRED

[afinney]

Do you know any plants that do this? Websites? thanks for the information,

[Arrowmarine]

I am not sure of the process fastfred is speaking of, but the slotted chines common to the industry today are definately extruded. (I've seen it made in person. Very cool! Highly recommended.) So are all of the common structual angles and channels that we commonly use. For the unaware, an extrusion is a material that is forced thru a die that is made in a certain desirable shape. (Remember the old playdough factory were you put the clay in the hopper, push down the lever, and and it would come out in a long string in the shape of a star or something? You were extruding" the clay.) In order to do this with aluminum, the material is heated until it is very malable, almost to the melting point, then forced thru a series of dies. A roughing die, which establishes the rough shape, intermmediate die which introduces slots or ridges or whatever, then thru the finish die which gives its final dimensions and smooth finish. There may be several rough, medium, or finish dies in the process depending on complexity. Generally ,the alloy's we use are 6063 t-3 or 6061 t-6. They are broken down into categories: "Open" extrusions are things such as 1x2 channel, 1x1 angle, and the the slotted chines we use. "Closed" extrusions are things like square tube, round corner rectangular tube, or, for example, a 4" pipe with a "Mercedes emblem" webbing running the full length. (picture everytime you cycle the chop saw, a 1/2 inch thick mercedes emblem falls off. Does that make sense?) Some shapes are simple, 1x1 angle for example, and some are very complex, requireing more steps in the proccess and therefore are more costly.

As far as obtaining some, here's how it usually works: You draw up a design for an extrusion, the manufacturer makes the dies and you purchase the dies outright if it is going to be a propriatery item and maybe have it patented, then you buy your extrusion from the factory at a 500 or 1000 lb. minimum puchase. Or: Some companies, like the one we have here, will split the cost of the die if you allow them to sell it to the general public. This usually lowers your minimum purchase weight as well. I am assuming that this is a "one off" project and you are not looking at volume manufacturing so designing a die is probably not the thing for you to do. There are thousands of different type extrusions out there and with a little luck and/or modification, you should be able to find something that will do. As I am not familiar with cat construction, I cant visualize what you would need exactly, but remember this: The slotted chine extrusion was developed for shallow, rocky, whitewater rivers were impact is common. It is very tough and durable, but on the other hand, I've repaired some whitewater jet racers recently that held up pretty well under crash stresses, and they are just .125 to .100 corner to corner welded! If your use is going to be only in open water, the logistics of finding, obtaining, and applying a current chine extrusion that would fit your application may well outweigh the benifits you will gain. You can brace a corner welded joint in a variety of ways that will be just as tough as a solid extrusion. Chine Ext. or not, both ways have merit. Your call.
Now, sources. I remember having a real hard time finding any info on the net about custom extrusions, but you might have more luck. I would contact Pacific Metals in Spokane, Wa. They have a variety of boat specific extrusions. (Incedently, remember what you see in their catalogs, is not all that they have. Be sure to ask. They may have some obsolete stuff laying around that would work perfectly for you. You might also try the "big guys" like Alcoa and Reynolds. Any large aluminum distributor should be able to point you in the right direction. I live in the Rogue Valley in southern Oregon, which is an aluminum boat hotbed, so I can get it easily. If you find something you like but cant get it, I may be able to get it for you. Let me know.
Well, once again I feel like I gave more info than you probably need :-)
But I hope it helps. Let me know if you have any questions or concerns,
Joey

[D'ARTOIS]

Originally Posted by afinney

Hi. I want to build a power catamaran out of aluminum. I've found a design and have been reading aluminum boatbuilding. In the book they show some really cool chine extrusions that would make the whole process much easier. Anybody know where you can get these or is it only for the production boatbuilders?????

Any information would be appreciated.

Ask Alcoa or Kaiser dealers, they may help you.

i have 47 foot sloop built by aluminium plank system in Austria.
the system call pinical which invent by an austrian engineer.
go to web site pinical you can find more information.


david pyo

[CDBarry]

Contact Jorge Montes at Taco Metals, Miami FL for both stock and custom marine extrusions

800 707 7100

http://www.tacometals.com

[FAST FRED]

On two displacement steel boats we did , the hulls were IDENTICAL , except one had rolled chines.

Looked nice but was slower under all conditions than the hard chines.

Dont know why ,

FAST FRED

[Cian Groves]

Hi afinney,
Don't know if this will help, but please attached pdf file from Australia Ally extrusion manufacturer.

Cian

[austindba]

I second the question, are there US manufaturers of aluminum chine extrusions? I left emails and phone calls to Taco Metals- no one has returned my call. I have not found Pacific Metals on the internet. I have been researching for weeks and cannot find any company with chines in its catalog- although I have seen several companies that will fabricate it for me. This would be too expensive for a one-off builder... and I know that there are several hobbyist around... does anyone know of a US company (besides this Australia company) that distributes marine chine and gunnel extrusions?

I know I can be simple minded. But I would call ALUM. boat manu. till I got a helpfull one. BINGO. There are still some really decent companies out there. You just have not found one yet. You are told where the ALUM. manu. are.

[afinney]

do you know of a list on the internet of alum. boat manufacturers??? Let me know. Thanks for the reply and interest

There IS a list. I looked at it last week . Be back.

www.mels-place.com -----------That site will keep you busy for 2 days. A $ 50 bill would be nice.