Ricelli's Aluminum Gift

[Chris Ostlind]

As a head's-up to other boatdesign.net followers, regular forum contributor, Paul Ricelli's design of a beautiful, aluminum, day sailing ketch has been published at Duckworks boatbuilder's magazine.

http://www.duckworksmagazine.com/06/...trel/index.htm

The Kestrel is an inspired, sweet look at an enthusiasts preliminary design effort for family outings along the Oregon coast and in land waterways.

This is a terrific example of a simple to build boat that will provide many years of lasting satisfaction for the new owners. Great work, Paul.

Chris Ostlind
Lunada Design

[D'ARTOIS]

Paul's designs are "the not every day's approach" of an original designer, and shipbuilding artist. Before I was swept into my present environment, I was very interested to build one of his designs. But who knows.....
Before all, I am a afficionado of traditional hulls and wooden boats in particular.
That Paul goes alu, is maybe a new way of making light and fast funsailers that will have a timeless quality and charisma.....

[longliner45]

How do aluminum boat hulls hold up to electrolisis in salt water?I know steel boats have high maintanance ,and most have an arc welder on board . Im not challanging the design I m just curios. longliner

[PAR]

Aluminum holds up very well in the marine environment, if the appropriate precautions are taken. Aside from the obvious difficulties with dissimilar metals which can be engineered around reasonably easily, aluminum is less sensitive to stress risers, doesn't need additional plate thickness to account for corrosion, no rust, faster welding, no shape compromises, easier to work then steel, of course it light weight and a lack of attraction to marine beasties, plus several other things I can think of, off the top off my head.

This boat could easily be a cold molded, tape and seam or other construction method with minimal effort.

[artemis]

A drop dead gorgeous boat that is ideal for her home port. I've lived in the PacNW for most of my life - currently (for 25 years) in Portland, Oregon and know what this design will be subjected to and have to float over. I'm going to assume that when you researched her cruising waters, you found similarities to areas of Florida. Job well done.

[PAR]

Thanks Artemis, Brien and Chris. We have different wind patterns and less junk that can hole your boat (here in Florida) then they do, but similar sailing conditions in many ways. The scantlings are quite stout for a craft of this size, but submerged stumps and barely floating logs can be tough on a lightly built boat. The image that appears first in the DuckWorks article, is of an earlier hull version. The "C" (seen in the upper left corner) became the choice of several optional rigs. That hull isn't much like the other two shown (the finished product), having much more displacement and wetted area. It still had the features of the basic requirements, but was a very different shape.

I've a few requests for a tape and seam version and will work them up. The plywood boat will weigh about the same, but have considerably less parts, as is often the case in conversion to that construction type.

She should sail quite well though varying conditions (one of the design requirements) having a number of hoist and reefing options. This hull could also carry a small, sitting headroom (barely) cabin, enough to get out of the rain or do some camp cruising, without harming her abilities to much.

[longliner45]

why would someone want a plywood version? ; yes she is beautiful

plus several other things I can think of

Higher flashpoint than wood or glass/resin!

Cheers!

[SamSam]

Originally Posted by PAR

Aluminum holds up very well in the marine environment, if the appropriate precautions are taken. aluminum doesn't need additional plate thickness to account for corrosion, a lack of attraction to marine beasties,

Very nice looking boat, it seems like it should work as good as it looks! Concerning aluminum, I edited your post to the above. What are the appropriate precautions? Everything aluminum I've seen in salt water has real problems with corrosion. Although 1/8" thickness is a big help, if it does corrode, either on the outside or the inside in hard/ impossible to reach nooks and crannies, the corrosion would seem to eat up half of that thickness. Any additional corrosion at the same spots would seem to leave the hull susceptible to pinholes. Why is it not attractive to marine beasties? I've always kind of figured Kryptonite or an open flame was the only thing they might not bother. Sam

[PAR]

If you're having corrosion difficulties, then the boat wasn't, designed or built properly. Most aluminum work boats are unpainted and live continuously in the brine. Using Delta Couple to join dissimilar materials and well thought out connections (threaded inserts, anodes of sufficient area, UHMWPE and HDPE bushings, etc.) will keep the boat from eating itself apart. This boat has lead ballast, but it's covered in 3 layers of cloth set in epoxy and is sitting on a wooden channel (well isolated), so the likelihood of it acting like a battery is remote.

Stray electrical current is the biggest problem in metal boats. Complying with ABYCS will insure a much longer life span for metal boats. Common problems are cheating the ground bond to the hull, through engine mount bolts, instrumentation using the sender contact with the block as ground, non isolated engine mounts, wire reinforced hoses that make contact at both ends, providing short to ground, etc. Much effort must be taken to isolate paths to ground. Bonding the AC ground to the DC ground bus, but no other location.

Aluminum will oxidize, then this serves to protect the surface from further attack. Marine life will grow on just about anything eventually, but aluminum is much less appetizing to them then other materials. Aluminum isn't subject to assault by sulfate reducing bacteria, which can eat up a steel tank or bilge very quickly, like right through 1/4" plate in a single year!

[Guillermo]

Nice design, Par. What do you think about building her in cupronickel?

[PAR]

Ouch, if you think aluminum was costly, though in larger vessels (over 45' - 50') copper-nickel becomes competitive. I'm assuming this is the material you mentioned Guillermo (I'm glad you like Kestrel)? Copper-nickel alloy is quite similar in strength to aluminum, but weighs more then steel. It doesn't oxidize at all, it doesn't require any bottom paint, being nearly foul proof, for the average life of the boat! You don't even have to paint the stuff. The fuel savings, from an always clean bottom, can pay for the extra material cost pretty quickly in commercial vessels, where the few examples I've seen, have been used as tugs or other working craft.

[Wellydeckhand]

Mmmm........ Copper-Nickel...... Rust proof..... any builder in asia used it? Where can u get in Asia?....... or have to order it in America...... whats the grade.........? What welding usually used? need shielding gas? ........ anymore info thanks a million...... always nice to know alternative material.

[FAST FRED]

"Stray electrical current is the biggest problem in metal boats. Complying with ABYCS will insure a much longer life span for metal boats. "

That stray electrical current can come from the boat in the next slip , or a lazy electrician that dropped copper wire cut offs in the bilge.

Vacum clean a new boats bilges , spray water about & do it again.

Installing an isolation transformer is not too expensive and really is the "best" way to get rid of any stray currents aboard.

Either anchor 100 yards from any marina , or get a protective unit installed, Dont remember if there Annode or Cathode , whatever , they can protect your aluminum vessel from the house hold "power cord" the guy 3 slips down uses.

FAST FRED

[longliner45]

I still would like to know ,is there an advantage to this boat being made of plywood?