At least once or twice a week I am approached by someone who wants to have one of my composite cats done in aluminum. Usually they don’t care that the result will be up to 50% heavier, have more complicated interior, and have no insulation, compared to a composite one.
They like the idea that they can hit a rock and presumably not have to stop. There are a couple of assumptions in the mix that are usually not noted.
For whatever reason, alum. cats are usually done by fishboat builders. Fair and smooth is not even a concept, compared to what efficient catamarans must have. I recall hearing that Atlantic Fury was up to 3/4″ out in places.

For fishboats, that’s no big. They just pile on the horsepower to make up for it. With a rough bottom like that, driving around with rock damage is not an issue.  If the boat didn’t sink, nobody cares.  Until they have to pay for the fuel.

Again, for any cat to move well, it must not only be light, but also be extremely fair and smooth.  It doesn’t matter if it’s composite or aluminum, a gouge will slow the boat down and require more fuel.  And any unrepaired gouge will attract marine growth and further slow it down.  And again, the fishboat guys don’t care about efficiency.  We do.  The word catamaran means something very different to a fishboat builder, compared to a design that moves well.  The work-around for fishboat builders is to basically bog up a composite hull on the outside of the aluminum hull to make it fair enough.  But even with that is done, if the idea is that you can crash aluminum and not have to repair it is followed, you will be reducing that efficiency.

And always I wonder, if you have an aluminum cat with an added composite hull outside, and basically a composite hull inside to insulate it,  why the alumimum again?

In summary, smooth and fair are important for catamarans, but are often forgotten in building aluminum ones.  And don’t forget that there have been big advances in impact resistance of composite hulls compared to the polyester ones of 30 years ago.

I wasn’t gone. All last week, in fact since the last post, every time I tried to log onto this blog I got the message “access denied”. I see it’s finally fixed. I will have some posts shortly. I do have a couple of USCG emergencies today and tomorrow.

I just got word of the passing of Henk Bijl. Cancer claimed him April 21. Henk and Joke lived their dream. They built one of my 45′ cruising cats in 1999, I think it was, and have been offering clothing optional ocean cruises in the Caribbean ever since. I never met them, but they were delightful to work with. Zeevonk is for sale, with Allan Veth of Evecom.  www.multihull.nl

It looks like a couple more days of good epoxy weather here in Seattle. I will update all the comments here in a couple of days when the rain comes back. The parts are too big already to fit in the shed so I’m working outside. Materials are stored in shed.

Friend Steve Vogel retired from CSR Marine last Tuesday.  I realized its end of an era. I first met Steve when we both were livaboards at Kelly’s Landing some 33 years ago. Our two boats couldn’t have been more different.  He had a very traditional single hull wooden cruiser.   I had the lightweight trimaran.  He was often game (or crazy enough) to do races with me on my old tri Smoholla the Shaman. More than once he found himself crewing with me at Point No Point, after midnight, with a gale shrieking, as the boat is fully out of the water slugging to windward.
Or the day he ran me up my mast in a late December evening snowstorm, went back to his warm boat, and forgot about me. NPR was riveting. the mast was covered with ice and it was getting darker. I really had no options. I tried yelling. The snowfall got so heavy, all sound was absorbed. He remembered an hour later. He still laughs about that.
He will be cycling in France. Have good one Steve.

I had a great lunch yesterday with Scott MacIndoe of Fiberlay (and 5 other composites companies) yesterday. While he appears to be a regular businessman, I discovered that he really is a crazed inventor/chemist. The best kind.

His mind is seething with new inventions. Ones I could use include a new polyurethane fire proof coating and 2 part vinylester, of two equal parts. There must have been a dozen more that I have to remember.

Then there is the tunnel boring machine that also makes its own composite tunnel behind itself…

Still going through all the emails and orders from when I was gone. a little behind, but they will all go out this week.

Northwest fixture Fisheries Supply is no longer carrying knitted glass fabrics at its store, nor online.   http://www.fisheriessupply.com/
They tell me to go to Fiberlay, “Since that’s where we got it anyway.” www.fiberlay.com