New 37′ Cat Build

Got a bit of work done. New design book about there, needing only a couple of pictures that were still back at the office. I’m also kind of aiming the book at the future when its only available on Amazon, so putting in the hot links and so on.
But also created a new design being built soon up in Anacortes. A 37′ foam/glass cat with an aeroesque unstayed carbon mast. Builder is Jim Betts again.


More Kaleava

I don’t think I have posted this one before. Another shot of Kevin Millet’s 48′ cruising cat. It’s Kevin’s design based on his charter cats, but I did the hulls. Is crazy fast. If I may quote a witness ” You popped that sail up at the start line and smoked the rest of the fleet.”


Unexpected Sarabi Picture

I was looking for Kevin’s Face page to send some lines drawings to while travelling. I stumbled onto this picture of my 56 aero rig catamaran design Sarabi taken by a friend of Kevin’s, in Sidney, AU.  Funny story. In this cat’s design phase, Philbrook was so impressed with Kevin’s hulls I designed, that he wanted some just like them but bigger. Good stuff.


Fassmer Tender Catamarans- Stuff Done Wrong

Another page on Stuff Done Wrong. These Fassmer catamaran lifeboat/tenders are amazingly bad, in my firsthand opinion.  They were clearly designed by someone who had no experience in catamarans. And the contract must have been huge as there are so many.
Notice in the picture that with only a few passengers, the bridgedeck is already underwater.  It really is a catamaran.  As a lifeboat,it would be OK. You are lucky to be alive. As a tender, I doubt if it could be worse for the job. A tender’s job is to ferry the elderly and infirm from the cruise ship to the shore. Half the passengers had difficulty walking on dry land anyway. The Fass has an ugly combination of pitch and heave inducing features. The bow overhang shortens the waterline, allowing more pitch. (It kind of looks like what a monohull designer thinks a catamaran should be looking like.)   Aft, the draft is cut away for the prop, and that makes pitch worse. The low bridgedeck gets lifted by almost any wave, and the elderly really have to hang on. I was on one in only half meter waves and it was tilting up to 20 degrees, provoking moans from the passengers.
It is only 36.5’ (11.15m) long but weighs 26,455 lbs (12,000 kg). 300 hp gives 10 knots if you are lucky. Even within the envelope requirements, a real catamaran designer could have done so much better.



Notes on Materials Spreadsheet

The KHSD materials spreadsheet is a very powerful tool to accurately predict what material amounts will be needed in a build. On any design, I query each part of the 3D model for the area of that part, then that is entered into the spreadsheet. I know that the cool kids would build active links between the model and the spreadsheet but I’m not there yet.
This spreadsheet now is the result of years of improvement; hiring licensed naval architects, excel geeks, and just keeping it moving forward. I see even more flexibility and power for it as soon as I get some time. I see extremely complex materials lists linking to another boat parts spreadsheet. When I get time.
A couple of things; I do not count waste in it. I understand that amount to be 20%. I recall that when Sarabi was built, Barry kept accurate records. “your spreadsheet was 20% under” he told me. Yes. You can put a little cell at the end to compute that waste amount.
Along the bottom left center of the spreadsheet are little tabs. They say “master” “plywood”  ”glass lam” “exotic”and  “core”. Click on each one to see the amounts of that type of material. Go ahead and try it. I do often get asked where the other materials are. Try the different tabs.
Not all the tabs apply to you. But they are usually full. I have gotten angry calls demanding to know what all that damn wood is doing on their composite design. Just use the tabs that apply. I have sometimes stripped out the tabs that don’t apply, but that is a mistake. Even after more than 30 years, CM boats are as popular as they ever were. If the plywood is stripped out of a spreadsheet for example, and later needed, it would take hours to replace all of it. So don’t freak out. Just use the tabs that apply to you.
A powerful spreadsheet like this can get a damaged cell just by surfing around on it. A damaged cell can lie to you with authority. Check that regularly. To check for damage, go to any summary cell and right click. It will list the cells that contribute to it and color light all of them up the spreadsheet. If anything looks funny, check it that way.