Who knew? A KHSD 48 carrying passengers  in Branson, MO.  See http://www.stateparkmarina.com/spirit.php

Here is a simple little wind load calculator that I seem to use all the time for things. http://www.sailingusa.info/cal_wind_load.htm

Got a nice write-up in Northwest Yachting magazine. May issue.  By Peter Marsh.  The anchor article is about Schooner Creek Boatyard. They have built several KHSD charter cats. I had forgotten that Peter was such a unique historian to write this from his perspective.   No slacker stringer could have synthesized so much history.  Firsthand.  And yes I do know that first picture is of Profligate.  No big.

It had a link, but the link only goes to the most recent issue.  And back issues lock you into a huge PDF.  I bailed at 30 mg.

The old kauaifishing website no longer worked when I last looked.
Now it is http://napaliseabreezetours.com/
He offers some great fishing and sightseeing from his KHSD 34 powercat. Great mileage and a smooth ride. Yeah displacement hulls!  Told me he once saw Holo Holo slicing through the waves one day when the motion was slamming the malahini silly on the other boats.  Said he wanted a boat like that but smaller.  It doesn’t draw much either.

Multihulls mag sent me this. Annapolis.
http://www.performancecruising.com/cruisers_university/university_rsvp.html

BASIC COMPOSITE & MOLD MAKING TRAINING CLASSES

Saturday, May 7th 2011
9am – 3pm

Fiberlay – Seattle
24 South Idaho Street, Seattle WA 98134

$50 per person
(lunch included)

Call for David Chamberlain for details 206-782-0660 or
Email: david@fiberlay.com

SCHEDULE
9am – 10am
Mold Making with Polyurethanes, Silicones & other
10am – 10:15am
Break
10:15am – 1pm
General Composite Materials, Equipment & Infusion Process
1pm
Lunch
1 – 3pm
Questions, Retail Open to Class

The first complete picture of the new 21′ powercat shuttle in production in China now.

Conventional wisdom is that as soon as a multi is built here, it sails for warmer climates. Or that they are all store-bought F-boats that have been capsized at least once.
Actually there are a surprising number of KHSD multihulls building and sailing in this area. None have capsized so far, and the owners are not clubbie so they are not on club memberships. In no particular order, and I must have forgotten several, and I know I’m forgetting a bundle of little daysailors:
49′ cat – Poulsbo
Formula 40 tri- Seattle, for now
45′ cat – Bellingham
45′ cat – Seattle
63’/65′ trimaran – Marysville
56′ cat – Port Angeles
56′ cat – Portland,OR
Chaak 49′ tri – Seattle
Proa 26′ – San Juans
Proa 24′ – Seattle
26′ tri – Bellingham
36′ daycharter cat – Blaine
37′ tri – Seattle
52′ tri – eastside, may not still be on
37′ tri – Bellingham
40′ tri – Bellingham or farther
65′ catamaran ferry – Everett

31′ tri -Port Townsend

27 cat – Seattle

40′ powercat – Tri Cities, OK thats very greater Puget sound.

How about that? Who knew? Let me know if I have forgotten anyone.

To get more room in a hull space people often want to substitute a hat section layup for a bulkhead. So how do they compare structurally?
First, ABS ORY tells me that I can use some of the hull skin in the laminate calculations. But only a flange width of 18 times the skin thickness, plus the base width of the internal part.  The skin thickness is assumed to be 0.15″.
The basic bulkhead is assumed to be an inch wide so I’m allowed to use about 4″ of the flange width. I will assume the bulkhead is 6″ tall and has 0.1″ laminate faces.

For a hat section I assume that base is about 6″. I’ll again use a skin thickness of 0.15″, giving me about 3″ so a total flange width of 9″. I give it a 3″ wide inside flange and sides at 45 degrees. Those parts are also 0.1″ thick. I assume all parts are of equal strength.

The original bulkhead gave a section modulus SM of 2.1 inches to the third power (2.1 in^3).
The hat section only gives SM of 1.33 in^3. If I thicken all the hat parts to 0.13″ (4 times 17 oz biaxial) it still only gives a SM of 1.6 in^3.  5 layers of biaxial will give a SM of 2 in^3.
Conclusion. Like magical catamaran beams, hat sections take more material to achieve the same strength as a bulkhead.