Leigh Hutchins in Canada is modifying an older Gougeon A-cat and is seeking help on the project. I know the questions were posted on the usaca.info site but no one has yet responded. maybe someone here can help. Here are the questions and the link to boatdesign.net where the original posting is.
I have a late 90's A cat which is going on a carbon diet. The new beams have prompted a configuration change so here are the questions.

1) How far back should the main beam go?

2) What is the normal hull cant angle?

3) Once I cant the hulls where do I measure the centerlines of the hulls so I don't end up toed in or out? Do I use the static waterline plane as the center of rotation?

The static hull immersion will no longer be symmetric. Should this impact my alignment decision?

Leigh
http://www.boatdesign.net/forums/multihulls/new-beams-my-cat-26879.html

77 views and no one has anything to say that could help Leigh out. I am just a newbie is the class and have offered what I could and after that suggested that Leigh post here and on the usaca.info site. You guys are the best minds out there and Leigh is trying to get a boat modified and active within the class. If you have thoughts from your years in the class any in modifying your own boats, please help. Thanks!

Short answers as i'm on my phone.

Moving the beam back will effect how you sail the boat. You'll need to stand well forward up wind so don't go crazy. new hulls have different bouyancy distrubution to suit.

To determine appropriae hull cant:

cant=1/2*(tan(-1)(hull draft/hull seperation)

To set parallel mark points on the bow and transom at desired upwind trim before removing existing beams. Remember if you cant get them perfect, toe in is better than toe out.

Windswept, don't be to harsh. Yes 77 views but I am sure like myself, most people are viewing posts out of interest. Yes some of the viewers are A cat guys but probably don't feel they are in a position to give advice on boat design. I am sure everyone has an opinion but not confident enough to advise.

The A3, Ashby, EVO and modified XJ design have moved the beam back about 14 cm. Most have about the same canted hull angle.
Several have glued the front beam in with epoxy, some with 5200.
Also- the 63-412 foil is an assymetric shape designed to lift. What are you intending with that?

What will you do with the daggerboard wells? Move back 14 cm also or less? Cant in, out, curved boards?? Its a new world.
My Cal Fuller woodie in thumbnail <- has a Hobie 16 mast section crossbar and is at 200 pounds.

Sorry, I do not mean to be so harsh. I found leigh on boatdesign.net who was looking for help far beyond my knowledge and directed Leigh to both sites for help. I will be more patient in the future, but thank all of you for helping.

Tom,
If you are in contact with Leigh, send him my email. I have mast and sail and daggerboards he might want. I also have a 2 part Proset epoxy gun he can borrow.

Bill
wjvining at yahoo