Modified Tigercat

Hello All,

In 2004 I completed a modified version of the Robert Harris Tigercat started in 1968. It has the published lines of the Tigercat except for flat decks on the floats. I decided to use a center mounted single centerboard like Stiletto to avoid the hazards of bottom collisions in small lakes. The sail rig is Hobie 16. The front is a trampolene and the rear is rigid hollow plastic decking planks attached to the hulls and the center aluminum truss box for the swinging centerboard by removable screws. The main beam, a 5.5" diameter 1/4" 6061-T6 aluminum pipe, was located so the boat would have weather helm for safety. I have digital images of the entire project. My question to the group is about the sailing characteristics in a moderate breeze. The fastest direction is across the true wind with the sails close hauled. The boat very rapidly tacks back to the reverse course. Are these sailing characteristics characteristic of a catamaran or are they due to the single, center mounted swinging centerboard? It leaves a rolling wake across our 100 acre lake. Regards, Ted

 

You can post the pics, if you are willing. Do you have any of it sailing? It would be helpful to have sailing pics plus plan and profile photos or drawings.... I would be interested to see. Otherwise you can probably only get textbook type answers, such as this:
Yes it sounds like a cat. Almost any boat that's fast will have the sheets somewhere between the end of the traveler and block and block (close hauled) when up and running on its fastest point of sail (usually between 90 and 160 deg) due to apparent wind. If it tacks fast then it must be well balanced -congratulations!

On the other hand if you meant it tacks when you do not want it to, "on its own," it is likely because of the centerboard installation. For example if the board was meant to be hung from a hull, it may be too short by the depth of the hull...

One question -How does the steering change related to the angle of the centerboard? Another question -Does the CB just pivot up and down conventionally or does it cant from side to side?

 

Tigercat

I have been sailing the boat very successfully for 3 seasons. The boat tacks only when desired. Rapid movement of the rudders 45 degrees does not cause a stall, only a very rapid turn. The weather helm is such as to require the centerboard to be raked back when sasiling only with the main. I need to know what the photo image file sizes and numbers are limited to by the forum.
I can sail with 8 people on board. The wetted surface of the hulls is the same as published in Modern Sailing Catamarans. The drawings were photographed to make templates. A plaster male was made first and then a two piece female mold was made from fiberglass polyester resin. The hulls are molded fiberglass with aluminum angle trusses and corner stringers. These are pop rivited and West System epoxied to the hulls. The flat 1/4" mahogany plywood decks are fully wrapped with the West System. The top layer overlapping the edges was applied after pop riviting to the aluminum angles along with urethane adhesive. There are 1/2" thick bulkheads of pressure treated plywood coated with epoxy below the two piece clamps for the cross beam pipes. The hulls are assembled in the water each season. Regards, Ted