car_guy wrote:
As a 21SE owner would it be feasible to cut down the beams to legal width? I understand the tramp and shrouds would need to be shortened but that doesn't seam too difficult. Would loosing the beam kill performance?
Reducing the beam on a catamaran is a fairly straight forward mechanical task. You are sacrificing a percentage of your righting moment but not much else in the way of performance. Righting moment is a function of width and also a function of ballast. If you give up width you can always make up righting moment with more ballast ie heavier crew. You can also add wings to gain back width. Trap out on the wings and you add a bunch of righting moment.
The most critical part of the job is dealing with the dolphin striker. The dolphin striker supports the compression loads of the mast. You have to get this right. (On Supercats this is an easy task, Aquarius sells an internal striker that slips into the front beam.) Dealing with the tramp is easy, cut the middle, fold it back, add some grommets and center lacing, done.
The side stays and forestay can all be reused, how? Easy, Remove the mast hound, do some geometry calcs, then measure precisely, you reattach the hound to the mast, somewhere between 1-2 inches higher on the mast, this will take up all the slack in the stays. Trust me it is not much. (you will have to shorten the bridle wires to reuse the forestay, these are the only two wires that need to be shortened or custom made) Don't forget to plug the unused holes on the mast to reseal it.
I narrowed a Supercat 20 from 12' down to 9' (giving up 25% of the original righting moment) and do not have any regret what-so-ever. It is a terrific, fun, fast and easily trailered boat.
Edited by havliii on Mar 30, 2016 - 12:04 AM.
Hobie already did it with the H21 sc. It's "formula" hull was designed for racing (H21se) and with wings is a comfortable 13' wide cat for 3-4 adults. With wings off it's a standard 8'-6" width for trailering. The large amount of dry storage make it ideal for coastal camping/recreational sailing. The downside of being underpowered can be solved with a more efficient/powerful square top main and reacher which is what we did. All 3 sails are roller furling which makes for easy handling and we have a 2hp Honda outboard that gets us in and out of crowded launch areas easily. We searched for a year to identify the ideal beach cat for a seasoned big cat/H18/Nacra 5.2,5.8 sailor to introduce young kids to sailing comfortably, without giving up speed. We find the H21 sc to be ideal for several days of coastal hopping in Baja or out to the Channel Islands. So far we love the boat and can rig it in about an hour from the trailer. My family loves the speed and simple uncluttered layout and sail controls. Trampolines are clean and clear for guest comfort and we wrapped the wings under the mesh in 3/8" EVA foam to cushion the tubular frames. If you are not racing, the boat is plenty fast, even for me, and can handle a wide range of wind conditions due to its lower 29 foot mast height and boom furling main. Hobie made an optional boom tent for overnighting on the main tramp. The boat has the simplicity and indestructible toughness of a smaller Hobie with the carrying capacity of a 21 foot hull. I traded a little speed and lightness for a lot of comfort and turning on my kids to some epic cat sailing adventures. I'm surprised that there are not other cats like the H21sc that fill a niche for those like myself that like sailing long distances on my cats.