I rigged a friends P19MX with a Tornado chute. There are some differences. 1) How stiff is your boat. Harry uses a Nacra bow foil to stiffen his hulls up for what he percieved as high loads with the chute and the small diameters of the cross beams. This means that the pole is quite low and required the construction of a dolphin striker for his pole.
Mounting cleats on the curved front beam requires molding base plates.
The other issue is finding a good hard point to sheet the spin off of. I don't remember where he put the hard point in. The optimal place on the outboard sheer of the hull may have been dicey without going in and beefing it up there.
Prior to the spin, he had to replace his front cross beam because it cracked under the new loads (or just wear and tear)
The beams are NOT beefy on this boat and the chute does cause the bows to visibly pinch. He sleeved his replacement beam to beef it up for the chute loads.
IMO, downsizing the jib and using a self tacker would be a huge ease of use improvment in the boat but I suspect you will loose a lot of horsepower this way. Moreover, Smyth used the Woodie batten to increase the sail area up high on the main. A T main won't have this feature and you will be limited to the standard halyard hoist height.
The clearance under the boom could be minimal and be a real pain in the butt for a recreational sailor. You may have to have the foot of the sail shortened to fit the boat adding to your cost. You are probably better off keeping the smyth MX main.
The mast is raked back as far as you can go and still have the mast rotate. This extreme rake (for this mast base) occasionaly requires a good kick to have it rotate around.
The boat with the MX Rig (Slightly smaller jib due to the bow foil) and Tornado chute is really powered up! The helm is quite heavy under chute (Normal without the chute up down wind) I don't understand this but I think the foils are just not quite right here. There is minimal lee helm with the chute up flying a hull. The boat does creek though. Perhaps the smaller jib and main will help matters here. You really miss the extra width in chop and your rear foot strap at the transom is not back far enough. You will die if you don't get weight back on the boat in order to lift the bows with the chute pulling.
The big picture question is WHY are you investing the money and time in adding a self tacking jib and spin system here in what must be a 10 year old boat. Selling as is and trading up to an Inter 20 would solve many of your design problems.
Harry's reasoning was he had 3 mor years of use left in his MX main, Prices of Inter 20's had yet to fall into his price range and a bad economy had made upgrading his boat out of the question for him personally. His upgrade works but it probably cost him more then he anticipated in rigging and time I think the boat would sail better with the orginal jib on it down wind. I think the huge jib and spin on a narrow boat make the slot easy to close off. He has not survived a really big blow yet. All in All he is quite please with his modifications.. The jury on the beach is still out on performance. Robbie D's used chute still looks better then the new I20 chutes out of the box. This past weekends race got cancelled with the hurricane.
Have fun with your planning and building.
Mark
