A Hobie disclaimer here is understandable. Although it might hurt Ama sales.
And my barrister advises I should add one of my own, so: "Any aftermarket modifications of Hobie products depicted here are the work of a retired engineering genius with an overactive imagination and way too much time and money on his hands. They are not intended as anything other than pure personal amusement. Neither NOHUHU nor Batman Enterprises (AKA "Hawaiian Skunkworks") endorses this or any other modification of any ocean going craft for the sole purpose of achieving more speed, utility or pleasure from said craft. Standard text messaging rates apply, your mileage may vary, call your doctor immediately if your erection last longer than 4 hours."
If the TI hull and various mounting points are substantially reinforced beyond the 2011 AI's, then there is something to be said for the TI having a greater stress tolerance. We know this is designed in somewhere. The TI's length, sail and rudder are much larger. These create greater stresses than an AI would ever experience. Although, if the Akas are essentially the same hardware, then those are not the concern.
I would tend to think that elongated Amas would help distribute and mitigate normal sailing loads. On the Bat Yak, the longer Amas enhanced the AI's tracking, stability and floatation.
The main reason for testing this mod was to add aft buoyancy and make the rear deck seating safer and more effective in Hawaiian waters. Most of the design goals were achieved. Adding more gear capacity or another passenger is an unintended bonus.
Everything has a trade off. As Matt points out, longer Amas add stabilty, but could increase stress on the load bearing points at times. It might also convert that added energy into more forward motion (speed), but the jury is out on this one.
Likewise, burying an Ama may be a "safety" feature, but it also stresses the members. Thus, submerging a longer Ama could produce a larger sudden drag. It might be easier to blow out a shear pin, I suppose. But again, the addition of the Bat Bench (or tramps) controls this. We will keep an eye out for these problems. (My lawyer thanks your lawyer Matt)
Funny how the first thing we do after bringing our new Hobies home is look for ways to customize them. Sometimes we don't know when to stop. Judging by our passion for hottrodding, I think the Ama genie is out of the bottle now to stay.
That's understandable too. After all, it is called the "Adventure". Not the "Tercel."