Jeeze guys talk about controversy.
I did that AKA extension mod quite a while ago and just mentioned it it passing, I would never expect anyone else to do any of the mods I do. Everything I do is solely for my own purposes, and all intended to increase the efficiency of my human powered peddle craft to the point where I can expend as much energy as I can personally produce as a really old overweight way out of shape human (realistically I can produce right around 1/2 horsepower peddling at around 45 cpm (cycle per minute) for around 10-12 hrs). If you equate that to peddling a TI under human power with no wind or sails on flat water with no current the boat goes 2-3 miles per hour. So peddling 10 hours steady lets say down the Mississippi ( about 1200 miles in total) I can cover around 20-25 miles per day. I can't count on any wind or current because wind and current are both highly unpredictable. Or lets say I want to go from Sarasota to Key west following the intercoastal, then island hop the keys (staying close to shore). In Florida you sometimes have wind, but 80% of the time here the wind is under 7mph, (especially at night). Also if there is any wind especially if the wind is against you, (predominant winds here are from the south),in most cases this hurts, not helps you, (most of the time this is the case). So it is critically important to have a boat who's efficiency increases upwind, (not decreases), and you should not need to tack back and forth which is wasteful, (think about it sailing at say 4mph into the wind 50 degrees off the wind, your forward progress is only around 2mph (VMG, ...velocity made good is the correct term). Plus there is no way to tack thru narrow channels or rivers. Also if the river is surrounded by trees the wind is blocked most of the time. This circumstance accounts for around 70% of my time. I am no athlete by any stretch of anyones imagination, and have zero desire to over expend my own physical abilities just to do something, there really is no point, ( this is why we have brains, lol)), I got nothin to prove to anyone, I couldn't care less what anyone is using their boat for, my only goal is to design the boat I want specifically for my own purposes, revolving around just my own limited physical abilities, and no one elses, (lol everyone else can and will do as they please). My goal has not changed, (been workin on it for 7 yrs now). I want a human powered craft that averages 12mph vmg cruise speed regardless of actual natural wind speed and direction, (specifically because you can't predict the wind). I specifically want to be able to travel 300 miles non stop in under 24 hrs, in any conditions encountered. The reason for the 24hrs is because I'm an insulin dependent diabetic, and that's the longest I can go without insulin. Also because of my disability, I can't sleep on the ground ( like in a tent). With my gas hybrid engines I need a least 100mpg, (ie... 3 gallons of fuel on board to be able to go 300 miles non stop), original goal was 150 mpg, but I want to use off the shelf engines vs inventing a new type engine.
Eventually the supplimental propulsion will be converted to solar/battery/electric, and fuel cell, but that tech is not yet readily available. Or if we are traversing the 1200 mile or so Mississippi ( on my bucket list) I need to cover a minimum of 100 to 125 miles per day under human power. But all has to be within my own physical ability (no one else's, everyone else can do as they please). At the same time the boat cannot be delicate, it needs to be able to operate equally well in high seas and less than ideal conditions, and utilize efficiently any wind I happen on to be able to amplify my speed beyond the stated minimums, in otherwords in favorable winds I would like to cruise 15-20 mph and still be able to operate the boat safely in up to around 25mph winds and 3-4ft seas (open ocean). If conditions change to small craft advisory, I also need the ability to get off the water and safely to shore at as high a speed as possible. I have no intent to ever operate the boat in small craft advisory, my intent is to make for shore and safety, I'm not crazy, I don't want to die (lol).
My chosen platform is the Hobie Tandem Island for several reasons. First off is the dual mirage drive system is designed from the ground up, in so my wife and I can both pedal. Secondly the length to width ratio of the sleek hull is at least 8 to 1. Only slight mods are required to make the hull a planing type hull ( kind of neccessary for efficiency above 8 mph). Thirdly because my boat has additional sail area (up to 260 sq ft) a little more AMA flotation is desired when in sailing mode, but more importantly in pedal mode now the AMA's are completely out of the water they don't create any drag at all, (they hover just over the water, and sometimes the rear 1/3 of the AMA planes on the water when operating at cruise speed ( currently 8-10mph) with side load on the wings and sails without creating additional drag on the boat, (kinda important to me anyway). Since we are in the seat peddling, it's kinda hard to hike out so the AMA's are setup higher in the air and a wider footprint from normal to increase efficiency, no other reason. Obviously we don't want our AMA's to ever touch the water at all, but if they have to, might as well make them as efficient as possibe, (planing on top of the water, not dragging thru the water). Widening the boat and raising the AMA's accomplishes all that. Hobies AMA design itself is masterful. Then the main reason, I happen to like the boat and "it's the only boat we own", so when not working on my stupid goals crap, we just use the darn thing as our only family boat, plus being kayakers we use the kayak part, probably half the time. And since we sold our searay, we need the boat for diving and snorkling , (which is our favorite pastime), and we happen to live in SWFL and the keys so we can do all this stuff year round, also we travel alot, we have about 250k miles with our Hobies on the roof and camper in tow.
Please don't read in any other purposes for my AMA extensions beyond what goals I outlined above, specifically and only for my stated purpose, (above) is the only reason the mod was made. I did the mod quite a while back and just mentioned it in passing, and that it ended up working way better than even I imagined, (who knew , (lol)).
Obviously the whole concept revolves around my wing designs, I'm still a couple design generations away from my stated goal (12-14mph cruise under human power with a minimum supplimental propulsion @150 mpg, regardless of wind conditions, ( basically 300 mile non stop range in under 24 hrs)). The platform I've been running for 3 yrs now is pretty maxxed out at 8-10 mph cruise, at 60-80 mpg, fun as heck but no cigar, I still have a ton of fundimental wing design work to do. Will I ever achieve my stated goal, of course not.... but it sure is a lot of fun tryin, and practicing (lol, keeps me in shape). Plus we get to use a really cool and fun boat for everything else we can dream up, (lol, since it's the only boat we got). FE
Sorry for the long response, sometimes things can't be explained easily, sorry if I offended anyone.
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