Future TI Concept

I was looking at an overhead view of the TI today and I had a thought (scary I know). If the amas were lengthened by 2-3 feet, lengthen the hull by about 6", relocate the aft aka to behind the rear seat, reverse the rear aka braces so that they attach just in front if the rear seat, and add an additional front aka brace that attaches just in front if the front seat... This would allow for a couple of things IMO. 1) Larger amas mean more buoyancy reducing the chance of burying the leeward ama. It could also allow for more capacity. 2) You would now have much larger tramps (or hakas depending on your preference) and they would extend back to the rear seat. This would allow the rear seat to hike out along with the front seat.

Now the downside... The larger amas and tramps would add weight but I think it would be negligible.

Maybe I'm crazy. Thoughts?

_________________
2015 Hobie Tandem Island Hibiscus
"Third Normal Form"

• Trampolines
• Hobie cover
• Davis Spar Fly
• Kayakbob's Sprayskirts
• Spine Board Hakas

If I had a clean slate I think I would start with the main hull, if it were re-designed into more of a U shaped hull with a round stern, it would give the hull the ability to plane. I would raise the side walls quite a bit higher, I would also make the inside of the hull more like a trench (kind of like a Weta hull). I think the hull should be 20 ft long (it's too short presently to be able to add good fore sails). Definitely needs a better rudder (more like a cat rudder). I would definitely make the hull slightly narrower (forget about using it as a kayak (nobody uses it as a kayak anyway it seems)). I would also make the boat (with AMA's out) much wider, the boat is currently 10 ft wide, that's too narrow, 12 ft wide would give substantially much more flotation (the Windrider 17 is 12 ft wide). I wouldn't make the AMA's any bigger than what they currently are at the waterline (the design is actually quite good), but I would make them more bulbous above the waterline, and lengthen the back end like you suggest, but the extension would be completely above the water line. This way during normal sailing the AMA's would work like currently, but if increased flotation is needed the bulbous portion that's along for the ride up in the air (where it doesn't cause more drag) would take over giving you more reserve flotation.(there is not enough reserve flotation with the current design).
Adding a third AKA brace is probably not necessary, but having an extra bar going across in the area where the rod holders are currently about 3.5 ft wide would be nice. Tramp extensions could then be added so the person in the back seat has the ability to hike out (that would be huge), of course more substantial tramps (stronger) that are tapered in the front and the back (to act as spray skirts) would be a nice addition (just like what is currently on the Windrider 17's). You would be able to sit on any of the tramps (all load bearing).
As far as sails go I'm sure nobody will agree with me there. I would make the main sail exactly like the current sail (furling boomless) but around 120 sq ft (mostly taller), I wouldn't use a single sheet sail, I would make it a full wing sail based on the eppler 420 wing form. This is a super simple sail design that is completely furlable and looks no different from the current sail design. It would have more than double the power of the current sail. From a distance the sail looks no different from the current sail, and operates very similar (but way safer). I would definitely offer an optional 35-40 sq ft wing jib (the things really work and are simple to use and operate, and really safe). I would then add an optional roto furled code zero to the bow (around 140 sq ft), that would only be used occasionally on downwind (95% of the time your sailing faster than the wind with wing sails, so spinnakers only have limited use). With the wing main and jib the boat will easily sail 2x wind speed, and with the planning hull you shouldn't have that 8-10 mph upper speed limit (like the current design has).
I would keep the mirage drives for sure, and definitely make sure the new seats fit the boat (maybe 3 seats if there is room), I would design the boat around 1000 lbs load capacity and 6 passengers (2 in the seats, and 4 on the extra large heavy duty tramps). Wing seats (HAKA's) should be an option.
Yes the boat will be slightly heavier (240-260 lbs), but this is still way lighter than a Windrider 17 that weighs in well over 400 lbs, or most cats (most cats are over 350 lbs)
This thing would smoke pretty much anything out there on the market or on the drawing boards today ( IMO).
Its fun to dream
Bob

Outside of the hull and tramp changes I would say you just described your boat Bob

_________________
2015 Hobie Tandem Island Hibiscus
"Third Normal Form"

• Trampolines
• Hobie cover
• Davis Spar Fly
• Kayakbob's Sprayskirts
• Spine Board Hakas

Here's the thing - if the leeward ama doesn't bury, then at some point the center hull will fly. Granted this will depend on boat width and sail area as well, but generally boats that aren't intended to fly the center hull will have amas that do not have so much flotation as to prevent them from burying. Those are the two design concepts which most trimarans are built around - a design with enough ama flotation so that the center hull can fly, or less ama flotation so the ama will bury and prevent the center hull from flying.

If you fly the center hull, you'll get more speed, but you'll also need rudders and boards out on the amas instead of a single set on the hull (they don't work well if they're not in the water).

TI_Tom :
Yea guilty as charged, I really like the concept of the Tandem Island type of boat, which in my opinion is a departure from traditional recreational sailing boats. For example there are tons of Sunfish, Lasers and Laser II's out there and where I live in Sarasota Florida most of the year, there is a great deal of sailing going on, some weekends there are hundreds of sailboats out in the bay doing their regattas and sailing around bouys. I have little interest in that type of sailing. I consider our TI to be our new family boat (replacing our old Sea Ray powerboat that we could no longer afford to operate).

We just want a relatively safe boat that can get us where we want to go in a reasonable timeframe regardless of conditions (we typically have fairly low winds in this area), and the ability to use the boat for whatever we feel like doing. Not coming from a sailing background and the whole man vs sea thing ( I am definitely no sailing purist ( LOL)).
That's my story and I'm sticking with it.
Bob

The thought was not to fly the center hull, but rather slightly increase the speed by not completely burying the leeward ama. You could still bury it, but it would occur at a higher speed than it does now. I don't think that lengthening the ama by a couple of feet would produce enough buoyancy to fly something as heavy as the center hull and several adults hiked out on the windward tramp/haka.

Small, non-retractable, boards on the amas wouldn't be a bad idea though (8"-12"?). Or even perhaps retractable, but spring loaded (they are always down, but if pushed they would retract into a slot in the underside of the ama).

I'm not a marine engineer, so I don't know if any of this is even feasible.

_________________
2015 Hobie Tandem Island Hibiscus
"Third Normal Form"

• Trampolines
• Hobie cover
• Davis Spar Fly
• Kayakbob's Sprayskirts
• Spine Board Hakas

Bob:

I understand where you're coming from. My parents owned a 22' Ranger when I was a kid. As much as I enjoyed sailing with them, it was a pain to put that boat in and out of the water with the giant 6' lead keel and all. That's why I like the concept of using this TI as my family boat. Way easier to put it in for an afternoon of fun. My wife and I have also enjoyed kayaking, but with a family you end up having to haul around 2-4 kayaks just to get everyone on the water. This is the best of both worlds. I'm not saying the current design is incapable, just that I could see some possible sailing improvements without really sacrificing the "kayak" side of things.

_________________
2015 Hobie Tandem Island Hibiscus
"Third Normal Form"

• Trampolines
• Hobie cover
• Davis Spar Fly
• Kayakbob's Sprayskirts
• Spine Board Hakas

TI_Tom:
Here is one of the best videos I have found of a family using the Tandem Island, Hobie invented a whole new boat category in my opinion.

Still one of my favorite videos of all time.
https://www.youtube.com/watch?v=Pb4orK9MLXE


Bob

That was one of the videos that I used to sell the boat to my wife.

_________________
2015 Hobie Tandem Island Hibiscus
"Third Normal Form"

• Trampolines
• Hobie cover
• Davis Spar Fly
• Kayakbob's Sprayskirts
• Spine Board Hakas

Ok, I suck at photoshop and used paint to do these real quick. But here are concepts of what I was talking about.
Here is the stretched amas with repositioned akas.


Small center boards on amas.

_________________
2015 Hobie Tandem Island Hibiscus
"Third Normal Form"

• Trampolines
• Hobie cover
• Davis Spar Fly
• Kayakbob's Sprayskirts
• Spine Board Hakas

We have a number of ongoing projects that might be the next big Island type product someday. We have been looking at higher performance sailing with aux MirageDrive support for some time now. Exciting stuff!

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

…go on.

Yes, do tell Matt...

_________________
2015 Hobie Tandem Island Hibiscus
"Third Normal Form"

• Trampolines
• Hobie cover
• Davis Spar Fly
• Kayakbob's Sprayskirts
• Spine Board Hakas

Can't... But rest assured... we all love having fun and love sailing! I can say... not likely for next year.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

hahaha, well it was worth a shot.