The ultimate Tandem Island (hydrofoils, Spinnaker, jib, etc)

It's not a tight fit on the mast but the bolt sitting in the slot at the top of the mast keeps it steady. It only covers the top 6" of the mast so it won't impact on how the mast flexes.

I will hopefully be working on the bowsprit over the weekend.

John:
I just wrapped some electrical tape around the end of the mast to get the fit a little better with the pipe and the mast. The whole works has never been removed from my boat(s) in 3 1/2 yrs and over 6000 sailing miles in all kinds of conditions.
The only time I get scared with the setup is if I raise the 135 sq ft spinnaker on a downwind in 20 mph+ winds, the ride is so wild and scary that I don't do it often. The trick to achieving 18-20 mph speeds is you have to get the boat going downwind first (with the other sails), then while moving I unfurl the spinnaker. It only seems to work on a downwind with the wind coming from 150 to 210 degrees (downwind). Unfortunately at those speeds any sudden hard rudder movement simply snaps the rudder off (breaking the rudder pin, I have broken several). Before trying to turn off the wind or slowing down the spinnaker must be furled. Because the spinnaker is mounted so far forward on the end of the bow sprit, the fore sails are all angled quite a bit (this is important in the design), what this does is create the required lift to get the front of the bow completely out of the water. Before getting the bow sprit I had hydrofoils under the boat to raise the bow out of the water, but since adding the bow sprit I no longer needed the hydrofoils, so I removed them and they are sitting in the garage now.
It's actually kind of funny before adding the foils and the bow sprit, on a fast downwind the entire bow would submerge under water and just stay under until I released the sails (what I called nautilus mode). Talk about a wet ride .
The boat itself is not really designed for those kinds of speeds ( DAH) so being cautious is pretty important. The other potential problem that can arise,
you will need to add re-enforcing rope onto the AMA's to prevent the AMA's from folding back. I use 1/4" nylon (stretchy) rope clipped to the center stainless padeyes on the AMA's, then up to the outer AKA hull supports on the front AKA bar. These ropes are also important, if you are going any kind of speed and you bury an AMA at that speed, it can literally rip the AMA's off, it's best to hike out and try and balance the boat trying to keep the AMA's out of the water as much as possible. These ropes just stay with the hull and when not being used I just stuff the ends into the mesh pockets, when rigging the boat I just clip them onto the padeye when connecting the tramps (takes all of 2 seconds). The rope also prevents the AMA's from coming off and rattling around on the bungies.
Other than the few minor changes we have talked about, the rest of my TI is completely stock, and to be honest I haven't really made any additional changes in a very long time (besides the wing sail which I did last spring), I just use the heck out of my stuff, and have as much fun as you can have legally (LOL).

It sounds like you are well on your way to making a "Super Island", you won't regret it, I'm having the time of my life with mine.
Good luck
Bob

I did a test fit this morning to see how the mast topper performed furling/unfurling the mail sail. It all seemed to work no problems but I could notice the increased resistance.

I'm thinking that this jib might be a bit too big for the AI? If I do use this one I will need to have it attached around 300mm (6") forward of the bow?

I would definitely try it out in lighter winds just as is and see how it does. You can just call it a genoa sail instead (lol).
You have the new rudder system so weather helm won't be a problem. In winds over ten mph you will likely need to furl the main a couple turns.
What the jibs really help on is the upwind and downwind performance, definitely try those out first. I found my old jib didn't add more than a couple mph on a reach. It's the ability upwind where they really make a big impact.
Good luck
Bob

My first impression is that it's about 25% too large. But the position is probably just right.

I don't think you'll need the sprit unless you go with a spinnaker.

Concentrate on the slot (the opening between the foresail and the mainsail). That area will concentrate wind onto the Leeward side of the main, increasing your mains performance even as the jib helps you point higher. If the jib gets too hot it will backwind the mainsail, ruining its shape.

Downwind, the jib is usually in the shadow of the main, so it may be hard to fill the foresail unless you can really let it travel out, or change your angle to the wind.

Since you can furl both sails, you are now perfectly equipped to experiment with finding the best combination. You better be ready to hike out!

Well done, John. Happy tuning! Wish I could be there with you.

Oh, and can you give us some shots with both sails deployed?

Actually if you can take video some of the expert sailers on here can help make suggestions on what is going on and how to improve. I had an Swedish expert sailer go out with me, he made tons of suggestions and improvements. Actually he is the one who suggested I cut the 40 sq ft jib down to 30 sq ft because the wash from my foresail was deforming the main. He is also the one that told me I had to add a bowsprit to make everything work, he said my slot was too small.
Bob

I've packed it all away as it was getting pretty windy. I did intend to take a photo with both sails out but I was worried that my AI might launch into the neighbours car. I'll have to wait until next weekend before I bring it out again, so I'll take some more photos then.

My original plan was to use this rigging method for the Jib



and have the two rear pulleys on the bow brace cross member (in front of the mast) and cleats on the AKAs



But with the rear of the sail way past this point that won't work. That is why I was thinking of a bowsprite to move the sail forward 300mm.

On another note, hopefully my new trailer will arrive next week so I will from loading chest height


To a nice low one, which will also allow me to work on it without having to unload/load off the high trailer.

Just to try it out I'm sure the two line tack system you show in the top photos will work fine (same setup I used. The auto tacking rig can wait. If it works great, you can take your your time making the bow sprit
Just a thought.
Bob

I still have yet to rig the jib to furl, so I might do that before the first on water test.

Sent from my A500 using Tapatalk

Went out today with the watertribe group (http://www.watertribe.com) up at Ft Desoto/Egmont key, actually had a lot of fun and met up with lots of very nice people. The winds ended up being a little more challenging than we anticipated, here is the history from windfinder

The plan was to launch from Ft Desoto then go to Anna Maria Island for lunch (directly upwind), but it ended up getting to windy and the waves across the cruise ship channel across the Tampa Bay opening got up to 3-4 feet so I believe everyone turned back, all's I know for sure is I got 3/4 of the way there, and decided this was no longer fun so I turned around and went back to Ft Desoto.
With the winds gusting to 27 mph at times it ended up being way to wet and rough for my comfort level. My wing jib handled everything flawlessly, actually I furled up the main completely for a while and just sailed on the wing jib.
On that same run which I have done before in similar winds I really pushed the boat hard in the past, but now I'm a little older and a little wiser so I didn't try to set any speed records this time, actually I had the main furled in 2 turns all day.
The reason I am posting is I have come to the realization that I will likely never use my spinnaker again, so I'm going to remove it from the boat and retire it after 3 1/2 yrs of faithful service. It turns out the wing jib performs so well even on downwind that I get nearly as much performance from the wing as I did from the spinnaker (33 sq ft vs 135 sq ft), top speed today was around 13-14 mph on a downwind (without needing the spinnaker), yea with the spinnaker I could have gone faster, but I deem those speeds to be just too dangerous on a TI, and never push it that hard anymore.
I also learned that once the wind gets above a certain threshold ( I think around 12mph), I can no longer sail faster than the wind upwind, I was able to maintain around 8 mph upwind (about 15-20 points off the wind) but that was it (maxxed out), there appear to be some efficiency loss that I don't fully understand, basically this all means my TI works great in low winds, but performance gains from the wing jib and hybrid power drop off rapidly as the winds and waves get higher.

I covered about 15 miles for the day and had the motor running the entire time (no more than 1/4 throttle, and just idling at times). I measured my fuel used for the day, and I ended up using 1/3 of a gallon ( about $1 dollar in fuel), I had to pedal a little harder than usual but nothing exhausting. I still contend that there really is something unique about the Adventures type boats Tri-power capabilities that Hobie should in my opinion be exploiting more ( ie.... using all power sources at the same time).

Bottom line I doubt I will be taking my boat out anymore is anything over 10-12 mph winds, it's just not as fun for me.
Bob

I managed to get a little free time this afternoon so did a little work on the bow frame and took some photos with both sails up.

Once I rig up a furler on the jib, it will go around 200-300mm higher.





I am going to put a 4mm aluminum plate on the top of the frame that will have the sail attachment point and will also take the bow sprite if I need to have one.



I will glue some high density foam underneath the bottom plate. When I put the top plate on, I might through bolt the top and bottom plate rather than the self tappers I have used here.

John:
The only thing I might have done differently would have been to move that small plate a little further forward, then make a slot in the plate that fits over the lifting cleat. With that the side to side force from the jib would be obsorbed more by the bow brace than the cleat itself. The cleat would still be usable (it would be sticking thru the plate). Alternately since it looks like you already have everything cut and screwed in, would be to add an additional 1/8" x 1 1/2" aluminum piece with a slot in it, that bolts to the underside of the cross brace with flathead screws (just a thought). A simple pin thru the cleat would also help hold the front of the bow brace down. On mine I depend on the attachment at the back (on the AKA bars) then have a small strap that slips over the front of the bow (near the top) to help hold it down. I then used a couple small pieces of spectra string wrapped around the front of the bow (above the water line) to help hold the bow brace down. I don't have anything under the water line. That small grey spectra string that Hobie uses on most of it rudder systems is extremely strong (about 400-500 lbs test), and simply doesn't stretch at all (amazing stuff), I believe most Hobie dealers stock it, over here it's not very expensive either (about $0.22 cents per foot), I use the stuff on everything I can.

I believe the standard Hobie jib is 25 sq ft. The Hobie kayak sails that most guys are using on their AI's are 22 sq ft. So I don't think you are going to be out of the realm with your jib, also with the jib being furlable you can always firl it in a couple turns in higher winds, then let it all the way out when the winds are very light (best of all worlds in my opinion). And better yet the H16 jib is actually designed as a jib, whereas the Hobie kayak sail was never designed to be a used as a jib.
Only one way to find out, get out there and try it all out....
Good luck
Bob

The Wave jib kit is 25 sq ft and the jib on the 16 is closer to 55. And that's still a fraction of the massive 218 sq ft total.

Just eyeballing the different Hobies, it seems to me that an AI or even TI is better suited to adapting a furling jib kit from a Wave or Getaway. (The Island sails appear closest in position, profile and material to the Bravo's).



And after staring at this image for awhile, I get the feeling that grafting an uncut H16 jib on our boats is seriously overcooking the sail plan.



Bob has already pushed the limits and taken things in a new direction with the wing sail, but for John and anyone else trying this, I would advise going small, try to compliment the boom-less design of our mainsail and keep the rigging to a lightweight minimum.

Then, as you test it - furl early, and often.

Bob, Thanks for the advice, I think I can extend my setup so it goes over the bow padeye.

NOHUHU, Trust me, I'm pretty nervous about this sail, which is why I want it furlable before I test it on the water.

I'm hoping to have things ready for a test this coming weekend.