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The ultimate Tandem Island (hydrofoils, Spinnaker, jib, etc)
http://www.hobie.com/forums/viewtopic.php?f=69&t=33720		 Page 11 of 35
Author:  DM06 [ Thu Oct 03, 2013 10:24 am ]
Post subject:  Re: The ultimate Tandem Island (hydrofoils, Spinnaker, jib,
I'm sailing the same conditions here in the San Antonio area. Winds are usually 5-10. I have a Nacra 5.0 that I used to sail on Lake Michigan. I miss the challenge of having 2 sails to tweak. The TI, while versatile, is lacking in the sail tweaking department. While I don't pedal unless I have to, I find that (moreso with two on board) I cannot get very close to the wind. It seems like the sweet spot is 45 degrees if not more. Actually probably more...

However, the wife hates the Nacra due to the mast stepping and launching procedures. Lets face it. I'm out sailing within 10 minutes with the TI. Near the end of the sailing season in Chicago, when we finally had a rhythm going, it still took us at least 30 minutes to get the Nacra ready.

I'm just getting bored, and frustrated waiting for hobie. They are a riddle to me. They seem to really take care of their customers and listen to them, but at the same time, we still don't have a Venturi style scupper drain to keep our butts drier, and we don't have a jib. Two things that people are constantly asking about.

I would very much like to dive in and make your bowsprit, mast head, and try utilizing a spare Nacra jib, but 1) I really don't want to do any drilling into the hull and 2) I'm a picture guy. I need pictures and measurements and pictures and lists and pictures. Many folks have awesome ideas which they describe in great detail using multiple paragraphs, but that just goes in one ear and out the other.

I've been following your progress, and trying to save the pictures you post along with the relevant text in Evernote, for the day I decide to pull the trigger and start building. Right now what holds me back is a lack of an understanding on how to do the bowsprit without drilling any holes. In a perfect world I'd rather make an inner brace to strengthen the bow instead of using a bunch of epoxy, but I don't have the knowhow, or the tools to create such a beast.

I'm so close to pulling the trigger though. Like, gauging what the wife would say, close.
Author:  NOHUHU [ Thu Oct 03, 2013 3:22 pm ]
Post subject:  Re: The ultimate Tandem Island (hydrofoils, Spinnaker, jib,
I feel ya DM. Been sailing the Nacra 5.2 and H16 and love the furling jib setups (self tacking would be even better).

Your sail would be more of a gennaker once installed. That design would be more usable on our boats, I think. There are a couple considerations.

First- we do not have the typical bridle setup, and there's no good way to add one. Next - there is a massive amount of mast bend on the TI (and some breaks I hear). Adding a removable backstay and permanent internal backing plates would be the way to go. It can be done, but Hobie's mast top does not make it easy.

Aesthetically, you also have to consider if you want to put cloth sails on the plastic boat. Maybe for testing. Plus the furling units are uber expensive.

Finally -No matter how you rig it, I believe you are going to need Hakas to sail it properly. May as well go ahead and make those. :mrgreen:

So those are the challenges.

I too am pretty tired of waiting for Hobie to come up with a solution kit for this. The only positive sign is that a Hobie engineer flew a spinnaker in the Everglades Challenge this year and aced the race.

No word on when the company will make this available to his competition. :wink:
Author:  DM06 [ Thu Oct 03, 2013 4:36 pm ]
Post subject:  Re: The ultimate Tandem Island (hydrofoils, Spinnaker, jib,
Does the 5.2 rig the same? My 5.0 jib leading edge has clips that clip to the forstay, and an up haul? I'm rusty on my terminology. Would it be difficult to rig the same on the TI? Are the masts breaking even with fore and aft stays?
Author:  NOHUHU [ Thu Oct 03, 2013 10:37 pm ]
Post subject:  Re: The ultimate Tandem Island (hydrofoils, Spinnaker, jib,
Similar, but I think you have a spreader bar at the base, between the hulls. If you have a roller-furling version it probably looks like this: :mrgreen:

Image

On the Hobie, you'll need to safely attach the jib halyard, and a backstay to the TOP of the TI mast. Not many folks have accomplished this mod and fusion is your best source of picts. I'm reluctant to do it myself.

All the breaks I am aware of effected stock sails and masts.
Author:  tonystott [ Fri Oct 04, 2013 12:00 am ]
Post subject:  Re: The ultimate Tandem Island (hydrofoils, Spinnaker, jib,
Nohuhu, could you please post a photo of the roller furling? :lol:
Author:  NOHUHU [ Fri Oct 04, 2013 12:59 am ]
Post subject:  Re: The ultimate Tandem Island (hydrofoils, Spinnaker, jib,
3rd one from the right, Tony.
Author:  fusioneng [ Fri Oct 04, 2013 5:13 am ]
Post subject:  Re: The ultimate Tandem Island (hydrofoils, Spinnaker, jib,
Can you send a closer pic. This time without the stupid boat. Lol
Author:  DM06 [ Fri Oct 04, 2013 6:25 am ]
Post subject:  Re: The ultimate Tandem Island (hydrofoils, Spinnaker, jib,
Lol. The 5.0 has two fore stays that come together at a long fitting with a handful of holes. The forestry from the mast then attaches to that and, depending on which hole you pin it to, allows adjustment of the rake of the mast (I'm assuming).

I have to be extra careful (besides injury factor). If the mast brakes, especially with the wife on board, her stock in the hobie would go way down. Right now she actually likes it. And the more "Household 6" likes it the more I get to sail.
Author:  DM06 [ Sun Oct 06, 2013 12:19 pm ]
Post subject:  Re: The ultimate Tandem Island (hydrofoils, Spinnaker, jib,
Fusion, are there pics of your bowsprit buried in this thread somewhere?
Author:  fusioneng [ Sun Oct 06, 2013 4:01 pm ]
Post subject:  Re: The ultimate Tandem Island (hydrofoils, Spinnaker, jib,
DM06 :
I described and posted photos of pretty much everything earlier in this thread, and in some other threads (hard to keep track).
I just went out to the garage a snapped a few shots, hope they help.

Here are a couple shots of the bow sprit itself. The black nylon lift strap sewn into a sling shape (very strong ~1600 lbs break strength) and the spectra string (each spectra string is around 300 lbs test) is what holds it down.
Image

Here is another view

Image

Here is how the 3/4 sq aluminum channel is bolted to to the front of the aka cross bar. I just bent some 1/8 x 1/2 aluminum around the aka brace, and bolted it to the 3/4 sq tubing (1/16 wall thickness)
Image

Here is an older pic of the bow sprit with the sails and furlers on it.
Image

Hope this helps
Bob
Author:  DM06 [ Sun Oct 06, 2013 6:40 pm ]
Post subject:  Re: The ultimate Tandem Island (hydrofoils, Spinnaker, jib,
That certainly does help, thank you. Few questions, and I'm sorry if you've answered me till you're blue in the face, but what is the thinner black line going up and around the bow? It looks to be attached to a bolt fastened through the hull?

And secondly, it looks like a lot of it was un-formed, un-re-formed? Metal, but you've got some bends in there that make me wonder if you access to a metal shop.

Makes me wish I hadn't left my aviation maintenance career. Could have used the metal shop or made some crazy strong carbon fiber/Kevlar/ honey comb madness.

I am researching the crap out of the forum but there's a lot of info there so it's slow going.
Author:  fusioneng [ Sun Oct 06, 2013 8:11 pm ]
Post subject:  Re: The ultimate Tandem Island (hydrofoils, Spinnaker, jib,
DM06:
There is nothing attached to the hull or no modifications to the boat at all on any of my stuff. That little string going over the top with a bolt on it is a shoe lace with the safety pin for the trailer hitch (so I don't lose it). The big black cable is the trailer lights cable just draped over the bow sprit. The yellow blob on the front of the bow (above the nylon strap on the front) is hot glue melted onto the front of the bow from a hot glue gun. It is just on the surface and can easily be cut off if I ever sell the boat. That blob is what holds the strap from pulling up. The bow sprit itself is a fiberglass ax handle from Home depot with the yellow polypropylene plastic peeled off. It's a fiberglass pulltrusion 3/4" x 1" x 3 ft long. It is extremely strong and very light. You can put a brick under each end and a 250 lb guy can jump up and down in the middle all day long (I designed it many years ago and we used to do that in the factory where we made them just for something to do). I always lift and drag the boat around by the bow sprit because it's handy, I have stood out on it trying to untangle sails a few times out on the water as well, so it is probably 4 times stronger than it needs to be.
The 2 ft long piece of 1/8" x 2" aluminum has about ten 8/32 flat head screws holding the pultrusion down with drilled and tapped holes into the pultrusion on the bottom. The 1/8" x 2" piece of aluminum at the back was just bent over hull by hand so it was close. I then filled underneath it with bondo (fiberglass body putty, ( easy to work with and inexpensive at walmart)) so it fits over and conforms to the hull perfectly.
There is an oval slot in the middle of the 1/8" x 2" x 2ft that fits over the cleat on the bow of the boat, this prevents side to side motion. I suppose if you wanted to you could slide an aluminum pin through the front cleat to help hold it down (I did that on the original design, but I lost the aluminum pin about 3 yrs ago, and never replaced it). Aluminum is very easy to work with and you can bend it all with your fingers. My only tools are a hack saw and an electric drill. The whole thing only weighs about 2-3 lbs.
All my furlers are just simple PVC tubing with string wrapped around them they cost about 2 bucks to make.
Hope this helps
Bob
Author:  Chopcat [ Mon Oct 07, 2013 12:10 am ]
Post subject:  Re: The ultimate Tandem Island (hydrofoils, Spinnaker, jib,
Bob

I have got myself a jib and the guys at Aeroluff http://www.aeroluffspars.co.uk/spars are going to add one of their roller/reefing spars.

I was chatting with some crusty sea sage yesterday whilst he was looking at the Ti who was telling me that what i needed to do was to triangulate the mast head. ie: run wires almost at 90 degrees to port & starboard (see I'm catching the sailing lingo) but slightly aft. what do you think.

I suspect that might work fine if you have a relatively stiff mast like the cats but for a floppy :lol: one like ours maybe not.

CC
Author:  DM06 [ Mon Oct 07, 2013 5:42 am ]
Post subject:  Re: The ultimate Tandem Island (hydrofoils, Spinnaker, jib,
If my memory doesn't fail me, I believe one of the folks here who added a jib did front and side stays but ended up abandoning the design. Don't remember why.
Author:  fusioneng [ Mon Oct 07, 2013 10:19 am ]
Post subject:  Re: The ultimate Tandem Island (hydrofoils, Spinnaker, jib,
Chopcat :
I don't recommend adding side stays, you won't need them, the mast system is plenty strong side to side, plus the mast is designed to bend a couple feet to spill excess air when sailing in higher winds, the stays would prevent that (not good). Of course I tried that early on and it makes capsize much more likely in higher winds, and also you have a boomless square top sail that's designed for this type of flexible mast, adding side stays ruins the sails performance, if you had a bermuda type sail with a boom it might be different.
The weakness in Hobies mast design is the small 1/4 stud at the base of the mast holder cup. Excess forward or rearward force from the sails will break that stud. A strong downwind is what would break that stud, and if you have a jib, you almost have to have the rear stay to protect that stud from too much fore/aft force, especially on a downwind in higher winds with a batwing configuration (one sail on each side).
The rear stay doesn't interfere with the mainsails performance, it just prevents the mast from bending two far forward at the top, which makes you jib bow out (like a U shape) and become too loose to work. I use flexible nylon rope so it stretches under load, and takes up some but not all of the strain. When on a reach the rear stay line is actually very loose and sloppy (don't need it). Actually if have just a jib and don't bother with a jib/spinnaker combo, you might be able to forego the rear stay line, but be very careful not to strain the mast too much on your downwinds.
CaptChaos is using a standard 22 sq ft kayak sail on his Adventure Island (which is the perfect size for that boat), and he doesn't have a rear stay. The AI's mainsail is mounted much further back on the hull so an extended bowsprit in not really needed. But on the TI you will notice that the mainsail is way forward on the boat, and the angle on your jib or spinnaker is not enough to lift the bow out of the water without the bowsprit, plus you can't get enough air in between the sails. On my TI before adding the bowsprit my bow would submerge underwater with both the mainsail and my old 35 sq ft jib deployed on a reach (and downwind). Increasing the angle of the jib creates enough lift to raise the bow out of the water (important if you ever want to see any speed, and stay dry). With the bow out of the water the boat actually planes (kind of, the rear still drags too much because it's pointed).
Hope this helps
Bob
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