The Spinnaker Mast Topper was never Flawed

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I would not at all assume this is true. A displacement hull like we are used to thinking about (mono hull sailboat) generally can only go a few percent over its theoretical hull speed.

The TI is 18 foot long and has a theoretical hull speed of 5.68 knots. Yet its common to get these over 10 knots. That is 76 percent over theoretical hull speed. That does not at all fit with the conventional displacement hull model.

Walt you are correct. You can exceed hull speed but the horsepower requirements go up exponentially. But there are exceptions.
For any cat hull with a length to width ratio of over 16/1, hull speed doesn't apply at all (this is why cat hulls and surfski hulls are very narrow) no speed limit.
The other magic number is 8/1 length to width ratio, as in most high end sea kayaks. The hull now becomes what they call a modified displacement hull, and they can go faster (the TI L/W ratio is 8/1).
Any boat if you can get it on top of the water and you have enough surface area and horsepower it will plane, a good example is a John boat.
The TI planes, but that pointed back end creates a lot of drag, it's actually pretty easy to convert the back of the hull to a planing type hull, with add on hull mods.
FE

Or.. you created more wetted surface area and increased wetted surface area drag at all speeds possibly making the boat slower. I think there would neen to be a racing fleet of these with results over a season to see if some sort of modification to the rear of the hull made any difference. I suspect that it doesnt make any difference but that is just my opinion. Ive watched this forum for a while and have neverr seen any actual measured evidence (with good scientific method) that modifying the TI hull has any benefit.

Before I modded the Triak floats to double their volume, I considered adding wider flat bottomed floats and a new set of akas so that a planing surface was created aft of the driver to get his ass out of the water so the boat could go faster. I decided that was too much work and I'd not be able to paddle very easily. I like getting in and out of the water quickly and don't really care how fast I go as long as I can get somewhere and come back in a couple hours. If I want speed, I have the Hobie Getaway or my neighbor's Windrider 17 or my friend's Weta. Truthfully, the Triak with the bigger floats isn't that much slower--top end of 11 whereas the Getaway top end is around 15. Completely different rides, though.

You are right, I misspoke, the displacement hulls aren't what's keeping the boat from going faster than 11 (as FE pointed out), I need more horsepower to go faster. But (as you folks who have added jibs have found out) the boat will still top out somewhere no matter how much sail you add to it (heck, even AC72s have a top end), just gotta be satisfied with what you got. It is what it is.

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R/Thom
SeaRail 19
Triak
BMW C600
Formerly Getaway with Custom Spinnakers
Formerly raced F24 Mk II

I think that class racing AI's would be interesting: a merger of sailing skills, strategic skills, and athletic ability (Mirage Drive).

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2015 AI in "Dune" - "The Grey Pig"
2017 Trailex 450 Trailer
Pre-September 2015 cradles
(anybody want to buy a slightly-used AI SpinKit?)
eMail: [email protected]

I don't think I would be allowed to compete, because I always cheat by any means possible.
Like I keep sayin, I'll never be a real sailer.
FE

You and I would have secret outboards on the boats (I like having an outboard...part of the plan when I bought this boat).

I may have to get the spinnaker kit but it will mostly be because I need it to sail with friends who have these boats and the spinnaker. I did not buy the TI as a performance sailboat, I bought it because it is very easy to setup and has a huge easy to use wind range and its good for going places rather than just sailing because of the mirage drive. The spinnaker might be somewhat fun but it somewhat takes away from the simple setup that I like so much. I have mixed feelings about it..

What I would almost rather see is maybe the same hull and ama's ect but an option to put whole different rig on it. Maybe a stayed rotating carbon wing mast/ soft sail plus jib. The bendy mast and easy to furl sail work just fine with the original design but I think its a compromise when you start to try and add performance. So maybe the same hull but two completely separate rigs each optimized for what you are trying to accomplish.

They had a ai fleet in Alameda racing for a while. They restricted pedaling to just while tacking. The five entries became 4, then 3...

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R/Thom
SeaRail 19
Triak
BMW C600
Formerly Getaway with Custom Spinnakers
Formerly raced F24 Mk II

Walt, sadly, if there was enough demand for aftermarket performance sails etc, someone would already be offering it, but clearly not...

As for racing, the elephant in the room is the Miragedrive. Stick an Olympic cyclist in the seat, and that AI is going to win unless major navigational errors are made, on the other hand, restrict pedaling, and then diehard Island fans will lose interest. I just can't see fleet racing taking off for Islands (and of course, even less so for Islands sporting specialist rigs).

Thank goodness these things are so versatile that racing doesn't need to be on the agenda. (but the Hobie spinkit is well worth it, trust me on this lol)

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Tony Stott
2012 Tandem Island "SIC EM" with Hobie spinnaker

This original post was about the batten being set too tight and I think that will end up being useful to me.. The thread has gone a little off topic so hope this question is OK here..

You guys are convincing me that I probably need the spin kit.. One question I have regarding putting this on a TI is likely in a discussion somewhere but I will go ahead and ask here.. Some people like to sail the TI solo from the front, some from the rear. Both are good and have their benefits and this has been discussed many times in the past. I just happen to like the rear and have modified the controls (like the sail reefing) to the rear.

With the spin kit.. is the setup optimized for one of the two positions (front or rear) or can you set it up so that its easy to control from either seat?

And.. maybe one more question.. how much time does the spin kit add to your setup and take down time?

As far as I can see, you could operate the spinnaker from the rear seat provided you don't have the too-short halyard/backstay shipped out initially. I believe Hobie is onto this and is automatically sending out the longer line.

To raise the spinnaker, you would pull on the line coming from the cleat on the front crossbar; to snuff the spinnaker, you would pull on the line coming out the back of the snuffer bag.

The sheets would each terminate at the swivel cleat at the inner end of the rear crossbar. You would be able to work these from the rear seat.

Set-up time will vary hugely depending whether you dismantle it for car topping, or else put on the trailer.

In my case, as I use a trailer. Extra set-up time and effort is minimal. After returning to shore, I lower the mast and put the topper in the rear seating area, loosely bundling the halyard/backstay there too. As I fold in the amas, I place the snuffer into the front cockpit along with the Miragedrive. Spinnaker sheets get loosely coiled and dropped into the rear cockpit too (I usually have the well filled with the stopper) That's it for the spinnaker!

When I arrive at the ramp, I attach the topper to the mast, making sure that the halyard/backstay is free to allow the mast to go up with no restriction (actually, I cheat a little bit here, and add a temporary extension to ensure there is no downward pressure on the mast while I am lifting it up into its mount at the front crossbar).

Quick summary, everything but the masthead topper remains connected whether sailing or travelling....

I have no experience car-topping, and procedure would be different if you remove the akas and amas. Maybe others can chime in here

PS. Little tip: I added a "top hat" button on the front face of the forward aka, so the mouth of the snuffer cannot slide inwards on the aka when I am trying to pull the sail into the snuffer. I suspect this will become less necessary as the reinforcing patches at each grommet get more flexible.

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Tony Stott
2012 Tandem Island "SIC EM" with Hobie spinnaker

I trailer my AI and leave it all in place like Tony. I bet it only adds 2 maybe 3 minutes max to your set up time once you have you have done it a few times.

I use to car top prior to this year. The spin setup is a bigger issue for car toppers because most car toppers remove the amas. This would be an issue with the chute and halyard attached. I'm sure it could be done, just more hassle.

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Greg

2016 AI - Spinn & Jib

“Out of sight of land the sailor feels safe. It is the beach that worries him.”
– Charles G. Davis

Thanks! I normally trailer. It also sounds like you can also easily collapse either ama with the Spinnaker kit installed. Two places I launch at require me to use a guest dock - not a problem if you can collapse an ama..

I am currently deciding whether to purchase the spinnaker kit or not. I have read with interest all coments on the kit and the only concern I have is the extra time in rigging as I do assemble my boat at the waters edge, as I carry it on a modified box trailer. I would be keen to hear comments on the additional assembly time with the spinnaker kit only, as I am quite happy with my current mode mode of transport.

Do you remove the akas from the hull? If you don't, you will be able to leave ALL lines still attached. In that case, the only tasks you will need to do to set up are:-
* Move the snuffer from the cockpit to the aka, and do up the two straps to secure it.
* Place the topper on the mast

That's all! Everything else is what you woulds do without a spinnaker.

If you start with the hull and akas separate:-
* Thread the spinnaker sheets through the swivel blocks on the akas
* Move the snuffer from the cockpit to the aka, and do up the two straps to secure it.
* Place the topper on the mast

I am not kidding, these are the only extra steps, once you have done the initial installation as per the instruction video.

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Tony Stott
2012 Tandem Island "SIC EM" with Hobie spinnaker