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 Post subject: another boom experiment
PostPosted: Mon May 14, 2018 10:34 am 
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edit.. all the pictures in this thread have probably gone away so I put them all on this page
http://analogengineering.com/sail/hobie ... auler.html

If you have been around this forum for a while, there have been a few boom experiments, here is one that I found from a search

https://www.youtube.com/watch?v=CVrLIBqztsc

Im not sure I think there will be much improvement using a boom for reaching.. but maybe some small incremental amount. My reason for messing with this is that buddies are getting spinnakers and the lake I sail on has a lot of downwind sailing so what drove this is more about down wind sailing.

So the boom for down wind would act more like a whisker pole allowing the main sail to show a lot of area when heading down wind. I have been messing with different versions of barber haulers so had the pulleys at the ama and the cleats for the barber hauler already mounted on the hull. I used this again as a sort of boom vang.

The boom is made from an old top section of a windsurfing mast. I have not tried it yet.. but it looks promising

First picture shows the windsurfing top section mast and all the compents noted.

Note that the barber hauler attached near the boom end is a continuous loop and will act somewhat like a boom vang.

The down side (and I still have not tested it yet), only one person sitting in the back seat can use the boat with the boom.. unless the front person REALLY ducks..

Note.. no new holes were drilled in anything doing this (about the first time that has happened LOL).

Image

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Block attached to the outside of the Ama

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Dont know how this will work yet but I wanted an adjustable outhaul. If I need to reef the sail, the outhaul is easy to disconnect and the boom gets set over to one side - not used when the sail is reefed.

Image

I still want to be able to reef the sail so this is how it will look when the boom is still attached at the front but held over to the side by the barber hauler lines

Image

The tapped holes to mount the plate for the rotating boom front end were already on the front brace so no new holes


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Boom is detached by pushing on the pin and pulling it out. I will bungie this in place later

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Boom stored in the paddle slot - held in place in the rear by the barber hauler lines

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The amas can be folded with the boom in any of the positions it can be placed

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Image


Last edited by walt on Sat Jan 26, 2019 9:03 pm, edited 1 time in total.

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PostPosted: Mon May 14, 2018 3:05 pm 
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Wow Walt, that’s a lot of work for an experiment! 8)
A boom is not on my ‘to do’ list, but I’m interested to know how it compares to the spinnaker.
Please keep us informed of your results.


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PostPosted: Mon May 14, 2018 8:37 pm 
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nice work, Walt. I think about a boom every time I'm heading down wind...


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PostPosted: Tue May 15, 2018 1:33 am 
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Sorry to be brutal Walt, but the thought "ashtray on a motorbike" springs to mind!

The Hobie spinnaker will deliver the performance you are after, without sacrificing the front seat. I have cut a notch in the standard paddle, which catches the second knot on the mainsheet to mainsail hook rope, so if I really have to, I can push the mainsail clew out to level with the ama, giving wing-on-wing performance, but since I got the spinnaker, I haven't bothered.

But please ignore me, as it is always interesting to see someone thinking outside the box

Another performance tweak (which I think fusioneng tried) would be to have the akas bent upwards, so that only one (or even none!) ama is in the water at a time, greatly reducing wetted surface area.

But I think I'm a bit lazy, and tend to think of my TI as a marine SUV rather than a Shelby Cobra :D

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


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PostPosted: Tue May 15, 2018 6:13 am 
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Tony:
Yep I did that, (raised my AMA’s). I did it by just extending the AKA bars about a foot per side. i just cut the aka bars out near the ends, before the curve starts, and added an aluminum extension. I think the AMA’s ended up around 3” higher, they fold in no differently, a when folded in the back of the AMA’s are about even with the rudder, ( the boat on the trailer still fits in the garage, (it’s no longer than before). Widening the boat roughly doubles the flotation on the AMA’s.
If you have just the stock 90 sq ft sail setup, the mod is hardly worthwhile. My TI’s all had much more sail area, (up to 250 sq ft), and my mainsail was raised up, (around 4”-5” to give me more headroom).
Keep in mind my boat was tuned specifically for upwind sailing, (which is 90% of the time around here because of geography). The worst point of sail on my TI’s was a 90% reach, so I avoided that sailing condition like the plague, ( the next sail design will likely be a jointed wing so that should cure that problem. Also while underway, my boat is planing so it’s quite a bit higher in the water, so the AMA’s typically mostly out of the water while underway.
FE


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PostPosted: Tue May 15, 2018 6:53 am 
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I have mixed feelings about any change that gets away from the original easy to rig, easy to use super high wind range of the TI. Plus its fun to go to some destination with other TI's and now with changes like the spinnaker, they dont all perform the same.. Oh well..

Seems two question regarding the boom vs spinnaker. Will the boom/ whisker pole work as well as the spinnaker for the conditions where the spinnaker adds benefit and second, does the boom add any performance benefit outside the range of the spinnaker? Ie, in the conditions where you would normally just use the main sail, does adding the boom have any benefit?

And.. its always hard to tell about a change like this without going through a season of racing. There is no TI racing and I probably would not participate if there was. About the best you can do is side by side sailing with another TI who has everything identical except for one change.. hard for that to happen also. I have never seen any good data taken on a sailing related change here - example in the first video - no wind speed or GPS or wind angle measurements taken.

I can already imagine a new safety risk with the boom caused the by the barber hauler/ vang and sort of traveler "loop" thingy I have have set up. I think it will do good things for sail shape but can imagine it increasing the chance of a capsize if winds came up fast and strong. I will have to watch for that.

Giving up the front seat is a huge negative. But at the same time, I really enjoy sailing the TI solo from the rear seat and think it also makes a nice solo boat. The TI sailed from the rear seat solo is the master at downwind.. During the summer, Im solo most of the time so.. this will be fun to experiment with. And super easy to just not use the boom when my wife is along - just like we have been doing for a few years now.

Could be that I will abandon this because of too much hassle to use - just like I already did with the slotted paddle and two iterations of barber haulers that I have tried.

Hoping to keep this thread about boom vs spinnaker for a while.. Maybe we need a new separate thread for some of the other ideas mentioned?


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PostPosted: Tue May 15, 2018 7:44 am 
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"Ashtray on a motorbike." LOL.

In my estimation, if you're going to improve performance, it starts with stiffening the mast. That boom will do for you about the same thing 12' of line attached to the clew and threaded through leeward ama will.


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PostPosted: Tue May 15, 2018 8:09 am 
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Quote:
That boom will do for you about the same thing 12' of line attached to the clew and threaded through leeward ama will.

thats pretty much what I have already been using for about a year now - it does help with down wind. I think I will get better downwind performance with whisker pole (boom acts like a whisker pole when let way out) and the speculation is that the whisker pole just presents more apparent sail area than you can achieve with what is mentioned above. I use a whisker pole on my seilboat for downwind and apparent sail area does make a difference until you are hitting hull speed. But.. we are all just speculating.. i need to spend some time trying it out.


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PostPosted: Tue May 15, 2018 1:00 pm 
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You are correct about the whisker pole. Anything that contributes more to shaping the sail as opposed to just positioning it, will give better performance, but at what price? If in any given run, nothing will give you 60%, a clew line(?) will give you 80%, a whisker pole 90%, and a boom 95%, then it's just a matter of how much effort you want to put into getting max efficiency, because as efficiency and complexity go up, convenience and ease of use goes down.


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PostPosted: Tue May 15, 2018 8:24 pm 
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A Hoyt boom is darn handy. Its a curved structure that is self-supporting and self vanging. Does not clatter in light air and fully projects the sail when eased. Highly recommended.

https://www.google.com.pr/search?q=esca ... bGZLfosYnM:


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PostPosted: Tue May 15, 2018 8:57 pm 
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When I don’t have my spinnaker along, ( I don’t use it very often anymore, and typically leave it down, or leave it at home).
I do always have my jib though, on downwind I typically put the jib to one side and the main to the other on a direct downwind, ( wing on wing), however this is still a little slow, even with a barbor hauler.

I can actually go faster jibing back and forth on downwind and avoiding sailing direct downwind.
That’s just the way my boat works. I have both barbor haulers, and a slotted paddle, but seldom use either. Instead I tend to sail downwind with the wind around 30 degrees off the stern.
FE


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PostPosted: Wed May 16, 2018 1:55 pm 
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bluelaser2 wrote:
A Hoyt boom is darn handy. Its a curved structure that is self-supporting and self vanging. Does not clatter in light air and fully projects the sail when eased. Highly recommended.
https://www.google.com.pr/search?q=esca ... bGZLfosYnM:
I like the shape of that Hoyt boom. It might be interesting to fabricate something like that to fit a TI as an experiment. This is quite an interesting thread. Spinnaker vs Boom. You just need to make the boom easy to install and remove so you can furl the mainsail.

Jim


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PostPosted: Wed May 16, 2018 4:43 pm 
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Cap'n (lol), given that the spinnaker around doubles the sail area, no boom addition is going to provide as much extra propulsion. I also reckon the satisfaction of managing two sails (especially on a downwind reach) makes up for the potential for screw-ups!

PS. If you were to expand on your offer to host images, there is a potential for you to become extremely popular, in the wake of Photobucket's suicidal move. :D :D

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2012 Tandem Island "SIC EM" with Hobie spinnaker


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PostPosted: Wed May 16, 2018 5:23 pm 
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tonystott wrote:
Cap'n (lol), given that the spinnaker around doubles the sail area, no boom addition is going to provide as much extra propulsion. I also reckon the satisfaction of managing two sails (especially on a downwind reach) makes up for the potential for screw-ups!
PS. If you were to expand on your offer to host images, there is a potential for you to become extremely popular, in the wake of Photobucket's suicidal move. :D :D

Tony, I enjoy playing around with my Hobie and fabricating is a challenge. Especially if I can do it with materials I have in my garage lol. A good boom might be an alternative (not in addition) to the spinnaker which isn't for everyone. Someone on this forum many years ago was experimenting with flexible booms. I want to say it was DogsLife but can't remember.
Jim


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PostPosted: Wed May 16, 2018 7:13 pm 
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Took the TI out with the boom today and think it took the performance up a notch everywhere except for pinching very high into the wind. If you have the sail sheeted hard to center the boom doesnt make much difference as the pull from the sheet is in the same direction as the pull from the aft end of the boom.

But as soon as you start to let the sheet out, the boom gives better shape. That vang setup was a little bit of a pain in the ass to use but it did great things for adjusting the sail twist. Bonus for the vang set up.. It also makes a great preventer for down wind.

Worked flawlessy exceot about half way through the session the hose clamp for the vang setup slipped down to the bottom end of the boom so I sailed the rest of the day without it.

No other TI's around but a bunch of under 26 ft keel boats out racing. I spent a lot of time exceeding their huill speed.. so I had some fun. Many times I was up the 8 mph range, my peak speed today was just under 11 mph. This is from watching the chart plotter that I have mounted just behind the front seat.

Captian Chaos, you are correct, you need to be able to disconnect the boom easilly. At the end of the day I had to do this to furl the main and found that I tightened the main sheet and headed staight into the wind, it wasnt that hard.

Note also in these pictures.. I have a great forward view, no foresail creating a large blind spot right in the direction you are traveling.

Picture below down wind

Image

Image

Image


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