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PostPosted: Wed Sep 13, 2017 8:09 am 
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Tom Kirkman wrote:
Unlike a catamaran, trimarans tend to automatically turtle as soon as they capsize. The addition of a mast float, unless it is a very large one, won't stop this from happening. And at some point, the addition of such a large mast float does two things - makes it much harder to step the mast, and increases windage which can itself make a capsize more likely.


Ahh I see.... And you know this for a fact?
Well as I guess you have not tried this out yourself or even seen it be done with a TI/AI I might as well get the FACTS right and give it a try.
Seeing is believing mate!

All the best!
/Gustav

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PostPosted: Wed Sep 13, 2017 9:21 am 
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Tom Kirkman wrote:
Unlike a catamaran, trimarans tend to automatically turtle as soon as they capsize. The addition of a mast float, unless it is a very large one, won't stop this from happening. And at some point, the addition of such a large mast float does two things - makes it much harder to step the mast, and increases windage which can itself make a capsize more likely.


He is using an inflatable, so windage shouldn't be a problem. He is also using 40 liters which is almost 90lbs!! displaced. I would think that would be plenty enough.

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PostPosted: Wed Sep 13, 2017 12:00 pm 
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Husse0416 wrote:
Tom Kirkman wrote:
Unlike a catamaran, trimarans tend to automatically turtle as soon as they capsize. The addition of a mast float, unless it is a very large one, won't stop this from happening. And at some point, the addition of such a large mast float does two things - makes it much harder to step the mast, and increases windage which can itself make a capsize more likely.


Ahh I see.... And you know this for a fact?
Well as I guess you have not tried this out yourself or even seen it be done with a TI/AI I might as well get the FACTS right and give it a try.
Seeing is believing mate!

All the best!
/Gustav


Yes, I know this for a fact. I've sail a few trimarans, at least a few times...

An inflatable model would eliminate the windage problem, but it won't stop the boat from turtling unless it's a fairly large float.


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PostPosted: Wed Sep 13, 2017 12:01 pm 
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Tom Kirkman wrote:
Husse0416 wrote:
Tom Kirkman wrote:
Unlike a catamaran, trimarans tend to automatically turtle as soon as they capsize. The addition of a mast float, unless it is a very large one, won't stop this from happening. And at some point, the addition of such a large mast float does two things - makes it much harder to step the mast, and increases windage which can itself make a capsize more likely.


Ahh I see.... And you know this for a fact?
Well as I guess you have not tried this out yourself or even seen it be done with a TI/AI I might as well get the FACTS right and give it a try.
Seeing is believing mate!

All the best!
/Gustav


You're right, I don't know anything about trimarans...


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PostPosted: Wed Sep 13, 2017 12:11 pm 
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Tom Kirkman wrote:
Husse0416 wrote:
Tom Kirkman wrote:
Unlike a catamaran, trimarans tend to automatically turtle as soon as they capsize. The addition of a mast float, unless it is a very large one, won't stop this from happening. And at some point, the addition of such a large mast float does two things - makes it much harder to step the mast, and increases windage which can itself make a capsize more likely.


Ahh I see.... And you know this for a fact?
Well as I guess you have not tried this out yourself or even seen it be done with a TI/AI I might as well get the FACTS right and give it a try.
Seeing is believing mate!

All the best!
/Gustav


Yes, I know this for a fact. I've sail a few trimarans, at least a few times...

An inflatable model would eliminate the windage problem, but it won't stop the boat from turtling unless it's a fairly large float.



Are you up for a bet?? Bet you $100 it will work!!
Its a safe bet mate, I mean you have got the "FACTS"!
LOL

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PostPosted: Thu Sep 14, 2017 8:02 am 
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As a matter of fact, I do have experience with exactly this sort of thing. You're going to run into the same problems as the rest of us did. The weight of such a large float (still has weight even when not deployed) makes the mast harder to step and increases the leverage the mast will have over the boat. You will also have to devise a means of keeping the float from deploying in anything short of a capsize. Rain, humidity and splash, etc. can cause a false deployment. Some have attempted to get around this by the use of the same chemical/mechanism found in inflatable PFD's. The device isn't likely to be able to fit inside the mast, and if attached to the exterior will add to the windage at the top of the mast, and again, increase the leverage the mast has on the boat.

But by all means, give it a try. Maybe you'll be the guy to perfect it.


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PostPosted: Thu Sep 14, 2017 9:03 am 
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I dont know about a catamaran but Ive capsized a 15 foot monohull with and without a float at the top of the mast and also did some experimenting with my old 2010 AI with it flipped on its side in shallow water and the AI (tri) is definitely way more likely and faster to go turtle than the mono hull. The AI is of course also way less likely to capsize in the first place.

When I had the AI over on its side, I had experimented with the amount of flotation required to keep the top of the mast near the water surface and the AI required considerably more flotation than the equivalent sized mono hull (a C15 in this case which is considerably heavier overall compared to the AI).

Thanks to our favorite picture hosting company, I cant show the pictures any longer or how much flotation it took but I think it was on the order 1 to 2 gallons of displacement. Cant exactly remember the detail but Im fairly sure it was 2 gallons or less. 2 gallons is close to 7.5 liter and even though the TI is heavier, I would "bet" that 40 liters would keep the TI mast from sinking (and the boat from going turtle). Who knows with a heavily modified TI but it would seem that you have some margin to work with.

I abandoned the mast float after seeing how "fricken large" it would need to be but maybe the self inflating one might work..

FYI, I have a modified keep out setup on my TI and it has kept me from turtle when a pin sheered. I sail from the rear seat and think that also is nearly pitch pole proof. So.. I think I completely solved my problem with just the keep out lines.


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PostPosted: Thu Sep 14, 2017 9:23 am 
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Tom Kirkman wrote:
As a matter of fact, I do have experience with exactly this sort of thing. You're going to run into the same problems as the rest of us did. The weight of such a large float (still has weight even when not deployed) makes the mast harder to step and increases the leverage the mast will have over the boat. You will also have to devise a means of keeping the float from deploying in anything short of a capsize. Rain, humidity and splash, etc. can cause a false deployment. Some have attempted to get around this by the use of the same chemical/mechanism found in inflatable PFD's. The device isn't likely to be able to fit inside the mast, and if attached to the exterior will add to the windage at the top of the mast, and again, increase the leverage the mast has on the boat.

But by all means, give it a try. Maybe you'll be the guy to perfect it.


Maybe you did not read the entire thread? If not I advise you to do so. I will not repeat myself.
But....
You did not aswer my question mate.... are you up for a bet!? Please .... humor me!
Are you prepare to put your money and pride on the line mate?
You seem to have it all figured out so why not take the chance and earn a few bucks?
Or is your mouth bigger then your pockets?
:lol:
Amazing .... so much negativity!
Well anyway you are really giving me and my pals a good laugh here in Sweden .... but thats about it...
:mrgreen:

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PostPosted: Thu Sep 14, 2017 9:49 am 
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walt wrote:
I dont know about a catamaran but Ive capsized a 15 foot monohull with and without a float at the top of the mast and also did some experimenting with my old 2010 AI with it flipped on its side in shallow water and the AI (tri) is definitely way more likely and faster to go turtle than the mono hull. The AI is of course also way less likely to capsize in the first place.

When I had the AI over on its side, I had experimented with the amount of flotation required to keep the top of the mast near the water surface and the AI required considerably more flotation than the equivalent sized mono hull (a C15 in this case which is considerably heavier overall compared to the AI).

Thanks to our favorite picture hosting company, I cant show the pictures any longer or how much flotation it took but I think it was on the order 1 to 2 gallons of displacement. Cant exactly remember the detail but Im fairly sure it was 2 gallons or less. 2 gallons is close to 7.5 liter and even though the TI is heavier, I would "bet" that 40 liters would keep the TI mast from sinking (and the boat from going turtle). Who knows with a heavily modified TI but it would seem that you have some margin to work with.

I abandoned the mast float after seeing how "fricken large" it would need to be but maybe the self inflating one might work..

FYI, I have a modified keep out setup on my TI and it has kept me from turtle when a pin sheered. I sail from the rear seat and think that also is nearly pitch pole proof. So.. I think I completely solved my problem with just the keep out lines.


Thanks a million for the solid information Walt!
Sounds very encouraging!
:)
I figured 20 liters (~5 gallons) would be enough for a stock unloaded TI but with my heavy "iron barge" I ordered the 40 liter version to be on the safe side (it only weighs 300 grams more). I cant imagine that it would take more then that to keep the masttip afloat in the surface but who knows?? I cant be certain until I try this out.
It will be interesting to se see if the automatic valve on the float deploys fast enough to keep the TI from quick going "full turtle" and if it does will the float raise the masttip up to the surface again from the full inverted "turtle mode"? If is is fully inverted I think it will need a little help to get started, so by pressing down on one ama giving the inverted TI a little tilt maybe the 40 liters (40kgs) of lift will be enough to lift the masttip up to the surface again?

Very exciting stuff! Will it work? :shock:

There seems to be a lot of firm opinions on the forum about the matter but all seem to be assumtions, hearsay and all the negativity sort of bugs me!
Progress is made by trial and error... not negative thinking!
Off course I really want this to work, but I also want us all to get a little wiser and learn a thing or two.
If it would fail at least we all learned something, if it works.... partytime! The beers are on me... or maybe on Tim?
I better try my wetsuit on... I have been gaining weight lately. A cold september-swim i a Swedish lake will do me good... and give you all a good laugh!
They shipped the float from Germany yesterday so I should have it here in a week or so.
Dont You just love Ebay?!
All the best!
/Gustav

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PostPosted: Thu Sep 14, 2017 10:14 am 
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I didn't offer an opinion.


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PostPosted: Thu Sep 14, 2017 10:47 am 
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Well.. I went to that POS picture posting web site and was able to dowload a picture I had there. I put the picture on a fb page so it will go away in a few weeks..

My test is not exactly what I thought it was. Remembering back a lot of years, I just could not get the AI over on its side with the Amas extended so just did the this test with one ama collapsed. The boat is completely floating in the picture.

If the the Ama's were both out all the way, I think considerable additional flotation at the end of the mast would be required over what is in the picture. I have done the same sort of test with a monohul and it definitely takes more flotation with the trimaran even with the ama collapsed on the tri. The test I did was enough to convince me that I no longer wanted to pursue this option and spent the time on keeping the amas from collapsing in the first place.

Give it a try.. I think you will need two people to get the TI over. One person pullling a rope tied to the top of the mast and a second person holding the Ama stationary that will end up floating the boat. I think it will require a lot of floatation and hopefully we get to find out if 40 liters is enough. I would guess so.. but am not at all confident enough to place any bets.

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PostPosted: Thu Sep 14, 2017 11:03 am 
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Tom Kirkman wrote:
I didn't offer an opinion.


No thats true Tom, you did not offer it, you just freely expressed it. Fine with me off course but dont expect to be unopposed as long as I have another opinion.
:D
Its all just a fair and healthy debate and that is just want I want!
No takers on the bet huh??

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PostPosted: Thu Sep 14, 2017 11:16 am 
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walt wrote:
Well.. I went to that POS picture posting web site and was able to dowload a picture I had there. I put the picture on a fb page so it will go away in a few weeks..

My test is not exactly what I thought it was. Remembering back a lot of years, I just could not get the AI over on its side with the Amas extended so just did the this test with one ama collapsed. The boat is completely floating in the picture.
-SNIPPED-


Great pic Walt! Wow it really floats high! That really is very good news!
Well I have been thinking about the effect of the submerged extended ama under the yak.... I was thinking that the angle will maybe change a bit and tent to push over the TI in "turtle mode" but really it should not matter that mutch. Your ama in the pic is almost fully submerged so the lifting/floating force will still be about the same. As long as the akas dont bend (a bit worried about that) and keeps the ama in place straight under the main hull it should balance the yak in aproximately the same way.
Sounds logical to me but I am not the sharpest blade in the cuttlery! :lol:

PS
Yup! I called in some buddies to help me to flip the TI and record the video.
I think I will try to weight down the ama until its submerged to help flip the TI without folding the akas.
An anchor to stabilise the mail hull and keep it in place and a rope in the mast and then pull it over. Once it is healing over I will cut the weights on the submerged ama. Could work...

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PostPosted: Thu Sep 14, 2017 11:35 am 
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Gustav, the spinnaker mast hrad sits on top if the mast but is not attached to it. It's possible that any float attached it it may come off if deployed. You'll probably néed to attach it to the mast itself.

Indefense of Tom. He has been on this forum of years and he's not the argumentative type. I am sure he was just trying to help. He's also a VERY sharp guy with fantastic ideas and a great deal of sailing experience. He is being modest. When he seeks up, it gets my attention for sure.

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PostPosted: Thu Sep 14, 2017 12:05 pm 
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The inflatable float will probably need to attach near the mast.

The sail will likely be unfurled if you ever need that mast end floation. But if the sail were rolled up, I suppose the top of the sail would wrap around the inflatable flotation.

Might be interesting to see how the wrapped up sail "likes" the flotation inflating. Will it look like a snake that just ate a pig or will you hear a loud pop from either the sail or the flotation.

Anyhow.. good thing the sail will likely be unfurled if that ever goes off (unless the rolled up sail collects rain at the top or something like that...)

Hope the test video shows the float inflating when it hits the water - likely with the sail unfurled. Good for you for trying this out.. why not..


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