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Trimaran Ackerman and toe out


morspeed

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I ran a couple of 3d models and found that Timberwolf used to be at 25 degrees heel when the main hull lifted, Lucifer is 20 degrees and the new timberwolf version will be 15 degrees. have you not done any calculations of dihedral angles versus righting moment versus heeling angles?

you will be suprised by the results if you do!

 

No sam. the angle when we fly the main hull is actually just slightly less than 5 degrees

 

 

Thank you for the possible use of your ama moulds.....given that time is short, I am a bit over long boarding and I have a glass factory in the family I was putting out the long shot that there might be a set of female moulds floating round somewhere.

 

I do like the idea of a 8.5 tri as a fast cruiser...love getting out there..but as i said time is short.Getting to the barrier in 4 hours instead of 9 hours (on a good day) would make long weekends out there a little more doable.

 

Very interested in flying a hull at 5 degrees,this would be possible because of the extra bouyancy down low with your new raked back bows?, or are you dropping ama height to waterline lower than your old ama's?.

 

cheers..Gary

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Thank you for the possible use of your ama moulds.....given that time is short, I am a bit over long boarding and I have a glass factory in the family I was putting out the long shot that there might be a set of female moulds floating round somewhere.

 

I do like the idea of a 8.5 tri as a fast cruiser...love getting out there..but as i said time is short.Getting to the barrier in 4 hours instead of 9 hours (on a good day) would make long weekends out there a little more doable.

 

Very interested in flying a hull at 5 degrees,this would be possible because of the extra bouyancy down low with your new raked back bows?, or are you dropping ama height to waterline lower than your old ama's?.

 

cheers..Gary

 

The moulds do produce a hull that needs very little longboarding (that is a major consideration). the advantage of the batten mould over a full female mould is both cost and its easier to secure the core in a batten mould.

I think you could do pretty cheap foam and glass amas, then just build a ply central cruising pod.

 

So flying the hull at low heel angles has to do with the buoyancy of the new amas and the fact that the amas are pressed down a lot closer to the water (i.e. the boat won't flip flop from side to side at rest as much as it used to ).

 

that interested me about your model, you will see a high angle of heel as the hull flies, and that exacerbates the issue you are having between the waterline ama shape level and as the hull flies. My recollection of BMW oracle is that it flies a hull at a pretty low angle of heel ?

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Mr Wolf question: If the boat is at rest (no wind say) for your new setup, if one ama is dipped, how far out of the water will the other ama be? Sounds like you are going for very little dihedral...

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Mr Wolf question: If the boat is at rest (no wind say) for your new setup, if one ama is dipped, how far out of the water will the other ama be? Sounds like you are going for very little dihedral...

 

In zero wind with the boat sitting dead level the deepest point of the rocker line of both amas is 60mm in the water.

 

But that is not the same thing as saying it will not flip flop at all, as with 60mm of the ama rocker in the water there is still not much buoyancy, so as soon as the lee ama "firms up" then the windward one is clear.

 

I have added a new view to Page 10 of the Timberwolf thread to illustrate.

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No sam. the angle when we fly the main hull is actually just slightly less than 5 degrees

 

 

my calculations were based on a normal configuration, not a three hull in "piver" configuration.

 

Im suprised you would optimise your boat so heavily for reaching and upwind in the breeze at the expense of the light airs and running that Timberwolf used to excel in?

 

The three hull in worked for BMWO however they had a much higher bruce number than you I would guess?

 

At what windspeed would you guess you would have the WW ama clear VMG running in this configuration? (assuming small chop not flat calm sea)

 

If its successfull VPLP will be wondering why none of their tris (except BMWO) have ever been setup like this...

 

I have attached a picture of his lastest record breaking tri as an example, we can see one float quite high off the water when its not sailing.

 

I have spent many many hours in Hydromax playing with the height and pitch of my amas relative to the main hull and was going to make them both just touching the water but having the benifit of sailing and helming the sistership Lucifer I will be having them 25mm off the water

NESF2.gif

bp2k.jpg

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Hi Gary. Built this 1.2m tri in 2002. It has a 1.8m foam wing mast. There were 4 of us that built model multis, and I did angle the floats out. Yes it flies a main hull. Just make sure you make the rudder bigger than the boat scale. Have started a 1.2m cat also but have toomany boats and not enough time. Lance

post-10443-141887165433.jpg

post-10443-141887165436.jpg

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Found this some time ago.

 

Bruce Ewing in New Plymouth in the North Island of New Zealand designed, built and raced this one-off bright yellow Trimaran called ThE WING THING. Ever seen a rocket propelled extra-wide yellow banana almost take off from the water headed for the moon? Impressive sight indeed but you’ve got to be a quick-thinking windler to sail this one. (This picture is for you dear friend Bruce!)

Capture.JPG

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Hi Gary. Built this 1.2m tri in 2002. It has a 1.8m foam wing mast. There were 4 of us that built model multis, and I did angle the floats out. Yes it flies a main hull. Just make sure you make the rudder bigger than the boat scale. Have started a 1.2m cat also but have toomany boats and not enough time. Lance

 

Hey Lance, cheers for posting a few pics, love the multi's and it cheers me up to know there maybe a few 1.2mt multi's floating around, been working on this project for over a year and it sometimes feels like there is no-one in NZ who sails these...there is loose talk of us pulling up roots in Ak and setting up camp in Tauranga...anyone still meet and sail these down your way?.

 

Gary

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Found this some time ago.

 

Bruce Ewing in New Plymouth in the North Island of New Zealand designed, built and raced this one-off bright yellow Trimaran called ThE WING THING. Ever seen a rocket propelled extra-wide yellow banana almost take off from the water headed for the moon? Impressive sight indeed but you’ve got to be a quick-thinking windler to sail this one. (This picture is for you dear friend Bruce!)

[attachment=0]Capture.JPG[/attachment]

 

Awesome boat John, that has to be a handful, love the wing mast concept...that boat in storage now?.

 

Gary

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Hi Gary, Im sure we could get the group together again. Here is a close up of HOW BIZARRE she is a bit beaten up now, but still goes well, and no, i didnt copy timberwolf colours - I had them first!!!!!! :shh:

post-10443-141887165529.jpg

post-10443-141887165531.jpg

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Thats a really interesting build Lance, looks like you put a lot of thought and work into the crossmember design. Were the ama hulls built with a female mould or did you build them as one off units?. Is she all glass...

 

Maybe in the future you could get your boats together and we could meet up for a race or two down your way...there seems to be plenty

of IOM sailing in Tauranga..guess you have reallly good sailing locations to meet up at. The place your pic is taken at looks superb...good breeze and flat water..

 

Cheers..Gary

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