----------- proa - the outrigger sail boat - today - - fritz roth - - proadesign --

>>>>>> video > hinged vector fin proa

...... >>> easier to trailor .... beach ..... more draft when needed .... more comfort > flying !

..... > for more on the new hvfp at the end and > > > http://blog.proadesign.com

I developed this
outrigger sail boat
over the last 2 decades

after I had a tri & a cat -
then a traditional proa
with a outrigger float on it

a 23` & a 31`have proven themselfs now
for over 4 winters sailing the strait of gibraltar & such in bft 10 -
sailing off a beach with breaking waves so high as the boat is wide -
then surfing back in & landing on the beach again -
anchoring with 1/4" nylon rode & a 5lbs anchor in a white squall -
beating out off marina bay towards the west -
when the whole bay of gibraltar was white -
I have been so convinced of it now - that I have started a 88`already -



the

idea

behind

the

concept

is

the

following

have a boat as long as possible for comfort underway & anchoring -

because one can anchor almost anywhere there is no need to go into a marina -

meaning there is no need to have an engine -

having total control under sails alone

( you can turn on the spot - go both ways - standby & check things anytime )

having good cruising speeds with as little as possible of an sailarea - 1000sf / 88` - no need to reef or change sails up to 8 bft - beating - 10 running - to be safe from any breaking freak wave or gust



the

proa

today

modern proas can do a lot of things - the polynesians could only dream about - the outriger sailboat of today - is non capsizeable - fast to change direction - safe to manoever even in thight spots - can any time go on stand by - to look around and see what`s going on - turn on the spot - like with a twin engine power boat - to land on most beaches - leave again - without turnig the boat - they have - once underway - no leeway it all - and all this - with a boat - that weighs only one half of a catamaran - has only 2 small ruders - 360 - on the windward side of the mainhull - no turning or moving mast - no dagger - center - steering boards - nothing more to move or control - exept the sheets for the sails -



general

requirements

for good performance - hard on the wind - you need not only little resistence through the water - but little aerodynamic resistence from the waterlinie on up as well - that is why the crew is seated inside the boat - ( 1 ) the bridgedeck is aero dynamically shaped - ( 8 ) and up to about 30` loa ( 13`wide ) because it is lighter then - one piece - can be trailered high up -

sailing the proa - standing by - changing directions

you are sitting broadside to the wind in your boat - the sails are lose - you are drifting slowly to leeward - you pull on a sheet - the boat moves in that direction - it`s that easy- with the windward sail - ( 3 ) you even can turn on the spot - with the main * you go to the right - with the windward sail to the left - with the roller jibs ( 2 - these are just sails on a tube on the stay - control line ( 2 ) going from the top of the tube to the other - so if you pull one roller open - it closes the other automatically ) you can make the boat fall away from the wind - with the main sail you shot up to the wind - make the boat selfsteer -


* the main ( 5 ) ist on a mast with slides to leeward - ( 4 )
so without having a turning mast - you have a clear flow on the leeward side


steering is by 2 fin ruders - 45 on the side of the main hull - ( 7 ) so you can beached most anywhere - without damaging them - or having to pull them up - they are controled by your feet -
slings in the lines going to the bell crank on the balanced ruders - so they can turn which ever way they want to - left & right - actually - you do not need them - because the boat can be steered by itself - depending on the sail setting - exept in large waves & swells it makes for a nicer - straiter sailing - if you have the ruders - bow & stern -


the self leveling 2 stage fin - ( 6 )

sailforces + the windforces on the boat combine to create a center of windforces somewhere 1/3 up the mast - if now you have an angled fin to windward - you have a means to counteracting these forces - you could put the fin to leeward and lift the outrigger - but you would have the same problems as a trimaran - diagonal capsize in waves large enough - you would have very unstabil boat - like it is very easy to hang up a pendulum - but try to stand it up alone - further more - imagine a freak wave - hiting the boat side ways - with the present setup - you have no wory it all - ( just make sure the structure holds up ) but the other setup is doomed - before the wave even hits - that is why - in such conditions - you do not want to let the wind & waves - be on the wrong side - ever -

now - if the outrigger wants to come out of the water - the fin`s lower part pulls it down - when the outrigger wants to go down into the water - the upper part of the fin lowers the vector more to the horizontal - making the outrigger want to come up - changes in bouancy of the fin helps in each case - if - as some have told me - the fin would come out of the water - through wave dynamics - as it never has with this configuration - then the center of lateral action moves violently forward - the boat shots up into the wind - I have tried this on a model without the lower part of the fin on it -

for more information check out ... www.proagenesis.org .... pictures & other languages
www.proatech.org .... for technology files & videos !
www.interproa.org - is for establishing a sailing basis .....

 


fritz roth@--------------

 

 

 we have now finished the design of a 2 mast proa -
 it should even better selfsteer then the 1 mast version -
 and can be totally sailed without the roller jib -
 before the wind the forward mast sail can be sheeted 
in a backward beating position -
 because the jib is not needed in a storm it all - 
 it can be much larger for light air performance -
 because they are on a stay 12 to leeward - 
they do not back wind the mast sail -
 --------------------------------- 2 mast proa
and here is a 3 mast version ! 
it has the same mast sail area as the 2 mast rig - 
but a lower center of effort - 
it seams this would be the choice on the larger boats -
it can have a cockpit on the bridgedeck -
or a long cockpit in lee with 2 steering stations 

and here we have the new hinged vector fin proa .............

 

and here a top view of the hinged vector fin on a flying proa .......

and here the front view from the hinged vector fin proa ......

to contact me - fritz_roth@

for more on the new hvfp > > > http://blog.proadesign.com

if you are interested in a scientific discussion of the vector fin proa technology  ...
you are invited to
  http://groups.yahoo.com/group/proatech  
if you are interested in a club around these outrigger boats   http://groups.yahoo.com/group/proagenesis  
if you want to just build to present technology yourself   http://groups.yahoo.com/group/proadesign

galactic design