High Performance MPX Foil/Self-righting Trimaran-The Test Model

WOLF daughter of fire arrow Just pulled off the board -no trimming yet. The hull is mostly finished -just some light sanding and trimming in the bow. Bulkheads need to be trimmed for the deck. Really like the room in the cockpit-superb for a 14' trimaran.

 

WOLF daughter of fire arrow 80 grit sanding done and the deck trimmed up. Still some minor filling and a lot of time studying the deck/cockpit to come. The humidity here is crazy and most of the pictures have a bit of fog even though I wiped the lens every time:

 

Fire Arrow Test Model:



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WOLF daughter of fire arrow:

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Much design work over the last few weeks and lots of changes. WOLF is back to being WOLF though a bit smaller than the original design but not quite as small as I was considering. She would be a foiling singlehanded trimaran if she were to get built. I've resolved a lot of issues and settled on a final design that I'm very satisfied with.
The ama length is still up in the air-I'm building a small concept model to help work out the remaining problems. The boat may use a very small ama-about 7.75'-with a unitized ama/curved piece/crossarm structure that makes trailering simple OR a longer ama-about 10.25'-with the same basic folding system planned for the original WOLF. Regardless of length the ama will consist of the ama planing hull and the "curved piece"(for extra buoyancy)-a
"Two Stage Ama".(see page 171, post 2565)


WOLF specs(tentative) :
LOA 14.8' changed 6/2/18
Beam 15'changed 6/2/18
Target weight 175-190lb
SA-
--upwind: 149 sq.ft
--downwind: 249 sq.ft
--max pressure before depowering/reefing: 1.58lb/sq.ft*
* NOTE-see previous page-post 2697- for max pressure comparison with an F18.
Cost about 60% of WOLF
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Advantages /disadvantages:

1-will not have the capability of taking two people for a ride with high performance upwind . Downwind will foil with a crew weight around 340lb in 6.5-7.5 knots of wind. Excellent upwind performance singlehanded.
2-Singlehanded (200lb crew) will foil in 5 knots of wind .
3-Carbon rotating wing mast, carbon cross arms and carbon foils.
4-Retractable foils(from cockpit).
5-Extremely comfortable.
6-Uses the Fire Arrow Foil System(like Fire Arrow, Gitana 17, Banque Pop and Maserati)-- the same as the original system first used on the Test Model. Two UptiP ama foils-one used at a time-and one wand controlled mainfoil for very early takeoff and capable of substantial downforce all working with a single rudder T-foil.
7-Foiling throughout the wind range -including very light air-the essence of 3D SAILING!
8- Assy Spin/Screecher retracted under the front deck. added 6/3/18
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First WOLF concept model:

 

WOLF daughter of fire arrow:

First model(15.5')-2016


Second and final model(14.8')-2018

 

WOLF daughter of fire arrow: I'm looking at a two stage ama with a total buoyancy of around 150-200 pounds*. Keeps the weight low and with a 15' beam has enough static gust righting moment.
This would be an overall length for the two stage ama of about 7'9" and would allow the whole crossarm/seat/ama structure to be rotated for trailering.
Needs more study, though.......
*Sailing weight of boat between 350-390lb.

 

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Doesn't look like the small two stage ama(under 8') will work. Neither will the pivot system for trailering. Drat.

 

WOLF daughter of fire arrow: I've found the solution and it starts with these mods to the forward end of the cockpit:

 

WOLF daughter of fire arrow: These shots show the completed modifications to the main hull. What you don't see is the mod to the position of the forward crossarm which I had tried to make swept back-but that wouldn't work. This arrangement includes a swept back airfoil on the front of the forward cross on each side. And the mast step(not shown) at the forward end of the cockpit is incorporated into an extra long main foil trunk that intersects the forward cross. It will probably use a folding system I came up with a few years ago. The asy/spin screecher will slide under the forward deck(not shown) and back to the cockpit.
The main traveler will run across the cockpit sole about midway. Oh, and the seats will be extraordinarily comfortable.......
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The two pictures taken from directly above show the differences between the original and modified version. The mod is the right picture:

 

WOLF daughter of fire arrow
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WOLF specs(tentative) :
LOA 14.8' changed 6/2/18
Max Beam 16'changed 6/14/18
CL boat to CL ama hull*-14' added 6/14/18
*Two stage ama consists of ama hull+ curved piece for extra buoyancy
Target weight 175-190lb
SA-
--upwind: 149 sq.ft
--downwind: 249 sq.ft
--max pressure before depowering/reefing: 1.58lb/sq.ft*
* NOTE-see previous page-post 2697- for max pressure comparison with an F18.
Cost about 60% of WOLF
------------------------------------------------
Advantages:

1-Singlehander-will not have the capability of taking two people for a ride with high performance upwind. Downwind will foil with a crew weight around 340lb in 6.5-7.5 knots of wind. Excellent upwind performance with 200lb crew. changed 6/14/18
2- Will foil in 5 knots of wind with 200lb crew . changed 6/14/18
3-Carbon rotating wing mast, carbon cross arms and carbon foils.
4-Retractable foils(from cockpit).
5-Extremely comfortable.
6-Uses the Fire Arrow Foil System(like Fire Arrow, Gitana 17, Banque Pop and Maserati)-- the same as the original system first used on the Test Model. Two UptiP ama foils-one used at a time-and one wand controlled mainfoil for very early takeoff and capable of substantial downforce all working with a single rudder T-foil.
7-Foiling throughout the wind range -including very light air-the essence of 3D SAILING!
8- Assy Spin/Screecher retracted under the front deck. added 6/3/18
9- Boat folds from max beam to trailerable width in about 4 minutes. No waterstays. added 6/14/18
10-Mid (wish)boom mainsheet so sheet is always in forward hand and ext. tiller always in aft hand. added 6/14/18
11-Quickly self-draining cockpit-large scuppers with backflow flap. added 6/14/18
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WOLF Main Foil:
--span--4.8'
--area--3.2 sq.ft
--foil loading--97lb./sq.ft(Compare with Moth+180lb crew=178lb/sq.ft)
--foil section 63412 0r better
--set at +2.5 degrees
--wand controlled
--takeoff-- 6knots boat speed(4-5 knots wind speed)
--retractable into recess in main hull to facilitate beaching w/o foil damage-tips prevent end of foil digging into bottom
--Two set flight altitudes

 

WOLF Rudder Foil:
--span-3.3'
--area-1.32 sq.ft
--foil loading-59lb/sq.ft -at takeoff(61% of mainfoil)
--foil section-symmetrical-9% t/c (so far)
--set at zero degrees with reference to the static wl. Boat will pitch up 2.5-3 degrees at takeoff and level out once it reaches preset flight altitude- approx 3 min. depending on conditions. Rudder foil is a trailing foil and 100% automatic-no adjustment required under sail.
--retractable
--Two set flight altitudes

 

WOLF daughter of fire arrow-- Concept model ready for deck , daggerboard trunk and final filling:

 

WOLF daughter of fire arrow- concept model with deck, crossarm mounts, forestay attach, and daggerboard trunk recessed so foil is flush when retracted(not in these pictures). Long day.......
PS-daggerboard trunk has a hatch so the deck will remain smooth-its drawn in place. Mast step is just ahead of the daggerboard hatch.

 

WOLF daughter of fire arrow- Foils! Hull and deck need lots of filling, sanding, filling and sanding and crossarms + two-stage amas ....and paint(but what color?).

 

WOLF daughter of fire arrow-
picture by Daniel Rowe
Duratec'd the hull and deck- second coat today. Final sanding starting with 220 next. The duratec had to be brushed on and went on remarkably smoothly compared to previous times.
Brown and white or red and white? Or brown, white and black?


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UPDATE-----I spent a bit over 4 hours sanding today-just 80 again. Tomorrow 220-600 wet sanding so no dust. It's damn hot outside!