16-17' Fixed Keel Self-Righting Foiler

Would this be the ultimate two person boat/family daysailor? Could it work?
LOA 16-17'
Beam 12' (easily foldable for trailering)
Hull+ rig ready to sail weight 160lb.(minus ballast)
Ballast in bulb keel-120lb(self-righting from capsize or pitchpole) only etc.
Crew weight nominal 320lb.(sliding bench seat)
Upwind SA 150 sq.
Downwind SA 300 sq.ft.
Mainfoil on keel strut(at bulb)
Rudder foil
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----Idea is to provide a safe, very fast two person boat that would be designed to foil down wind: round the mark,pop the spin,deploy the wand and whoosh....
----Uses modern ideas from several different types of boat to provide a new kind of sailing experience. Could be configured in a number of ways-for instance single handed main + spin only. Four people (2 adults, 2 kids main+ jib daysailing only).
Design configuration for racing: Two people ,max 320lb (more or less).
----Sliding bench seat P&S-NO HIKING NO TRAPEZE
----100% self righting
----Power to weight ratio off the wind better than a Moth.(W/SA=2.0)
----Small buoyancy pods on outboard of rack


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do everything boat

Doug
Where's yer pitchers?
Actually sounds a good idea, maybe we could have a competition - but first I have to finish and sort out the CB skimmer.

 

Gary, its just an idea at this point-I'm building a more "conventional" monofoiler. But this idea intrigues me because has the potential of introducing people to foiling that would otherwise not be interested,I think. And flying a fullsize keelboat is something I just have to do sometime!
Your new boat-don't remember the details-can you fill me in? Will it use foils in any way for lift?

 

Dumb. Have you really lost it? so now your going to have 2 Foiling project boats that your not working on? brilliant. One no one wants to hear about and another one no one wants to hear about.

 

Wow. You know I'm a big fan of foilers, but I don't know what to think about this. It's hard enough to get performance sailors interested in foilers, now we're talking day sailors. I think if you wanted to produce a boat geared towards fun and family you where closer with the do it all tri-foiler concept (which I didn't think was half bad by the way). This sounds like a contraption. And all for downwind only foiling? You could make a family friendly Tri-foil and have it foil all the time. I would think it might be better to get a 2 handed dedicated performance Mono-foiler class out there before this thing. It might be cool as proof of concept, but I don't think there would be many takers. I'm not trying to put you off of it, my philosophy is "build what you want". I personally think mass foiling is still years and years away, and I'm building a foiler. If you did get it going it would be hard for anyone to argue your Foiling=power to weight ratio theory. Lets just put it this way, can't wait to see it.

Sam

 

Self-Righting Foiler Dinghy

You may be right but this thing would have one thing no other foiler could match: it would be 100% self-righting.
I think that bi-foiler technology offers many options-a super high performance boat like the SR71, Moth or RS600FF,"foil assist", upwind foiling with a fixed keel in a super high performance boat and a tamer configuration that allows you to fly just downwind-like you use the asy spin just downwind. No way would the boat be as fast as a full foiler but boy would the crew have fun downwind!
And the boat could be extremely versatile: you could take the lead off,take the jib off, reef the main etc-lots of different configurations for the same basic platform. More bang for the buck?

 

You don't have to sell me, because I won't ever buy one, but build it and see what happens. After I get the SR-71 finished and working well, I'm going to make one of these for the Ol' family boat.

 

From Gary Baigent:
a boat for all seasons

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Nothing special on the skimmer in the foil department Doug, in fact very conventional - however the double rigs will be wing mast/soft sail combinations and the after rig will be inclining (to get it away from dirty air when sailing on the wind.
If I draw a version of your 16-17 foot craft, it won't have any bloody lead, just water ballast, which can be quickly taken on, or dumped - haven't worked it out how to do it yet.
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Gary, the essence of this concept is that it is self-righting-if you get rid of the lead and lose the water wouldn't you lose that?

 

I confess that I don't see the point here. For a daysailer, the ability to self right is not much of an issue. Crew rightability is.

Either design the thing so it takes a great error in seamanship to capsize it, or make it easy to right if normal errors make it go over.

I don't think able bodied sailors have a problem with the risk/reward tradeoff. They have been chosing boats that way for centuries. If speed and sail carring power are the goals, adding lead is never a speed producing feature.

It seems to me that success "foiling" is related to the ability to carry sail and the ratio of sail power to weight. How much weight would you have to add to a Moth to make it self right? How would that extra weight effect the performance?

 

Keelboats that self-right are MANDATORY in some sportboat rules. The idea here is to stress the easy to sail ,safe, aspects of this concept though off the wind the thing would probably beat a Melges 24-another boat known for a great downwind ride.
So you want to know whether or not a Moth could be self-righting?
First, there is another singlehanded foiler you should know about:
the RS600FF: 141 sq.ft. SA ,same beam as a Moth with a trapeze,allup boat +rig weight=167lb(2.5 times a Moth which weighs 66lb allup).
Self-righting Moth-slightly bigger hull with RS type rig =80lb; 87lb. ballast=
self-righting "Moth". So many people get hung up about foiler weight when comparing different foilers-its not weight alone that matters-its the power to weight ratio-and on my proposed boat that ratio is better off the wind than a Moth. And the RS600FF is equal to or better than a Moth upwind and downwind.
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There appears to be a potentially serious issue with this concept and that is the fact that to do what it is supposed to well it will have to have a fairly narrow main hull. The buoyancy pods will prevent it going too far along with the keel but it may strike some as too "tippy"-what do you think of that being a problem?

 

Do those sportboat rules allow lifting foils?

Is the "self-righting" part of the rule to keep fast boats out?

Is a J-24 'self righting'?

Are those sporboats 'self righting' from 180 deg?

Define the terms.

 

Sportboat foilers?

Some more thoughts......(from a post on SA)
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Included here are the numbers for a FIXED KEEL SELFRIGHTING SPORTBOAT FOILER:
Here are the numbers with ballast/displacement ratios shown for the canting keel boats and 3 Fixed-
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In this thread I've talked about and shown preliminary numbers for canting keel Sportboat Foilers as well as indicating that a fully selfrighting foiler sportboat is possible. In this thread I've gone into the various ways bi-foiler technology could be used on Sportboats(see below).No,really study below!In the other thread I've talked about Mirabaud and how unfortunate it appears to be that there is no INSHORE Sportboat category that boats like that could fit into.
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Maybe this will help:
1.) " After all human beings are almost entirely water and have proved their worth as movable ballast." Steve Killing
2.) "Today we use all types of movable ballast,usually human..." Doug Culnane
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Every fast sportboat uses human movable ballast. However, the two sportboats presented here also used solid movable ballast AND ARE SELF RIGHTING:

Sport Boat Foilers
With the phenominal new Super Foiler Mirabaud making history NOW it seems like a good time to revisit these ideas I've thought about and worked on for several years:
There are some really exciting sportboats available now and at the end of this post are some interesting websites particularly the one with comparison statistics of a few current boats. For purposes of this post I'll define sportboats as high powered keelboats between about 20' and 40'. Some boats are much higher powered than others as you'll see in the comparison table. They should be able to plane (or foil). Ocean racing versions should be self-righting.
After doing an exploration of the feasibility of a foiling 60' monohull keelboat
, it occurred to me that the next big advance in monohull foiling would probably be with a boat that fits the definition of sportboat so I 'm presenting very preliminary numbers for a two person and three person "Sportboat Foiler":
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Two Person
---LOA 24'
---LWL 24'
---Beam 18.6' (overall, incl. racks)
2.4' at waterline
---Draft 6.5' keel,foils retractable
---Sail Area 586sq.ft. upwind and downwind
---Boat weight,incl. rig and ballast-1100lb.
---Ballast 490lb. (110° canting keel) 44% ballast/displacement ratio w/o crew
---Displacement (incl crew)-1420lb.
crew-320lb.
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Three Person:---LOA 24'

---LWL 24'
---Beam 10.73' (overall incl. racks)
2.4' at waterline
---Draft 6.5' keel and foils retractable
---Sail Area-600 sq.ft. upwind and downwind
--- Boat weight- including rig and ballast-1100lb --- Ballast 490lb.( 110° canting keel) 44% ballast/Displacement ratio w/o crew
---Displacement, incl. crew 1580
crew-480lb.

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Three Person FIXED KEEL SELFRIGHTING
---LWL 24'
---Beam 18' (overall incl. racks)(2 on trapeze optional)
2.4' at waterline
---Draft 6.5' keel and foils retractable
---Sail Area-650 sq.ft. upwind and downwind(except in light air then 1200 downwind)
--- Boat weight- including rig and ballast-1100lb --- Ballast 490lb. 44% ballast/Displacement ratio w/o crew
---Displacement, incl. crew 1580
crew-480lb.[/color]
Take Off Boat Speed is 6.5 knots which would be achieved in a 6-7 knot wind with 650sq.ft SA
Configured for early take off using a 63412 section at a mainfoil angle of attack of 6 degrees and a 20 degree mainfoil down flap angle.
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Other comparisons:
-- -Sail Loading(weight divided by SA)- Two
Person=2.42 lb. sq. ft. ; Three Person= 2.69 lb. sq.ft.; Three FIXED 2.43(#2 & #3 this ratio better than a MOTH)
---Mainfoil Area- Two Person=7.1 sq.ft. ; Three
Person= 7.48 sq.ft., Three Fixed 7.64 sq.ft
---Mainfoil Loading- Two Person=158lb. per sq.ft.
Three Person=169 lb. per sq.ft.
---Sail area per sq.ft. mainfoil area- Two Person =82.5 ; Three Person=80.2 ; Three Fixed=86.8
Note: Two person takeoff profile is approximately equal to a Moth with Rohan Veal aboard; Three Person approx. equal to a Moth with a 160lb. person aboard.
---D/L Two=45.6 Three= 51
---SA/D Two= 74.3 Three=70.9 Three Fixed=78.4
---SCP/total weight Two=42% Three=34% Three FIXED 38%
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Three person fixed keel would be 100% selfrighting w/o crew interaction:BALLAST/DISPL. RATIO SIGNIFICANTLY BETTER THAN T780. Ballast in this keel is not used for sailing RM-just for RIGHTING. Boat sails with 20 degrees veal heel adding 21 % to RM.
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Both canting keel boats would be designed to be rightable by moving the keel; and a 100% self-righting foiler(no crew action required) is possible------------------
Weights for the hull and rig were derived from EXISTING boats that have hulls ,for the most part, twice as wide with over double the area anticipated with these boats. The hull would be very narrow -not much over three feet wide(at the deck) with possible flare out forward for a minimal cuddy cabin. The hull would be double-ended. In comparisons with the other boats in the table below the Sail area to wetted surface ratio of both versions above is probably greater than any other boat even INCLUDING the wetted area of the hydrofoils.(8.27/1 vs. 4.7/1 for the Martin 243).
I did this to show how incredibly close we are to having one of these boats actually built; the technology required to do this is available now and I hope it won't be long before "Flying Keelboat" really means flying...
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Patented K Foil would be used on Three Fixed


BALLAST/DISPLACEMENT RATIO= 39%; the foilers above 44%
K FOIL ON SA: http://www.sailinganarchy.com/editor/2004/...october2004.htm
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Weights for the hull and rig were derived from EXISTING boats that have hulls ,for the most part, twice as wide with over double the area anticipated with these boats. The hull would be very narrow -not much over three feet wide(at the deck) with possible flare out forward for a minimal cuddy cabin. The hull would be double-ended.

 

Answer the questions Doug.

What existing rule are you designing to?

If you are not designing to an existing rule, why the need for self righting?

Define self righting.

 

Hi Doug.
How many foilers have you seen begin foiling when not pretty much bolt upright and how to you propose to maintain that in a keelboat?

 

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This is just an idea right now-but it would fit into the same category as a Bongo ,a hopped up Laser Stratus, a Flying 15 etc. except that it would be much faster downwind.
For a sportboat, the aussies have a "sportboat rule" but I don't the rule exactly. As I understand it , a boat must recover from a knockdown w/o crew assistance.
I see real potential problems that have to be explored. Most small keelboats don't go fast enough to throw anyone overboard. This might be the exception while foiling downwind: if the crew was thrown off the boat could they get back before the thing righted itself and sailed off? Scary.