Dinghy Cruiser /Racer Design

[Doug Lord]

Hopefully, this thread can pick up from the "Sailing Dinghy Design" Thread with more of a emphasis on cruiser /racer dinghies.
Seems to me that a possible solution to a small- 16'(4.8m)-20'(6m)?-cruising capable dinghy that could also perform well might be the addition of a manually controlled retractable canting keel: it could be locked for cruising and unlocked for maximum power.
Looking forward to hearing what others think....

[spoedvraat]

Hi Doug,

Myself and Ian were discussing a thread exactly like this yesterday, so thanks for the effort, if you don't mind us crashing the party. For posterity's sake, I'll put down my requirements again.:


Requirements for the Dayboat:

Where:
The boat will be sailed on inland and fairly rough coastal waters. The worst case scenario is probably the same as for an oceangoing boat.
I will try to apply sensible safety factors when designing critical components.

How:
The boat will be singlehanded often, but will have to carry 4 to 5 people on day-sails.
This means I must be able to launch, rig, de-rig and retrieve the boat alone.

What:
Various options exist for construction, I prefer strip-planking and glass/epoxy reinforced approach currently. I haven’t done this before, just stitch-and-glue. I have enough basic knowledge of composites to feel confident I can do the necessary work.

When:
The boat will most often be used for daysailing during the weekend, and might have to do a three day trip once a year.

Broadly stated imaginations……:

I want to have a boat which can be used to chase the local racing dinghies, which are mostly 505’s, FD’s, some local classes, and a smattering of 49’ers (which I won’t try to catch.) I thus require a light boat which is powerful enough to plane quite easily, with crew on trapeze if required.
However, come the summer holiday I want to use the boat as a basic cruising dinghy, on which I can cover some distance in marginal conditions, which means high stability, adequate freeboard, predictable (even docile) performance, reef-able sailplan and enough storage for the “stuff.”
The concept I want to attempt is probably not a new one, but currently it revolves around the idea of having two options of centerboard/keel, and two of rig/sailplan, thus:

Sailplan/Rig: Keel/Centerboard:
Racing mode: Powerful, large roach Unballasted foil
Cruising mode: Smaller/docile Ballasted Keel

In cruising mode there must be a headsail furler, lazyjacks and reefable main.
The boom is higher up the mast, and the roach of the cruising main is much less. The mast can be raked back to balance the helm, or we go to decreasing the size of the furling headsail as well to balance.

The “furniture” inside the boat to make it nice for cruising must be removable for racing, and this is probably one of the hardest things to do elegantly.

Further ideas:

I like the concept of an open boat which has a double bottom, so no self-bailers etc required. Water coming on has no option but to disembark, pronto. This is nice and safe.

Double rudders are probably equal to singles all things considered (except cost…,) and leave a nice space for outboard engine mount in the center of the boat.

A bimini is non-negotiable in the summer down here.
An easy arrangement for a boom-tent would be very convenient when in cruising mode.
Further we have thought of using rolled-up (lengthwise) inflatable mattresses as buoyancy under the seats, to double as beds when unstowed and unrolled for the night.
A battery is required when cruising, as we need to drive the VHF, GPS, tillerpilot, running lights and fishfinder as a minimum.

And as I start churning numbers, the following seems to emerge:

Loa 5000
Beam 2000
Sail area 14 m² (white sail area) (main 9.5 m², jib 4.5 m²)
Mass 120 kg (all up, excluding crew, racing mode)
Mass 80 kg (hull only, racing mode)
Construction: 6mm Cedar strip with 1 layer 300 g/m² plainweave either side. Resin:glass = 1:1

Cp 0.6

[PaulCoffin]

I'm not sure if this is within your range of possibilities: I've always liked the Marples designed Cyclone 23 trimaran. It seems to meet the requirements for speed, comfort, and overnighting.

http://www.boatdesigns.com/cgi-bin/store/web_store.cgi?page=cyclone23.html&&cart_id=2295227_23173

[Doug Lord]

That's a great looking design!

[Ian]

I hope no one minds my copying my previous post to this thread. This does seem the best location for much needed advice.

--------------------------------------------------------------------------------

I am working on a 16 foot cruising dinghy. Twin side by side center-boards fascinate me. Tandem (fore and aft ) boards and keels get a lot of press but not the alongside arrangement. It's extra work to build, but it would allow me to get the case out of the way. I could put the cases on either side of the well and built into the seat fronts. I would be planning on using both boards at once rather than alternately, as in lee-boards. It seems that I could get shallower draft for a given aspect ratio. Also, I suspect the heeling moment would be reduced as the center the combined lift would not be so far below the heeling axis. Is this true? It seems obvious, but what is obvious is not always what is true.
Side by side boards would not interfere with each others hydrodynamics like fore and aft boards. I can see that ventilation at the root of the windward keel might be a problem in a keel boat (I suspect that bilge keel boats use a little extra area and the more vertical position of the lee-ward keel, due the splay, to make up for this) but I do not believe that a dinghy, which would be sailed more upright, would encounter this problem. I would not consider splaying the boards for practical reasons.
I do, however, worry about not having a nice long single center-board to use as a righting lever should I turn turtle. My other plan is to have a single offset board.
I was planning on having a considerable amount of water-tight storage fore and aft and in the side benches. I have since decided to make the starboard bench mostly free-flooding. It seemed to me that I might be designing a boat that was too stable up-side-down. The starboard bench would have wet storage. I feel that, if I can use my weight to easily submerge one side of the inverted boat, it would be possible to roll her back up. I noticed that the Drascombe boats have very slim, low bouancy side benches, perhaps for this reason.
I would like to right this boat very quickly in adverse conditions as I intend fairly extensive cruises in very cold water. She will not capsize easily--probably never (except for testing purposes) but it would be unseamanlike to be unprepared.
I would appreciate any comments whatsoever. I am not very experienced with sailing dinghys though I have had a fair amount of sea time in on very large yachts. It is not at all the same thing. I have had no experience righting dinghys any larger and heavier than a laser. Go ahead and pile on the suggestions! Thanks.

[Guest]

Check this design out. http://www.colsonyachtdesign.com/designs/TrailerSailer55.htm

[Doug Lord]

That is the coolest little daysailer/ weekender I have EVER seen. What a great job! Too bad there wasn't more info on the site...

[Guest]

I saw it in a copy of Australian Amateur Boatbuilding magazine a few months ago. It is quick by all accounts and it sounded like it fitted the design brief well. There is a bit more information available on Colson's web site http://www.colsonyachtdesign.com

[Ian]

Boy, that's a great design. Not for me though--more what Spoedvraat is working on. Working as I do with a bunch of conservative woodenboat builders, I incline more towards a traditional designs--for this boat anyway.

[SailDesign]

I did a 24-footer a while ago, ballasted centreboard, little cuddy cabin, "dual-purpose" rig, the works. If you're shorter than 6'2" then the cabin could be prettier :)
http://members.aol.com/Saildesign/private/scbweb/peregri2.htm

Steve

[Doug Lord]

Great design Steve-and terrific design philosophy as well....

[SailDesign]

Thanks, Doug. That is/was a great little boat. I kind of lost track of her after Phil sold her on, so if anyone knows where she is now, I'd love to hear..

Steve

[FoveauxSailor]

Hello Guys

I too am working on the design of an 5.6m "Expedition style' row/sail dinghy, something that will foot it with Ian Oughtreds Ness Yawl/JII designs in terms of "tradition" but able enough to give some of the modern one designs something to think about. She will use the rig from a 470 dinghy (12.7m^2) in bermudian mode and a balance lug (about 14m^2) in traditional mode.

Incidentally the deck plan will be based on the Drascome lugger.

Currently what has got me stumped a methodology to determine optimal areas for the rudder and daggerboard. I know keelers are based on sail area, starting at 1.5% for the ruddr and 3% for the keel. However looking at any dinghy plans jsut gives me a headache as they vary so much. For my boat I paln to use a Naca 0012 for the rudder and probably 63015 for the daggerboard.

Any thoughts appreciated

Thanks - Foster

[Ian]

Hello Guys

I too am working on the design of an 5.6m "Expedition style' row/sail dinghy, something that will foot it with Ian Oughtreds Ness Yawl/JII designs in terms of "tradition" but able enough to give some of the modern one designs something to think about. She will use the rig from a 470 dinghy (12.7m^2) in bermudian mode and a balance lug (about 14m^2) in traditional mode.

Incidentally the deck plan will be based on the Drascome lugger.

Currently what has got me stumped a methodology to determine optimal areas for the rudder and daggerboard. I know keelers are based on sail area, starting at 1.5% for the ruddr and 3% for the keel. However looking at any dinghy plans jsut gives me a headache as they vary so much. For my boat I paln to use a Naca 0012 for the rudder and probably 63015 for the daggerboard.

Any thoughts appreciated

Thanks - Foster
Hi, I am glad this thread is attracting some attention. I used "Principles Of Yacht Design" for my final decision on area. It has 3.5% with a .75% spread for keels (down to 2.75% for outright racers) and 1.4% for rudders with a lower limit of 1%. I went for 3.5% and 1.4%. My aspect ratio will be about
0.3 and I will use a eliptical planform of the type that is based on a straight quarter-cord line (out of the same book). It looks a lot like a spitfire wing. I believe that I will use the same sections that you are. 12% maximum cord. My sail area is 13sq.m. split into standing lug main,jib and mizzen. Thats at the high end for pure cruising dinghies--but low for a serious racing dinghy.

[FoveauxSailor]

Hello Ian

Have you sailed a standing or balance lug before ?? The seems to be a bit of a lack of people who have really worked with these rigs to extract maximum performance with modern low stretch line and really good sails (I know there are quite a few designs done, like Oughtred and Irens but I mean actual sailing to determine the tricks/gear needed to get them to optimal trim etc)

The best I've come across is Tom Dunderdale at Campion Design, but I don't like bugging the guys who have to make a living at selling plans etc (well actually I love talking with them . . . but it isn't really fair if you know what I mean)

Anyhow with a balance lug He uses a kicker (or vang) a downhaul (plus an "emergency" backup loop, and a kicker on the part of the boom in front of the mast. He gets very nice sail shape. But some photos I've seen appear to get as good a shape without the extra bits ???

Any thoughts guys

[Ian]

Hello Ian
Have you sailed a standing or balance lug before ??

Hi, no, the only experience I have of a standing lug was one I made myself some years ago as an experimental canoe sail. I used a tan-bark coloured polyester cloth--not sail-cloth-- and cut it using techniques I vaguely remembered from a very old book I had once read on how to cut your own cotton sails. I cut a curve into the luff and head and sewed the sail stretched out losely to a tightly stretched boltrope. It set wonderfully. The cloth I used was just stretchy enough for this technique to work perfectly.
As you have no doubt read, the lugsail is much less prone to twist than other sails (which is pretty helpfull if you are not using an boom and kicker).
From photographs I have seen in many books and magazines, the dipping lug sets particularly well. More of a hassle to handle of course. I get the impression from my reading that a standing lug should not have an extremely highly peaked yard--but a high peaked yard works fine on a dipping lug. That might be incorrect. I will be using a boomless sail so I have drawn a sail with a low tack and high clew--trying to balance the sail area around the extended line of the sheet. The idea is to get a sail that--like a high cut yankee jib--can be sheeted from one fore and aft position. I will use a two part sheet. The lower sheet block will be on the rail and the dead end position will be movable. It will be possible to move the dead-end from its usual position on the rail near the sheet-block to the centerline for windward sailing--thus moving the sheeting angle inboard. Experience will probably tell me that I need a second dead-end position further forward along the rail to control twist on a broad reach and run. I will find out. A friend who has raced double-ended boomless standing-lug rigged boats in a local informal class, tells me that they have only a single sheet and move it from side to side as they tack, hooking it in different positions on different courses. They also have no rudder and steer and tack by moving their weight around. I believe that there is a-- Saint laurence skiff?--that steers in this way. I would like to see these boats myself.

[spoedvraat]

I have been busy doing important work on a CNC machine, which will make my life a lot easier when building of the boat starts, and was pleasantly surprised to see the new thread has seen some traffic.
The first images of my boat is posted in the gallery (sailboats/monohull), so please have a look, critisize, rip apart etc.

[spoedvraat]

HI Foster,

Here is an intriguing write-up of "rules:"

The centreboard should be about 4 per cent of the sail area. Marchaj
There should be about 1sq ft of centreboard area to 40sq ft of sail area; in light craft the rudder area should be half this, while in heavier craft it should be still smaller. John F Sutton Comment: Your guess is as good as mine...
A rudder area of between 8 and 10 per cent of the total lateral plane or underwater profile is the desirable size for a sailboat. F S Kinney
(The hyperlink is http://home.clara.net/gmatkin/therules.htm)

I went larger on the centerboard and rudder than this on my first little dinghy, and she sails beautifully balanced and points very well for a gunter-rigged boat. (3.5 metres long, marine ply, weighing approx 50-60 kg rigged.) As soon as I can find the drawings again, I'll post the exact sizes of sail area to centerboard and rudder areas.

[Tim B]

Interesting thread guys, and an interesting project

You'll be pleased to know that this is not the first time this question has arisen, and for a 5m daysailer/cruiser, this is what I came up with...

Length 5m
Beam 1.5m
Loaded Displacement 600Kg
Unloaded weight 220Kg
Keel bulb - 100Kg

The use of a keel adds the necessary safety factor for cruising, which a centre-board may not, but it can always be redrawn (in fact I would redraw it before I started) but just so you have some idea, here is a rendering from the old drawings.

Cheers,

Tim Brocklehurst

www.marinedesign.tk

[Doug Lord]

Interesting design Tim! I like the keel idea as well : I'm slowly putting the ideas for my boat together.At this point she'll be 18'LOA(5.48m),3.5'(1.06m) Beam with a 55 degree retractable, lockable canting keel using a retractable "wing"(kFOIL) on the bulb for the extra lateral resistance.
Still working on further details except to say the canting keel will probably be manually controlled or at least backed up manually. She'll have a high power to weight ratio and an asy spin.....

[Tim B]

Keep it simple, Lorsail. 18ft sounds very small to do the Canting keel reliably. I guess you could use a block and tackle system of some kind, but check out the loads that are present just from moving the weight... and triple it for safety. I reckon that it would be difficult to do it the hydraulic way on anything less than 30 foot. That said, rope and a winch would work. it just wouldn't be as compact.

Anyway, I'd be interested to see what you come up with.

Cheers,

Tim B.

[Doug Lord]

Thanks, Tim. An 18 seems perfect to me to take advantage of the power of a canting keel. I have an engineer working with me on it and we think it can work exceptionally well. We're looking at electro-mechanical ways to move the keel with manual backup and a locking method.Also the keel must retract 100% except for the bulb/kFOIL combo.
So there are interesting design challenges -I wish I could work on it full time!

[spoedvraat]

Interesting thread guys, and an interesting project

You'll be pleased to know that this is not the first time this question has arisen, and for a 5m daysailer/cruiser, this is what I came up with...

Length 5m
Beam 1.5m
Loaded Displacement 600Kg
Unloaded weight 220Kg
Keel bulb - 100Kg

The use of a keel adds the necessary safety factor for cruising, which a centre-board may not, but it can always be redrawn (in fact I would redraw it before I started) but just so you have some idea, here is a rendering from the old drawings.

Cheers,

Tim Brocklehurst

www.marinedesign.tk

Hi Tim,

Nice looking boat.

What was the sail areas, and how did she go ?? At 1.5m beam she seems slender by today's skiffy standards, but with the ballast below it makes sense.
I am a bit worried that I'm going overboard ;-) by taking my boat to 5 m length, beam of 1.9 m and the addition of a bulb of approx 80 kg. It looks great on the stability curve though.......

The questions do arise thick and fast however: Is there a standard for how high the boom must be above the cockpit floor, so the average guy can get under it when tacking. Too high is obviously bad.

And on the subject of asking silly questions, how does one really determine the shape of a sail mold during sail design. The curve in the luff adds draft when the luff is pulled straight, but how much and how is this determined.
Or are we left at the mercy of the big sailmaking guys with the expensive software?
Is there anything written somewhere about sail design, especially asymmetric spinnakers? I'd be willing to pay good money to get my hands on material like this, but I can't seem to find it.

[a stevo]

block and tackle canting keels
chris sayers 'Navman' first minitransat had just this system controling the canting keel. that said crossing ceans doesnt really require repeated rapid movements. structually it shoulnt be too dificult.

how about loading it onto a reversible sheet winch with a continious loop of rope holding it. that way there is no tail and spaghetti problems. and the keel is held rigid on both sides so that it can not swing further to windward if things get airborner.

really if you are just after a cruising dinght grab and old FD,505 or light weight sharpie and reduce the rig by 30%. give it a little keet if you wish then roberts your fathers brother.

[Tim B]

The suggestion I posted was just a very quick model of the hull (which I am not particularly happy with). It has no sail plan as yet, and I'm not entirely sure of the stability curve (because I'm not happy with... etc.) basically, it is just a quick mock up which I produced the last time someone asked a similar question, and I haven't had much time to do anything to it. If you are interested in using a similar hull then I may be able to have a more serious look at it in a few weeks, when I have less work on.

The canting keel: Yes, the reversible sheet winch would work well, and could, potentially allow a greater angular movement. the attachment to the hull or bulkhead should be damn strong though.

Booms: Somebody deep in a lab doing ergonomics has probably thought of this one. certainly too large a gap reduces the sail's loading at the root, thus losing power, but then, losing the helmsman doesn't help either. some boats have high booms, some low, I would have thought that between 3' (for a racing boat) and 4' (for a cruiser) would be about right.

Sails: Not my best area of expertise really, there is another designer, Steve Baker, alias SailDesign, who could probably help you.

Good luck,

Tim B.

[SailDesign]

Sails: Not my best area of expertise really, there is another designer, Steve Baker, alias SailDesign, who could probably help you.

Sadly, I always defer to a sailmaker. When owners discuss sails with me, it's usually the "Send the sailplan to Shore" variety of conversation, and I like that. :) One less thing this jack-of-all-trades has to remember.

STeve

[spoedvraat]

I suppose it's back to Larsson and Eliasson then, to see what I can glean from those learned pages. There must be someone somewhere who has done the math and will give me the formula........

[Doug Lord]

For some up to date info on molded sails and asy spins check out the book with the title above by Brian Hancock published by Nomad Press ISBN number 0-9722026-0-9 The book can be ordered thru The Independent Publishers Group 814 N. Franklin St..Chicago,Il. 60610
or call Nomad Press at: 802-649-1995 or ,of course(probably) Amazon..
For boom height on your own boat I would go with the lowest you personally feel comfortable ducking under- you can set it up any number of ways to test before deciding.

[Stephen Ditmore]

What if instead of a canting keel you had an (upside down) T shaped keel where the endplate could be rotated. At one end of the endplate could be a ballast disk - round in planform, perhaps ogival in section. The whole thing could be raised and lowered vertically. The ballast could be moved using a lever at the top to rotate it to the windward side via a shaft inside the main foil.

[Doug Lord]

Stephen, interesting. I'm not sure the ballast could be moved as far to windward as a 55 degree canting keel. And I think the wetted surface would be less using the kFOIL™(retractable bulb mounted wing). This system would be completely retractable.
I think I get your idea but could you post a hand drawn sketch?

[Matthew]

Briefly, to go back to the lug rig thing, we (Swallowboats) have tried them a lot, and still can't get them to be quite as close winded as the standard bermudan sail. For some reason boat speed drops off dramatically when you pinch up that extra 5 degrees or so.
I can see the advantages to the boomless standing lug (fewer spars) but in my opinion, it is always best to have a boom and so make it a balanced sail.
Reasons are the huge sheeting load of the boomless sail, the fact that sheet angle is so important, the difficulties in tacking and sheeting arrangement, and most importantly, that it twists massively when off the wind, setting up horrible rythmic rolling, the only cure being to sheet in.
I noticed that Nigel Irens added a boom to his Roxanne and Romily designs. It just makes sense.
If anyone can figure out a dipping lug system that is comparable in tacking time and ease, to the bermudan, then lets have it! The dipping lug is an incredibly powerful sail for its size, and for spar length, but it's a real pain to short tack. A great auxilary sail though for motor sailors, though only Bolger seems to use it that I know of.

To go back to the daysailor/racer idea, we are working on a 17ft daysailor to be finished in the next few weeks, that will satisfy part of the brief. (Becuase she is a double ender, she has no planing ability, but may give racing boats a run for their money when the wind is light and they can't plane).
We were also worried about CB and rudder area, though our previous designs have indicated that the rudder area can vary hugely depending on hull design, and still be effective. Our double ended hulls have a small (1" by 2") keel running full length, plus smaller bilge-runners, which give the hull a lot of directional stability. In a following sea or driven hard, they never feel on the edge of control, despite a relatively small rudder area. The downside to this is that they take longer to go about, and for us, this is the governing factor on rudder size.
With regard to CB size, the smaller, the worse the performance in light airs. Im sure most of you know that anyway.
Anyway here's a pictue of her:
http://www.swallowboats.com/storm17/Colours1/s17colour2.jpg

And you can see more at

http://www.swallowboats.com/storm17.htm

By the way - interested in your revolving T keel idea Stephen.... Have you done any further work on it?
Also, what is the kFOIL system exactly? Is it just a canting keel?
Best Wishes
Matt

[Doug Lord]

Beautiful boat!
The kFOIL™ is a(patent applied for) lateral resistance solution for canting keels and low aspect fixed keels. It is probably not going to be as high performance as CBTF(upwind) but takes up no room inside while allowing a single wing or dual wings to be deployed from a slot in the bulb. The foil(s) are deployed as the keel cants to make up for lost keel area. Variations can allow a single pivoting wing or dual pivoting wings. The idea is to provide the lateral resistance needed upwind when the keel cants(or as a fixed keel heels) and then for the foil to disappear downwind and in light air.It is particularly suitable with a canting keel that retracts....
Check out these retracted and deployed illustrations:
http://www.rcsailing.net/forum1/data/wgorgen/20043312449_kFOIL102.jpg

http://www.rcsailing.net/forum1/data/wgorgen/20043312541_kFOIL201.jpg

[Ian]

[If anyone can figure out a dipping lug system that is comparable in tacking time and ease, to the bermudan, then lets have it! The dipping lug is an incredibly powerful sail for its size, and for spar length, but it's a real pain to short tack. A great auxilary sail though for motor sailors, though only Bolger seems to use it that I know of.]

I read an article in a British magazine on a local type of dipping-lug that is tacked by pulling the clew right around the luff with the sheet (the lazy sheet is lead forward of everything). It occurs to me that the hardest part about tacking in this manner is the difficulty of getting the heel of the yard around the mast. It would seem to me that if you had a second halyard that was attached to the yard near or just above the ballance point and was set up with a little slack in it after the yard was hoisted, it would be possible, when tacking, to slacken the primary halyard untill the yard hung almost verticaly from the secondary halyard and would thus swing easily around the mast. If the primary halyard was rigged like the throat halyard of a large gaffer with a two part purchase, the dead-end of which returned down to deck to finish on the upper block of a 'jig'--it might be possible to lower and re-hoist the yard sufficiently with the jig-purchase. If I had a boat rigged with a dipping-lug lying around, I would love to give this a try--unfortunately I don't.

[Sean Herron]

Heaven...

You peeps have re-lit my fire - so nice to see so much mental activity where it is so difficult to apply it - the small scale - built around a full size human form - power - speed - upwind performance - beach ability, discussions - AHHH - so it's not all about prostituting myself to the 'Who Wants to be a Millionaire' winners...

Many thanks - I almost bought a McDonalds franchise - now I will fight on...

SH.

[Nate]

In response to Matthews Comment... "If anyone can figure out a dipping lug system that is comparable in tacking time and ease, to the bermudan, then lets have it! "

I've been wondering if the following rig has been tried:
The sail, yard, and boom would be the usual size and shape. The traditional mast would be replaced with an A-frame type. The sides of the A would be attached near the gunwales, and the the yard would hoist up into the vertex of the A. The sail would be free to tack inside the A, and could rotate nearly 90 degrees for downwind sailing.

The mast could be bowed out slightly to clear the sail. The yard wouldn't be hoisted up tight into the vertex, allowing it to rotate. It may seem like the yard could jam & break if the sheet were eased too far. I don't think that would be a problem if the mast sections were connected but free to twist at the top.

[CT 249]

Re Matthew's comment "Becuase she is a double ender, she has no planing ability, but may give racing boats a run for their money when the wind is light and they can't plane)."

Is the fact that she's a double ender a problem, per se? International Canoes (pictured), the Swedish cruising canoes, the German Taifun cruising canoes, and Norfolk Punts are all double ended and they all plane. The Moths are basically double ended and can blow off a Flying Dutchman down a fast reach.

Lovely looking boat, by the way.




really if you are just after a cruising dinght grab and old FD,505 or light weight sharpie and reduce the rig by 30%. give it a little keet if you wish then roberts your fathers brother.

Ya, at a recent regatta a guy turned up with a Lightweight Sharpie (light version of the old 12 sq m Sharpie but with a 190lb hull instead of the 510 lb traditional hull) with a rig about 100 ft2 and an alloy centreboard. It was fast, stable and cheap. A Flying Dutchman is also incredibly stable and with a cut-down rig would be a placid machine; it was designed from the outset to be a cruiser/racer and live on moorings. You can easily stand on the gunwale of an FD without rolling it, even with the normal centreboard.

Down in South Australia, there are classes of "Tagis" and "Usual 20s", which are based on the Flying Dutchmen and Sharpie respectively. They just have a bit more freeboard and little cabins with bunks etc. They just show what you can do with these old racing boats in the cruising role.

[Bob Ames]

http://www.bana.com/nomad/support/onnewanderwal_015C39~3.JPG
Self promotion aside, your requirements sounds similar to the Vanguard Nomad.
Nomad at Bob Ames NA (here) (http://www.bana.com/nomad)
Designer's Comments (here) (http://www.bana.com/nomad/support/designerscomments.pdf)

[Doug Lord]

This was a great thread a while ago. The Nomad and this boat-among others-really caught my attention. Has any body run into any new variations on the theme in the last few years?
Colson 5
Address:http://www.colsonyachtdesign.com/designs/TrailerSailer55.htm

[Claus Riepe]

Doug,
since you asked,

'Matthew' has since designed and built some new boats that have been successful in Raid races, and especially in tough conditions.
For them, he has gone away from his previous double-ender design.

These discussions here do bear tangible results, sometimes.