Good boats w/ shoal draft keels?

SP, I was talking about a small rudder foil on the bottom of the rudder on a relatively light displacement boat as per the original description.
On the I-14 a much larger foil is used(approx.mid span on the rudder) that has an adjustable angle of incidence: postive(leading edge up) upwind in displacement or semi-planing conditions and slightly negative downwind and is used to, in the inventors own words," fool the water into thinking the boat is longer".
But for the purposes of Johns rudder performance the foil doesn't need to be nearly so large and can be set at 0° relative to the static wl.

[mattotoole]

Originally Posted by Paul B

I don't have my copy of Theory of Wing Sections with me, but basically the flow through the slot delays turbulent separation, if you are viewing the two elements as a whole. The 30% increase in efficiency is a recollection on my part from reading an example provided in the book. I don't recall the section, thickness, or angle of attack. I am sure that the keel in question is not operating under those conditions.

Solid Wing sails like those used on C-Class cats use slots to great advantage, especially at greater cambers, where separation happens readily.

I'm sure Tom Speer can give us all a greatly detailed description and mathematical model for this. I can't.

I want to clarify that I am not advocating the Tandem Keel as the best solution. I was simply giving anecdotal evidence as to the performance in a single regatta where I witnessed it in a semi-controlled situation. There were at least two other well sailed WL 24s with normal keels in the same races to compare with.

I understand the theory, at least superficially. The question is whether it works for keels in the real world, and/or whether current implementations are any good. It sounds to me like the WL 24 worked pretty well. I read a couple of reviews recently of an Etap (?) using this design. Reading between the lines of a typical magazine review it didn't seem too impressive. However, the idea is definately worth exploring.

[mattotoole]

Thanks to everyone for your replies. I've been busy this week so not following the discussion as much as I wanted. But I have plenty of food for thought now -- I'll check out the H28, the Capri, and the tandem design.

[mackid068]

I've heard good things about the West Wight Potter 19 (fully retractable keel).

[Gunboatdreamer]

Originally Posted by mattotoole

Have any of you sailed a shoal draft monohull that you thought was surprisingly good? By that I mean going upwind well, and not really compromised overall. And I'm thinking about mainstream production sailboats, with the typical keel designs -- simple shallow keels, Scheel keels, wing designs, etc. -- from small daysailors to trailersailors, and larger sailboats too. Which ones have you sailed that were surprisingly good? What do you think made them better than usual?

Hi Matt O'Toole & all of you shoal drafters out there. Apparently this is a really old thread...2342 days old!!!!

Anyhow, to reply to anyone interested in the subject @ present (August 2011), I have had recent amazing experience with Southerly yachts, built at Itchenor near Chichester, UK, by Northshore Yachts. Recommend anyone to Google Southerly Yachts and look up the technical stuff on their electro hydraulic lifting keel system. These boats can be beached safely and stand upright on their keel plate and twin rudders, just like any self-respecting cat.

They point really high and with self tacking jibs its a doddle to weave close to the wind off the bows and hold steady, without broaching in a swell. The weather helm is barely noticeable as there is always a full rudder biting deep and we have had no problem on autopilot as high as 17-20deg off the wind, into 21 knots on the nose and holding 6.4 knots. Southerly currently build boats from 32ft up to 67ft. I have recently been sailing a 38 with twin wheels. Superb strength, design, finish and balance. USA spec available.

We hope to be ordering the new 420 centre-cockpit with a central wheel and transom garage for deflated tender and diving kit. Probably going for inmast vertical battened main and self-tacking jib, with extra poled Parasail for those Trade wind runs across the Pond between new home port in Gibraltar and Grenada. Guess we'll be doing the ARC in 2012 and then to Australia in 2013. (Spec those heavy deck cleats for Panama!) AIS transponder, MOB alert and all the crucial safety kit. Will be allowing for one luxury gadget: fwd looking sonar with alarm, as will be short handed and don't want to hit a container or whale in the dark. LOL.

After a lot of experience with serious cruising catmarans, I am convinced Southerly make the only serious monohulls that are affordable and can get anywhere close in performance to a big cat, without an AeroRig. With keel down you get ocean racing draft. Its a train!

One exception is the brilliant one-off Mona Lisa, a 62ft steel Trintella by Van de Stadt...unbelieveable. (see www.yachtmonalisa.com) Talk about thinking of everything! 160 hp Yanmar, twin everything (radars, GPS, radio, fridges, chartplotters, independent autopilots, generators, tridata, etc.) lifting lead bulb keel (6ft draft up), twin rudders, pilothouse helm PLUS two external cockpit wheels as well, icebreaking heavily insulated aluminium hull 8mm below waterline and 6mm above, watertight compartments including engine room, double glazing and central heating radiators (Antarctica anyone!) But we don't have $899k for a unique ten year old custom built expedition yacht, even if it did cost c$2,7million to build.

Have to admit if we had $1.75 million, we'd be sorely tempted to buy the Gunboat 48 Hammer from Peter Johnstone (www.gunboat.com - brokerage tab). But we need to be sensible, mooring fees and all that. So we are going with the best monohull we can afford that we can run up a beach. Sorry Oyster! Guys, if you can get to the Southampton (UK) Boatshow in Sept the Southerly 47 is being launched. Wow! Check it out.

In conclusion, our boat will be named Blue Moon and registered in Gibraltar, dark blue hull, burgundy cockpit canvas. If you see us anywhere in the next few years, come aboard for a meal.

By the way,if you saw Distant Shores on cable and satellite it's a Southerly 42RST, the newly launched Distant Shores 2 is a Southerly 49.

May music play in your rigging. Sail the Seven Seas with the Four Winds.

[Harold Anderson]

I have a Victoria Eighteen. It is very good on all points of sail. The boat draws 2 feet with basically a modified full keel. It is narrow and very good in a blow. Harold

[peterchech]

I just purchased a 1981 hunter 25. 2'11" draft fixed keel. I don't have enough experience with the boat to weigh in, and there isn't much out there online. Anyone know about these boats? Good things or bad?

I have to say, you can pick one up for 3K in reasonable shape and there are lots of 'em for sale in my part of the world...

[michael pierzga]

Didnt read all the replies....but Ted Hood has long been held as a master at fast shoal draft sailing yachts. The yacht " Robin"

http://www.flickr.com/photos/larrymoran/4724102619/

[FAST FRED]

Herischoff felt that a draft of 1/7 the LWL did not require a centerboard on a sound cruising boat.

FF

[souljour2000]

McCurdy/Rhodes Seafarer 24 ...good sailing qualities and stiff and stable for a 24-footer. Good fiberglass lay-up. Not a huge production run...but several hundred at least...There are a few around. Good luck and have fun out there...!