Pocket cruising boats

Thanks Paul.
Taken info from her class Association at: http://www.ultimate24.org/4436.html here her basic parameters:

LOA = 7,45 m
Lwl = 6,45 m
Bmax = 2,6 m
Bwl = 2,13 m
Draught = 1,67 m
HD = 0,3 m (guessed)
Disp = 925 kg
Ballast = 340 kg
Sail area = 32,9 m2
Power = 6 HP (FB. guessed)


Displacement /Length Ratio D/L = 96,15
Sail Area /Disp. Ratio SA/D = 35,22
Power / Disp. Ratio 6*HP/D = 17,64
Hull speed HSPD = 6,16 Kn
Potential Maximum Speed PMS = 9,09 Kn (just an indicative of potential, so real speed may be higher)
Velocity Ratio VR = 1,47
Comfort Safety Factor CSF = 2,69
Motion Comfort Ratio MCR = 8,13
Screening Stability Value SSV = 55,58
Angle of Vanishing Stability AVS = 118,78 º

Roll Period T = 1,05 Sec
Roll Acceleration Acc = 0,54 G's (Over 0.18 G is said to be intolerable)
Righting Arm 30º RA30 = 4,04 Ft


From here we can say (as is evident just having a look at the boat) that she is rather a weekend racer than a proper cruiser. Her very low MCR, in accordance with very low T and high Acc, indicates the boat as being quite uncorfortable (even unlivable!) for a long sailing in something more than almost flat waters.

On the other hand they state "minimal accomodation for four". Interior plans are not available, but I imagine an spartan interior with no headroom, so not really useful for long term cruising. Do you have more info on arrangement?

I may agree with you that fast may be safe, if you have the crew to properly handle the boat when in strong conditions, and not for a long period of time. I wouldn't like to experience a force 7 in this boat, even in a race.

Also, hinged rudders are not my favourite for when in rough weather for many hours, unless hings and rest of hardware is really strong (= heavy = not good for racing purposes).

 

data for uffa's 30 square (Estimating HD as 0.6):

Displacement /Length Ratio D/L = 116,48
Sail Area /Disp. Ratio SA/D = 15,53
Hull speed HSPD = 7,16 Kn
Potential Maximum Speed PMS = 7,79 Kn
Velocity Ratio VR = 1,09
Comfort Safety Factor CSF = 1,66
Motion Comfort Ratio MCR = 19,09
Screening Stability Value SSV = 22,44
Angle of Vanishing Stability AVS = 142,17 º

Roll Period T = 2,81 Sec
Roll Acceleration Acc = 0,06 G's
Stability Index SI = 1,22

This indicates that, although conceived as a racing boat, Square 30 have much better 'cruising' characteristics than the Ultimate 24. Even though I wouldn't go for extended cruising in this boat either. Uffa was a brave man....

http://www.uffafox.com/seaswall.htm
http://www.sskf.se/News letter/The30sInSouthAfrica.pdf

 

Another interesting boat: The Bristol Channel Cutter.
http://www.boats.com/boat-articles/Review-155/Hess's+Bristol+Channel+Cutter/1383.html

Wonderful mantra: "Go small, go simple, but go now!"

Displacement /Length Ratio D/L = 345,93
Sail Area /Disp. Ratio SA/D = 18,52
Power / Disp. Ratio 6*HP/D = 11,56
Hull speed HSPD = 6,87 Kn
Potential Maximum Speed PMS = 7,74 Kn
Velocity Ratio VR = 1,13
Comfort Safety Factor CSF = 1,67
Motion Comfort Ratio MCR = 36,96
Screening Stability Value SSV = 29,99
Angle of Vanishing Stability AVS = 130,01º

Roll Period T = 3,94 Sec
Roll Acceleration Acc = 0,05 G's
Stability Index SI = 1,28

 

Guillermo-

Cool thread.

Bob Perry reviewed the U24 in Sailing magazine, and you can see the interior there on line. By the way, the guy who owns Bijou II (a 30 sq) has told me that he likes the big stuff in her. Folkboat folk too.

We cruised our U20 (even smaller) a fair bit, even sailed in 55K (didn't mean to- thanks, NOAA & USWS) twice, in waves/chop before the waves got blown into spindrift of between 6-12 feet (outside). Once the waves get big enough, the ride gets ok, even fun in a small, light, boat. The worst discomfort we ever had on her was 15-20K on the nose with a short 5 foot chop, but everyone under 36' was complaining that day, even the heavy boys. It's not that I'm argueing for light boats in principle, but for strong, able boats that can get out of their own way and take care of you when it gets epic. Our U20 Rave, was knocked down 3-4 times in the above mentioned (55K) bad weather (Vertical Gusts from Above!), but always came up immediately, the mast only touched water if it went into the top of a wave, always handled predictably, aside from a small rip in the dacron main sustained no damage, and left me with complete confidence in her. It is really nice to plane out of a trough rather than stuffing the bow, stopping, wallowing in the valley, and struggling out. Even in the really steep stuff, she did not stuff- the bow went into the bottom of the wave, and 6 inches or so before the water came up to the deck, she would zip up and plane up and out. And this was without much control input- in fact, sometimes none. I think the ability of a boat to handle the lumps in the water is the mystery, and while I agree with your choice of numbers, I have been in boats with good numbers that sucked. It reminds me of L Francis Herreschoff's remarks about Admiral Taylor's theoretical view of the sea- something about waves coming in all shapes and sizes- even trochoidals flowing down his (L F's) neck! Everybody, in all sizes of boat, has stories of a gnarly waves and conditions. But that said, it's really interesting to see the numbers combined with sailing experiences on the boats. If it was up to me, we would test seagoing boats by dropping them from a crane from 20 feet in the air almost upside down with the crew inside, and expect to see the boat sail away immediately with no injuries. Kind of Lasers of the sea.

Paul

 

Thanks, Paul. Numbers are numbers and boats are boats. And a boat is even more than just an object, because boating has two major components: The boat and her crew. Anyhow the analizing of some simple parameters as the ones used (not always accurate, certainly) serve quite well to give us a rough idea of expected performance and focuse discussions. But then human factor comes into equations, and things begin to be more tricky. As you say, is interesting to see how parameters match with reality.

A well designed boat for a certain task handled by incompetent hands probably will collect more disasters than a inadequate one in good hands.
I agree with you that light boats may be safe even in rough conditions, as it's your own experience, and their buoyancy and planning ability may contribute to quicker run out of trouble.

But the question is with what amount of skills and punishment and applied for how much time. With experienced crews probably that's not a problem when in coastal cruising, because most of the times there is a shelter available in a matter of hours. Family cruising boats, on the other hand, have to be forgiving ones and should take care of her crews. Or even experienced crews when caught in dangerous waters with no shelter easily reachable. I'm not sure this is compatible with lightness. Would like to hear more opinions and experiences about this.

 

Guillermo-

I should add that the 55K sail was done under main alone & downwind- I'm more comfortable with an una rig in wild surrounds. Our 45-50K sail was done 80% under jib alone, 60% downwind, in a bigger seastate, and was so easy that we were making tea & soup. I got the speed of our U20 so we were overtaking the waves by 2-3 knots by furling/unfurling the jib, so I could pick our way through the troughs and stay away from the breaking stuff. We passed a number of boats, as we were doing 15K or so, one was some sort of mid 20' bristol cutter going downwind that was having a hell of a time with overtaking waves, one was a 30' double ender under 3 reefed main and storm jib running that was enjoying things like we were. Although it took them 3 times the time it took us to get to shelter. I was steering for 8 hours. I was a bit hammered, but alert and functional. We had a friend out in all this in his North Sea Trawler who looks for this kind of weather, because he claims that it's the only time his boat is powered up. (!) Got to go out with him sometime in big conditions. A 105' schooner hogged on a wave upwind, cracked some timbers. I must admit I like small strong light boats, personal preference, and the more I'm around, the more I like them in big weather. They seem to be able to take more. And I'm not sure their motion has to be so bad. The Ultimate20, for example, has a draft of 5' (keel bulb), and a ballast/disp ratio of mid/high 40%, which would put it in Rousmanarie's (hope I spelled that right) heavy weather safe vanishing degrees of stability ballpark. And I would agree, since she came up from the mast head in the water with me sitting on the high hull side and my wife standing on the downside cockpit seat side! Never did get get her broadside to a breaking wave over 5' though. But she was fine in 5' breaking waves broadside. And Antrim did the U24 too, as well as the Antrim 27, which has done the Transpac a number of times, which is why I brought up the U24. This said, I agree; ability, all round, matters. I think if you can surf ok and sail a Laser in 30K well, big weather can be fun (or safe) in almost any competent saiboat.

Paul

 

I thought you might want to have a look at this new addition: the Etap 28s.
This is quite an interesting thread!
Frede

 

Paul,
Thanks for sharing your experiences. This is most important to me, as I have had not the opportunity of sailing every type of boat, of course, so it's nice to be able to compare what numbers say with real experiences.

As I said, I agree with you that a fast sailing boat in skilled hands can be as safe, or even safer, than a salty heavyweighter. But skill is the name of the game. As you said: "....if you can surf ok and sail a Laser in 30K well, big weather can be fun (or safe) in almost any competent saiboat" And I would dare to add that for a long run you need a full skilled crew. I'm not talking about 8 hours steering, but, let's say, three days or more.

Let's say you are crossing the Gulf of Biscay with your family, from La Coruña to Lymington, summertime, not that bad weather report, and you're in the middle of it when you get caught in an unexpected Force 9 gusting 10 with 5 m waves. This is not uncommon and has happened many times. One I remember was when one of the last Transpacs, with the result of some days of busy activity for the salvage services and a handful of boats lost. I think it was 4-5 years ago, I'm not sure....

frede: I will review the Etap 28s later, as my Google doesn't want to work this morning (Bad sleeping...?). Thanks.

 

Guillermo-

I don't know know if I'd cross the Gulf of Biscay in anything short of Mari Cha III- Much much better sailors than I have come to grief there- from minis to 60' tris. Horses for Courses! How about a nice well balanced ketch? Or Romilly??

Paul

 

Here data for the Etap 28s, 1,68 m draught version as per data at: http://www.woodrolfe.com/etap28s.htm

(Note: HD = 0,5 m assumed. Sail area: Main + tacking jib)

Displacement /Length Ratio D/L = 164,11
Sail Area /Disp. Ratio SA/D = 17,82
Power / Disp. Ratio 6*HP/D = 14,55
Hull speed HSPD = 7,06 Kn
Potential Maximum Speed PMS = 7,98Kn
Velocity Ratio VR = 1,13
Capsize Safety Factor CSF = 2,22
Motion Comfort Ratio MCR = 17,62
Screening Stability Value SSV = 74,74
Angle of Vanishing Stability AVS = 116,18º

Roll Period T = 2,02 Sec
Roll Acceleration Acc = 0,21 G's
Stability Index SI = 0,6

(Note: The shallow draught version with tandem keel does not change significantly these numbers)

Roll acceleration Vs four physiological states: Imperceptible, Tolerable, Threshold of Malaise, and Intolerable. Malaise starts at .1 G, Intolerable begins at .18 G. G levels above .06 are considered undesirable for offshore cruising conditions.
Criteria for SI:
< 1.0 vessel considered "STIFF"
~ 1.1 vessel considered "IDEAL"
> 1.5 vessel considered "TENDER"

So this one is quite stiff having a high acceleration parameter and a very low MCR; this probably makes her uncomfortable when in open sea sailings. Design category B (Up to force 8 and 4 m waves) makes her suitable for short passages (theoretically). Under several european countries regulations, she will allowed to go up to 60 miles from a shelter. But if we look at her high 2,22 CSF, I'd rather say this is a boat conceived for club's regattas and some light coastal summertime cruising in mind.

Due to her flat and wide sections astern, floatation probably is quite assimetric when heeled, thus creating a 'lively' weatherhelm when going upwind (?). In spite of her big Lwl (almost the same as LH) I do not find accomodation specially well solved. I think the transversal big berth astern will be a rather uncomfortable place to sleep, except when in marinas. Probably engine accesibility is ackward and forward V berth seems not lengthy enough....but maybe this is too much a guessing exercise. Just stop here...

 

Although lovely, "Romilly was conceived for estuary and coastal sailing" (from Nigel Iren's site), so... but following links..What about this 30' Burnett-Irens designed "Zinnia"?
http://www.burnettyachtdesign.co.uk/010zinnia.html
Isn't she pretty?

 

numbers...numbers…

Etaps are one of the best boats that the mass market has to offer.

They are known to be particularly seaworthy and comfortable for their size.

Last year or so, Hans Habeck his wife Carola and their small child have finished a three year circumnavigation in an Etap 21i.

They had experienced no problem at all (and as it would be expected, they have experienced some bad weather).

I agree it is not a kind of boat suited for that, I mean 21ft, but the fact that they had made it without any problem says a lot about the seaworthiness of Etaps.

 

And about the seamanship of the Habecks...!

Etap 21i: http://www.etapyachting.com/index.cfm?Part=Yachts&YachtType=21i&Detail=TechnicalSpecs&Pos=1

 

In response to details of the yacht I spent 3 years sailing on she was a hard chined steel boat 25 ft x 9 ft, with a full keel strting at 0 at the bow and 4ft at the transom. I believe it was originally at cat rigged boat, but was set up as masthead cutter rig. The weight was 4 ton and up wind speed of only 5 knots with tacking angles of 100 degrees. Reaching and running was spectacular. The boat planed easily and would steer readily with a self made wind vane. The average speed for all passages over the years was 5.2 with a best run of 6.6 with twin genoas and no main with 20 knots from behind, this beat the previous best of 6.1 with the spinnaker and was much easier. Mast height was 30 ft with roller furling. Worst weather through Bass Straight was force 10+ down to 16 sq ft of main sail from behind with speedo off the clock down large swells. Boat was sailed with crew of 2 for 1 year and then single handed for 21/2 years. Sailed from Melbourne to Tasmania and then up the east coast to the Whitsundays. Had large double berth in bow and 2 settee berths. Engine was 12 hp two stroke petrol that gave 5 knots. What this is leading to is the boat was able to sail itself quite easily, would heave to beautifully and never looked like putting a foot wrong as the long keel could not broach. The biggest drawback was upwind abaility which is why we have gone for a boat with more keel, but more draft of 5 ft. If you are able to heave to comfortably and ride out any weather then you can sail where your heart desires. As we are on Phillip Island cruising is in Bass Straight, until we can work out how to retire, so we need to be able to handle the weather. I enclose photo of current boat, but do not have photo on file of previous. Regards Peter

 

Also about their craysiness...I mean doing that in a 21ft boat is already a litte bit mad, doing that with a one year child is rather irresponsible