What made Pilot Cutter so fast? Just rumors?

[Benz]

Originally Posted by NewAlexandria

Yes they say they are going 10 knots on any boat 28 to about 46 which I think is not possible. Then Southern Cross 31 would do it too, it's a smaller bow WestSail 32.

Can you cite who is saying this? I haven't heard these claims. You can't really overcome the laws of physics, and WL:speed is pretty well established.

As to the WS32 being identical in hull shape, well--to me a dirt bike is identical to a Honda Goldwing, but someone who knows about motorbikes could discourse at length on the differences.

I have a pilot cutter-design: a Cape George 31. While it shares with the WS32 the design aspect of a full keel, the similarities stop there. The bilges are far tighter on mine; the entry and exits are finer; the max beam is forward of midships but then tapers delicately aft, increasing with the tumblehome. Also, mine has no unsightly canoe stern, as though I were planning to do surf landings or sail backwards.
There is vast variety in what is called "Full keel," and there are more ways to do it wrong than right. If you stick with designers like Atkins (the WS32 isn't really his--that design's been hacked up, and most of his designs are great), Lyle Hess or Paul Gartside, you'll see lots of full keels done right.

[Kettlewell]

It depends on what you mean by "fast". Before powered vessels were common sailboats tended to have the ability to carry lots of sail, because most of the time there is not enough wind to push a boat to hull speed. Bristol Channel Pilot Cutters had long bowsprits, big gaffs, topsails, and could put up a lot of canvas while keeping the various pieces small enough to handle by a small crew. Therefore they could be sailed at optimum speed in light airs, making them "fast" compared to some craft. Colin Archer designs were oriented toward operating in offshore heavy weather conditions that required the ability to spend a lot of time hove-to in big seas. Speed in light air was not as valued, so they tended to have shorter rigs, often ketches, and the hull shape was very full and not as slim up forward. However, you'll note that back in the day the original CA designs carried a lot more canvas than modern versions, like Westsails. A lot of heavy boats today just can't carry enough canvas to maximize their speed, plus they are often towing a three-blade prop. I once owned a heavy Aage Nielsen double ender and I would consider her "fast" for her size, but she wouldn't beat a modern design. She would get up to a good 6-7 knots easily and just stay there, even in lighter winds, because she carried a lot of canvas and her weight would carry her through a chop without losing speed. We found that we comfortably made 150-mile offshore runs with no fuss. Not blazing speed, but comfortable speed.

[Fintry]

As noted in the article above, hull speed is a useful concept but by no means an absolute upper limit if the boat has enough power (sail or motor) to overcome it. Sweetwater, the Swan 57 on which we circumnavigated, has a 46 foot waterline. Our best 24 hours, on a broad reach between Bermuda and Providenciales, was 225 miles, averaging a little above her theoretical hull speed.


Jim

[pcmm]

Originally Posted by NewAlexandria

I"m looking at WestSail32 let's say, and I'm looking at Pilot Cutters from Bristal, and I don't see the speed difference in the design. It's basically the same boat. Physicals can't be overcome. There is optimal design for everything and anything close to it, will also be close to it in speed let's say. So how come WestSail32 is known for being slow and Pilot Cutters are known to be super fast. I don't buy it. The only difference is the rigging, but in that case most designers would simply select Gaff setup. What am I missing here?

You might want to take a look at their hull shapes. They are VERY different. the WS28 ( which is really the fair comparison) has a much shorter waterline, carries 200Sqrft less sail and has a very full hull shape, where the BCC has a more refined underbody.

compared to he WS32. they have similar sail area, but the BCC is 3 tones lighter, still has better hul shape and just as longt a waterline as the WS32

[Adelie]

Originally Posted by NewAlexandria

Maybe you guys are correct. I know nothing about boats, I only visually do not see much difference in hulls between Bristals, Southern Crosses, WS32s. I plugged in the numbers into calculator and for the most optimal scenario 44 water line is 8.8 knots. So Maybe. You could call them 9 knot boats. Maybe I'm wrong.

Where’d you get 45’ LWL for a WS32? Length Over all (LOA) including sprits might be close to 44’.

[Bowdrie]

Originally Posted by Benz

If you stick with designers like Atkins (the WS32 isn't really his--that design's been hacked up,

I wouldn't go so far as to say that design was "hacked up".
"Back in the day", I had several conversations with Bill Crealock, he didn't do anything more than several other designers, (Bill Garden comes to mind,) did in order to adapt a design drawn for wooden construction into something that could be lifted out of a mold.
Primarily, what would be the transition area between garboard and keel would be given additional thickness.
As a result, yes, some salient keel was lost but eddy making resistance was actually reduced.
Much of the drag on a W32 comes from the thick sternpost/rudder interface.
Those who have re-faired that area report a measurable speed increase.

Originally Posted by Kettlewell

However, you'll note that back in the day the original CA designs carried a lot more canvas than modern versions, like Westsails. A lot of heavy boats today just can't carry enough canvas to maximize their speed, plus they are often towing a three-blade prop.

True enough, one of the pictures I saw of a CA rescue boat showed a mainsail with 5 reef points.
Reefing down as needed so as to keep the boat "on station".
In the off season the crews would rig the topmasts and large jibs and race each other.
They could carry a lot of canvas, but with ~17' of beam on a 30-ton 47' boat they could carry working canvas in what most of us might consider as abysmal weather.

[TrentePieds]

No, you are not "wrong" :-)

But I do think you are confused. You seem to be trapped in some notion that advertised claims and published numbers represent some kind of "truth".

They most certainly do not!

You are lumping together disparate designs that were developed for different what I believe is in American parlance called "use cases" and attempting to find some commonality between them. Kettlewell (in #17) gave you a very good answer pointing out that the "use case" of the Colin Archer ("Redningsskjoite" - the "model" for the WS32) was in all respects very different from that of ANY pilot cutter anywhere.

In some respects, the redningsskjoite was "permanently reefed" i.e. had a LOW SA/D ratio, which is appropriate for the job she was designed for in the waters where she was to do her work. It would not be fair of us to expect you to know what those waters are like since it is unlikely that you have ever been there. Well, Colin Archer lived there :-)!

Someone else pointed out that the Lyle Hess BCC has a (design) SA/D of a little over 18, and for a modern cruising boat that is quite respectable. For a REAL pilot cutter of the late 18th century that was low indeed. Because pilot cutters were essentially "water taxies" and had to go "fast" to get any business at all, they were rigged so that the NOMINAL SA/D was 23 or 24. That meant that in almost all weathers they were "overpressed" and had to reef. They often had FOUR reefs in their mains and wore correspondingly small headsails so their ACTUAL SA/D when underway was 10 or 11.

Now, here in the Salish Sea, I often, in the winter, have to reef my puny 30-footer which has a NOMINAL SA/D of 14. On many a summer afternoon I wish my SA/D were 26 :-)

You also need to remember that skippers of redningsskjoiter (rescue vessels) had no choice but to go to weather since their course from harbour to sea ALWAYS lay into the wind. We Sunday-sailors don't beat to weather in any kind of serious wind if we can help it :-)! Skippers of pilot cutters also had to beat to weather whether they liked it or not. That affected the design of sail plan, the spars and the "rags". Neither materials economically available at the time, nor the technology of the time, permitted the use of lofty Bermudian rigs for vessels having the "use cases" of the redningsskjoite or the pilot cutter, although it was well known at the time that the Bermudian rig permitted a vessel to sail "higher" in the wind than a gaff rig could. The practical choice facing shipbuilders was therefore made in favour of the gaff rig. Sturdier, easier to handle for the uneducated.

Anyway, I recommended Beiser's book to you because it will cut through the murk of spurious accuracy for you :-)!

You yourself speak of wanting to design a "perfect" boat. A laudable objective, but you need to begin by defining your "use case".

Cheers,

TrentePieds

[NewAlexandria]

I'm glad I asked. Very educational for me. Thanks all.

[Christian W.]

I had a beautiful wooden Lyle Hess 24' sister-ship to 'Serrafyn', then moved to a cutter-rigged 32' steel double ender. Sailing side by side the Lyle Hess leaves me for dead.

[Adelie]

Nominal SA/D is a good way to predict light & moderate air speed relative to a similar size and length boat.

If SA/D is low, it doesn’t matter how good your light air sails are or what the largest percentage headsail you have is, at the point you are sheeting to the aft corner of the vessel you really can’t add sail area. A vessel with a taller mast and/or longer overhangs/sprits with the same displacement can set significantly more sail area and almost certainly go faster.

LWL is a good predictor of heavy weather speed. Once you hit hull speed more sail area isn’t going to make a significant difference unless the boat can plane which involves a number of compromises that are antithetical to comfort and safety on a shorthanded vessel.

Yeah there are various things that can be done to improve the speed of a non-planing hull but the effects are modest compared to SA/D & LWL.

On pilot vessels of old cost constrained hull length, sprits & and bumpkins were much cheaper than extending the hull.

[rslifkin]

To add to the points above, when people talk about a given sailboat being "fast", that doesn't refer just to top speed. Typically it refers to how easily it will sail to near hull speed, and how little wind it needs to do it.

[Kettlewell]

To add to the points above, when people talk about a given sailboat being "fast", that doesn't refer just to top speed. Typically it refers to how easily it will sail to near hull speed, and how little wind it needs to do it.

Great comment! I've owned various sailboats that had low top-end speeds, but still sailed faster than many in the typical light conditions many of us sail in. For example, in our Cal 20 we used to pass many a cruising sailboat on light-air days, but we would be flying a full spinnaker. Another point is that a lot depends on the type of sailing you are doing. Some boats are slugs off the wind, others are great to windward, some surf along above hull speed, and still others require 20 knots just to move.

[Cheechako]

Originally Posted by NewAlexandria

I"m looking at WestSail32 let's say, and I'm looking at Pilot Cutters from Bristal, and I don't see the speed difference in the design. It's basically the same boat. Physicals can't be overcome. There is optimal design for everything and anything close to it, will also be close to it in speed let's say. So how come WestSail32 is known for being slow and Pilot Cutters are known to be super fast. I don't buy it. The only difference is the rigging, but in that case most designers would simply select Gaff setup. What am I missing here?

Channel cutters were narrower for their length. 1 ft narrower than a W32
Channel cutters had a longer % waterline compared with their on deck length.
Channel cutters had a big sail plan possible due to the long bowsprit. Although this could be done with a W32 also to some extent.
A W32 is generally 5k lbs heavier. with a higher ballast ratio on a similar waterline length.

W32's can be fast on a reach though. Given wind. And have won their division on long races which dont require work to weather.

A 22 Channel Cutter kept up with our old school 30 footer cruising in tandem. They usually beat us although the boats were closely matched when "racing" to a destination.

[NewAlexandria]

Help me with 1 more thing:

Those pilot cutters had that kind of weird looking tail. The overhang was super long while the water line was much shorter. Was that required in order to have bigger sails, which means longer boom on main? Hence long overhang in the back to fit the equipment. And in that case why not double ender?

[Adelie]

Long overhangs was a means to beat handicapping systems for sailboat racing long ago.
The boats were rated on waterline length, LWL, when upright at the dock.
Underway and heeling more hull length would immerse and the boat would be faster than expected from the rating rule.
Over the decades various ratings rules have resulted in a number of design choices which in general offered no extra speed compared to similar sized boats from different rules but won races depending on which handicapping system was in effect for a given race.
All lot of these design choices are now considered "Shippy" or Classic".

If you want a long discussion of this history read "Seaworthiness, the Forgotten Factor" BY CA Machaj.

Actual working pilot cutters from way back tended to have a short stern overhang and a short overhanging bow or even a plumb bow.

This maximized strength and speed; handicapping was not a consideration.