Kretshmer on 'Traditional' Boats - Floating Bathtub / False Security ?

[Robert G]

Thanks Gord, thanks Hiracer, for the links. Looking forward to clicking through and checking them all out...


R

[Brent Swain]

A lot of those older short keel with attached rudder boats can have their downwind control greatly enhanced by taking the rudder off the short keel and shipping another on a skeg at the stern, where a rudder belongs. I did that with my Pipe Dream and others have done it with other such designs. Albergs, and Spencers come to mind. The results have been great, and the change in balance , minimal..

[barnakiel]

BTW I forgot to send THX too.

Gord - THX for the link. Cool read.

b.

[Hiracer]

Originally Posted by barnakiel

It may be another urban legend.

In light airs the light boat beats the heavier one hands down.

No urban legend. I was speaking to a witness.

A boat's speed in light air is largely a function of how much power it has, specifically the SA/D ratio. After that, underwater surface area is important.

A full keel has more surface area than fin keels, which is a disadvantage in light airs, but if the boat has enough sail area it can compensate and even overcompensate for that disadvantage. This is exactly what the Pardeys do.

The only time a light boat beats a heavy boat in light airs is when (1) acceleration is important (e.g., out of tacks on a race course) AND the SA/D is the same, the latter rarely being the case. In fact, most heavy boats have lower SA/D ratios, which is largely why they are slower in light airs. It really has little to do with displacement.



Full keels have another disadvantage going to the windward, in that their foil is short. Most of the lift is on the leading edge, so a shorter leading edge means less lift. This is to be compared to a deep fin keel (and explains racing keels). But this performance difference between deep fin keels and long, shallow full keels comes into play in light and heavy air.

[barnakiel]

Yes. I understand the aero and hydro dynamics issues, but I have seen the Pardey's boat and it did not have anything out of a standard set of sails and then again the stick is a relatively short one. So, much as I share your view on SA vs. wetted area vs. speed potential, I do not see how they could do the trick with their boat.

If we assume their boat is similar to a BCC then the biggest sails will be the reacher and the main. Together, they will give some 10 sq m per 1000kg of displacement - very adequate, but nothing unusual. A Bavaria will have more SA per displ with a reacher. And Bavaria does have more efficient (less drag, more lift) hull and foils.

So, I say, if the Pardeys outsailed the newer, lighter designs, it is because they are better sailors, not because they had the better boat (for light wind racing). Put them in a Bavaria or Bene and again they will win against a Hess design sailed by the other skippers.

barnie

b.

[Hiracer]

In the design phase, Larry demanded that Hess change the rig to accomodate a longer than original bowsprit to give Larry the option of piling on sail in light airs.

Thus, the hull is similar to the BCC, but the rig has an important difference which provides a higher SA/D ratio than what Hess originally envisioned. Since Larry knew he would be sailing sans engine, he knew he needed the extra sail area. Ergo, the boat is better than expected in light airs.

So Larry knows what he was doing on the water and off.

[David M]

I can't think of any other object on this planet that is a compromise between more desirable and undesirable characteristics than a boat.

[s/v Beth]

I picked my V-40 largely on JK's recommendation, and I think he was right on. It has a sweet motion. I know speed and beauty and sails and everything else is important...but you can change the beauty of a boat and you can add sails, but there is not much you can do to change its motion (once it is built).
So it is different strokes for different folks. BTW- I think dark red hair is the most beautiful.

[roverhi]

Most people hire a delivery skipper because they don't want to make the sail themselves. Why don't they want to make the sail??? They don't want to sail to weather. That's the reason that Delivery Skippers put such a high value on windward ability becuase they are having to make the windward sails.

Westsails are not slow, it's just a lot of the sailors that sail them are slow. A Westsail 32 (Saraband) just placed 2nd overall in the 2010 light air Single Handed Transpace Race. Saraband crossed the finish line in the middle of the pack and ahead of supposedly much faster boats (Valiant 40, Cascade 36, Catalina 309, Islander 36, Express 27) and less than an hour later than a downwind flyer ULDB (Olson 34). Other Westsails have won major ocean races. Ours had several 24 hour runs over 175nm and averaged 118nm for more than 10,000 miles with hardly any engine time.

The W32 will not go to weather in light air and a chop. The very few times we encountered such conditions, we just ran the engine at a couple hundred rpm over idle, pointed at 30 degrees to the relative wind at 4knots or more. If we chose to sail, we just cracked off about 10 degrees and made good time though not pointing quite as high as the fin keel, go fast boats. The W32 will go to weather just fine in open ocean conditions. We had to beat into the Marquesas for 4 days. Averaged more than 5 knots in dry, relative comfort.

Perry's heavy displacement boats like the HC, etc. have finer ends and should be better windward boats in some conditions. Doubt they will be any faster, water line length for water line length than Westsail.

Two Westsails were abandoned and one certainly sank in this past years SoPac class. One mysteriously started talking on water, was abandoned and sank. The crew couldn't find the leak which was apparently quite bad. Could have been a broken hose, seacock, propellor shaft or what ever?? It wasn't weather related. As someone else has mentioned, the youngest factory boat is now nearly 30 years old. Small things that can turn into big problems are getting old and need to be renewed. The other W32 was abandoned after a dismasting. Something that can and does happen to a lot of other boats. Didn't say whether it was a wire, fitting, or chainplate failure. The outboard chain plates and wire are all sized very generously on a W32 but a failed shroud will almost always result in the loss of the stick. Why they didn't set up a jury rig and limp into port is anyone's guess.

A fin keel boat can have a lot of things going for it. You definitely want a long enough keel that the boat will take the ground without tipping on it's nose or driving the keel up through the hull. The rudder needs to be solidly attached, preferably wiht a skeg and a bottom gudgeon, and hull shape should be balanced so there are no handling quirks.

[barnakiel]

Originally Posted by Hiracer

In the design phase, Larry demanded that Hess change the rig to accomodate a longer than original bowsprit (...)

Thus, the hull is similar to the BCC, but the rig has an important difference which provides a higher SA/D ratio than what Hess originally envisioned. Since Larry knew he would be sailing sans engine, he knew he needed the extra sail area. Ergo, the boat is better than expected in light airs.

Perhaps.

Yet this source:

Lin and Larry Pardey's Boat Taleisin | YachtPals.com

quotes SA 740 and disp (light) 16400, 17800 loaded

while this source:

http://www.samlmorse.com/?a=bcc_specification

quotes SA 637 and disp (light?) 14000

So, as you can see the SA/DISPL ratio is the same and actually slightly better for the BCC. In the cruising mod (much as I distrust Pardey's claim to carry only 1400 of extra weight) the ratio will be even less, and, in fact, well below any modern cruising design.

The boat may be better than expected in light airs but will not be better than equally well sailed Bene, Bavaria and such likes.

And if they did outsail anybody in light airs, I will insist it was because they are good sailors NOT because their boat has better SA/DISPL than the other designs (because based on the data I could get from the net, it does not).

barnie

[Hiracer]

Originally Posted by barnakiel

So, as you can see the SA/DISPL ratio is the same and actually slightly better for the BCC.

I don't believe the stated displacement for the BCC one bit. The differential is simply too big to be believable. The glass boat is not that much lighter than the woodie, if at all.

Ergo, the SA/D ratios are not the same.

[Wotname]

Originally Posted by David M

I can't think of any other object on this planet that is a compromise between more desirable and undesirable characteristics than a boat.

Women?

[barnakiel]

Originally Posted by Hiracer

I don't believe the stated displacement for the BCC one bit. The differential is simply too big to be believable. The glass boat is not that much lighter than the woodie, if at all.

Ergo, the SA/D ratios are not the same.

You may base your opinions on what you believe.

I will base mine on what I can read in boat specs. And the specs say a new Bavaria has better SA/D than both BCC and the Talesin (if this is the boat's name). At the same time a Bavaria (generic name only) will have more efficient hull form, foils and less wetted surface = less drag.

As I said - I do not play down the possibility of Talesin sailing faster than other designs in light conditions - I simply see the possible explanation elsewhere.

I believe you may agree that the 1400 of cruising load as mentioned re Talesin is a likely story too. Again, not impossible, just highly improbable.

This much drift said, I want it to be clear that I would pick up a BCC before any modern cruising design for the type and range of cruising I was doing. Not only because of how the boat sails but also because I find it pretty.

b.

[Hiracer]

Originally Posted by barnakiel

You may base your opinions on what you believe.

I will base mine on what I can read in boat specs.

Published displacements for sailboats have proven to be notoriously inaccurate. Rely on them at your peril.

Given the differential in the two displacements, they are suspect IMO. It doesn't make sense for them to be so different. It makes more sense that the marketing department had a hand in the BCC numbers.

[Hiracer]

Originally Posted by barnakiel

I believe you may agree that the 1400 of cruising load as mentioned re Talesin is a likely story too. Again, not impossible, just highly improbable.

I agree that 1400 pounds is too light for total cruising load, but that sounds just about right to me for the difference between light and loaded cruising displacement.