Wide Beam vs Narrow Beam

[wolfenzee]

Though my boat is pretty tight below decks if I kept the same lines and increased the size by 20% that would give me 36' LOA with a 10'6" beam...,which would allow lots of cabin space and still have the nice sleek fast lines she has.

[Srah 1953]

[QUOTE=Bash;550159]This argument seems to ignore the latest developments in offshore racers. Farr 40s, for example have a beam in excess of 13'. Box rule boats such as the Transpac 52 are invariably built to the maximum beam allowed (which in the case of the TP 52 is just over 14' 6".)

I don't know that these "extreme" racers are relevant to what represents acceptable practice to "normal" cruising folk who just want to get from A to B in some comfort and safety. The racers are professionals or semi-professionals who are willing to push themselves and their boats to the very limits.
The best analogy I can think of is that rally and racing cars get a complete engine and gearbox overhaul after EACH race. Their experience is completely irrelevant to what ordinary people drive every day.

[sneuman]

I consider crew fatigue to be a major enemy of seaworthiness ... easy motion, dryness, strength, windward ability, a comfortable deep cockpit, a safe interior and, above all, ease of handling and balance with or without steering aids. With a small crew, possibly no longer athletically endowed, these are what make for fast passages.” – Bill Crealock


when it comes to light v. heavy, broad v. narrow, fin v. full, I think observations such as Bill's are overlooked. A year or so ago, we had a thread comparing the speed of passage of the Carib 1500 cruising class and we discovered that many of the more traditional monohulls beat cats and more modern, lighter displacement monos (a Valiant 40 was first, as I recall).

I would attribute that to lots of mom-and-pop crews who, in the end, had no desire to push their obviously faster designs to their limits. Just saying.

[u4ea32]

Originally Posted by Bash

This argument seems to ignore the latest developments in offshore racers. Farr 40s, for example have a beam in excess of 13'. Box rule boats such as the Transpac 52 are invariably built to the maximum beam allowed (which in the case of the TP 52 is just over 14' 6".)

Narrow isn't fast. It's just narrow.

Race boat shape is never independent of the racing rules. All recent racing rules that use measurements (post 1965, not including arbitrary performance rules like PHRF that don't use measurements, just use observed performance) penalize narrow beam and underestimate the advantage of moveable ballast (crew on the rail). No exception. The box rules are the worst at this: TP52 and similar box rules don't measure stability at all, but have very light displacement. Therefore, one would expect to see, and one does see, racing boats that are wide.

Rowing shells have no measurement that involves restrictions on length or beam, only on power: e.g., 8 man boats. Such boats, carrying a total displacement including crew of about 2000 lbs, are about 55 feet long and 22 inches wide.

Narrow is fast. Wide is dramatically higher drag, and therefore requires dramatically more power to move at the same speed.

Wide boats can be fast just because they can carry more sail power. The fastest boats (high performance multihulls) sail on a very long and narrow leeward hull, with lots of beam and therefore stability. They work because they combine the long, narrow low drag hull form with tremendous stability.

A fat racing monohull combines the high drag beamy hull form, VERY light displacement to reduce the otherwise horrible wave drag of a fat hull, lots of weight on the windward rail, and very large sail plans. While it sorta works, its very expensive. And if its not very light (D/L < 100), its simply slow. Cruising boats never have very light displacement once they have all the gear, water, fuel, etc. on board.

A narrow monohull requires a deep heavy keel for stability, but the narrow hull allows much more displacement to be carried and still have very low wave drag. And the low drag requires less propulsive force, so smaller sails. Its a potentially cheap way to go.

That's why all freighters have length:beam ratios of 5:1 or better, and are usually closer to 10:1. Examples include the T1 supertankers, the largest in operation, are 380m by 68m or 5.6:1 and travel at 16.5 knots, or one third hull speed, so they are concerned about wetted surface and the cost of that surface area (steel) rather than wave drag. Yet they are still half the beam:length of a Farr 40.

In conclusion: rating rules and the shape of marina slips drive this fashion of very fat boats.

[cfarrar]

There's a reason that rowing shells are long and narrow. Same with multihulls. The 110 is also a cool design: 24' long, 18' waterline, 4.17' wide, and really fast for a small, non-planing monohull.

[Adelie]

Originally Posted by sneuman

I consider crew fatigue to be a major enemy of seaworthiness ... easy motion, dryness, strength, windward ability, a comfortable deep cockpit, a safe interior and, above all, ease of handling and balance with or without steering aids. With a small crew, possibly no longer athletically endowed, these are what make for fast passages.” – Bill Crealock

Where's the Crealock quote come from? Interested.

[slap]

Originally Posted by Adelie

Where's the Crealock quote come from? Interested.

It's about the Pacific Seacraft 37:

“The 37 was, throughout, aimed at those people who, while wanting a pleasant boat to sail locally, just might want one day a boat able to take them in safety to any part of the world; and this with as much speed and comfort as possible without detracting from seaworthiness. I consider crew fatigue to be a major enemy of seaworthiness, and this meant an easy motion, dryness, strength, windward ability, a comfortable deep cockpit, a safe interior and, above all, ease of handling and balance with or without steering aids. With a small crew, possibly no longer athletically endowed, these are what make for fast passages.” – Bill Crealock

[Adelie]

Originally Posted by slap

It's about the Pacific Seacraft 37:

“The 37 was, throughout, aimed at those people who, while wanting a pleasant boat to sail locally, just might want one day a boat able to take them in safety to any part of the world; and this with as much speed and comfort as possible without detracting from seaworthiness. I consider crew fatigue to be a major enemy of seaworthiness, and this meant an easy motion, dryness, strength, windward ability, a comfortable deep cockpit, a safe interior and, above all, ease of handling and balance with or without steering aids. With a small crew, possibly no longer athletically endowed, these are what make for fast passages.” – Bill Crealock

I was not clear, what publication and date was the quote from?

[Jim Mc]

flat water sailing.. flat bottom .

sea sailing vee bottom

[bob perry]

Here;s a 62'er we are buiding with very narrow beam. 9.86'

[hummingway]

Originally Posted by bob perry

Here;s a 62'er we are buiding with very narrow beam. 9.86'

I didn't see a 62 footer at your site. Was that the ICON?

[Bash]

Originally Posted by bob perry

Here;s a 62'er we are buiding with very narrow beam. 9.86'

Welcome back, Bob! Your absence has been noted, and you've been gone too long.

I will certainly grant you that narrow can be fun. For kayaks and shells it's also quite fast. But for my cruising kayak I've chosen a beamy Eddyline, built up there in Seattle. It's stable, it carries the weight better, and when I'm loaded down with a week's worth of coconuts, I have no trouble keeping up with the kids in the skinny yaks. They can never seem to figure out why they can't pull away from the old fart in the fat yak.

[bob perry]

Bash: I have two Mariner Kayaks and they too are a bit beamy but work nicely.
But this is apples and ornages. I was talking about medium to large sail boats, not kayaks.

[wolfenzee]

William Atkin in a description of one of his boats around 1950...

"....Boats are among the few things that today can be designed and built at a reasonable cost and still reflect and incorporate the exact requirements to provide individuality...."
ohh how things have changed.

What he said about mine was ".....I must say that in these days of intricate mechanical and social developments, simplicity, with all of its old-time charm, is well worth flirting with."
This explains why I chose an Atkin boat.

[bob perry]

Here is my skinny 62'er.