How has technolgy changed sailing speed?

[water addict]

jump in monohull speeds, mid 90s:

maybe from finally abandoning the existing rating rules at the time? 1993-4 was the whitbread 60, that seemed to be a big step in re-thinking the overall package of monohull ocean boats from the ground up.

[CT 249]

Seems to me Water Addict is pretty much on the mark.

The Open 60 style started to evolve in the late '80s, as far as I know, with boats like Ecuriel d' Aquitaine and MSF. Volvo 60s arrived for the '93 WHitbread and Intrum Justicia promptly broke the monohull 24 hour record. And in 1993, fast IMS boats like the ILC 47s and Mumm 36s started to come out in numbers and boats of that style started to influence production boats.

[rayk]

Originally Posted by CT 249

For example using Love and War, we can look at the 2003 Sydney-Hobart, pretty much an all-weather race from memory. The 47' Love and War finished 8 hours behind the IMX 40 and Beneteau 40.7 across the line (but still finished a respectable 12th on IMS). So Love and War, 7 feet longer, was about 12% slower when she started at the same time, sailed well, and had similar conditions.

Just curious, but what were the respective Disp/Length ratios?

[rayk]

Originally Posted by water addict

jump in monohull speeds, mid 90s:

maybe from finally abandoning the existing rating rules at the time? 1993-4 was the whitbread 60, that seemed to be a big step in re-thinking the overall package of monohull ocean boats from the ground up.

I think the refinement was driven by the change from
weather prediction (risk=bulletproof, might have to work upwind)
to real time information (certainty=sporty, we can make this a downhill ride most of the way).

[CT 249]

Not necessarily. Even in a race like the Hobart, where it's accepted that you will probably spend a great deal of time going upwind no matter what, design has changed. And the Transpac boats have never spent much time going upwind, and they have changed.

Most of the new IMS/IRC race machines that emerged around that time were designed for short windward/leeward courses. Boats like the ILC Maxis were not designed with long races as a priority so they were not affected by a change in weather forecasting. Despite that, there was a change in design due to the new rules.

It may depend where you're coming from. To look at the RTW, there are few weather stations in the Southern Ocean and in the Whitbread in this period, boats were caught out by unforecast changes. But the race course itself had been changed for political and economic reasons and that meant more reaching and less beating and therefore boats designed more for downwind pace.


PS DLR of a Beneteau 40.7 is around 140, Love and War would be high 200s (similar boats are around 290).

[Vega]

Originally Posted by PI Design

Lighter and stiffer hulls due to the use of foam cores and carbon fibres.
Laminated sails replacing Dacron.
Increased stability allowing more power to be developed. Stability has increased through water/canting ballast becoming more commonplace, the use of beamier boats (Open 60 etc) and longer/deeper/heavier fin keels (which were not structurally feasible previously).

Rough, great thread.

PI, I agree with you.

On the Groupe Finot site there is a very good explanation, by Jean Marie, about why and how large transom boats are more efficient and where they are in disadvantage.

It is only available in French, but the pictures are self-explanatory and I will try to translate the more relevant part:

"This kind of hulls, give more stable boats, boats that can carry more sail with fresh wind, close to the wind and reaching.
With light winds and small and short waves it is a handicap to have a beamy and flat boat. That can be a disadvantage for racing inshore where those conditions are frequent.

But for an offshore boat it is a valuable solution, mainly for open boats and cruising boats that are not handicapped by class rules".

http://www.finot.com/general/index_ang.htm

[jim lee]

Over and over you see the problem of, how to define if one boat's faster than another. 24 hour run? Winward leeward racing? Off the wind? At the wind?

I remeber reading an article, don't remember where, about a group that started racing boats on a circle track. This was probibly early '90s? They'd lay out a big 'ol circle and see what boat could sail around it the fastest. I don't think you were allowed to sail inside the circle. The theory was that this would give a "better" measure of the all around performance of each boat.

Could your screaming reaching speed make up for your sluggish pointing ability? Or, since you could outrun everything to weather, did that outweigh the fact that off the wind you did very little better?

Mathematically, its seems to be a pretty good measure of the area of a boat's polar curve in a given windspeed. Which -seems- to be a pretty good measure of a boat's overall performace.

Single number ratings? When I look at a boat the first thing I check is the PHRF rating. "Is it a slug? Or can this thing really sail?" Seems like a pretty good single number value for boat performance. Thousands are beating up and avaraging out these numbers every day in all sorts off conditions.

As to the seakindlyness of a modern hull? It seems to me that the more modern a hull is, the lighter it is. And, the lighter it is, the bouncier it is. To get away from this trend is going to take a poweful bit of "out of the box thinking".

But the lighter it is many times means the more fun it is too..

-jim lee