Heavy sailboats : Can they point ?

Since I was a kid , I was taken by the miracle of the sight of a heavy sailboat , with all its keel and rigging, floating without any visible support in the transparent surface of the water, and by its incomprehensible ability to sail against the wind. Years passed by , but I am still in love with these two marvelous characteristics of sailboats.
Nowdays heavy (large D/L ratio) sailboats are out of fashion , and one of many reason given is that , regardless of small VMG , they can not point as well . Is that true ? Is there a reason why a heavy sailboat can not keep a close angle to windward ?

 

Who said a heavy boat can't point well. The Americas cup boats are very heavy and point very well. Pointing ability is principally a function of righting moment and rig efficiency as well a number of other factors like hull drag and foil performance.

 

But hull drag is big and foil efficiency is deteriorated because of reduced speed due to this drag , aren t they ?

 

Big boats carry big sails (If not created to some crummy "racing rule") and go upwind just fine.

The tiny fly weight boats are all for "racing" and seldome can offer anything in terms of comfort .

Remember that most "racing" boats are built to a Rule ,
which gives time to the "slower & crappier" boats .
So the racing designer will attempt to build the crappyest rating boat that can still sail marginally well.

Thats how races are won , by a boat that can actually "outsail" its rating.

UGH if you enjoy sailing , or cruising.
OF course lighter co$ts less to build , so the cookie cutters are Quick to claim their output is a "Cruiser -Racer". Doubble UGH.

Take a look at any of the early 1900 to 1950 boats in the larger size , and you will see real boats . Even the 50's and early 60's boats do well .

Any old J boat will foot to windward with the best of the modern "race" boats , when the sea getsa rough and your climbing 10 ft waves every few seconds.

Smooth water performance is best left to bathtub racers , where the chance of getting killed by the design (Fastnet ?) is far less.

FAST FRED

 

If heavy is to mean big displacement for length, as the question posed, then the hull drag is higher.

Dan

 

Yah - but... If the SA/D ratio is the same, the heavier boat will have enough sail to overcome that.

Steve

 

Fast Fred is correct in his posting. You have to separate rule driven racing boats and "more sensible" designs. If the rating systems really worked we could race anything, and then I suspect designs would alter drastically .

When considering performance the sea state must be taken into account. This adds to complexity to the picture.

In higher winds the heavier (by ratios) boat will often be able to sail faster upwind as her momentum carries her through the waves, however downwind she can't surf as the light boat will.

There are many factors which determine the pointing ability.
So its probably best to say that heavy boats can definately point as well as any boat if designed to do so, with all that implies.

 

Who said ACC boats are heavy?

D/L for an AC Class boat at the heavy and short ends of the rule would be about 85. Compare to J24 at about 120, Farr 40 OD at about 110, and Melges 24 at about 65.

Add crew weights to the boats. ACC boat goes to about 90, Melges 24 is about 95, Farr 40 OD 130, and J24 155.

Most of the last generation ACC boats are longer than the model used for this calculation, so even lower D/L. Next generation will be 1000kg lighter, so lower D/L as well.

For their length ACC boats are lighter than most modern "Sportboats" and almost every other type of racing sailboat.

Of course Open 60s are only half the D/L of an ACC boat, but they are special cases.

 

Some of the J Boats were not very seaworthy at all. They were simply the racing/rating freaks of their time. They cannot sail with the large modern raceboats of today. Not on any point of sail, not in any weather condition.

Fastnet was a long time ago. A lot of the problems were as much due to poor preparation and sailing skill as they were to the design of the boats. Boats very similar to the boats that had major problems continued racing throughout the entire event. Light weight was not the problem, most race boats today are half the D/L compared to the boats racing the Fastnet in '79 and race in all sorts of nasty conditions. Look at the Volvo Race boats, crews, and conditions.

By the way, the greatest loss of life in the recent Hobart tragedy was due to the problems of an old heavyweight boat.

 

it was an old boat, but it was not the only boat that had tragedies on it, and part of the reason it sank was because it was missing caulking out of the bow. ohh & the boat that came first on line honours in the 98 syd hob had extremely bad delamination, so it wasn't just the old boats that suffered.

 

Hi Steve,

I'd rather be on a heavy boat in a seaway.

On flattish water, the boat with the heavier D/L will not do as well if the SA/D ratio is kept the same because the drag of "a heavy sailboat with all its keel and rigging" will increase as a third order function, while the power developed by the rig will increase as a second order function.

You could have a high D/L boat with good pointing by having fair lines and a lot of ballast in a bulb, but I doubt those were the boats he is remembering.

Dan

 

Hi Dan
Is it fair to compare sailboats with the same SA/D ratio or with the same SA/L squared ratio ? The impression a sailboat gives to the viewer is similar if SA/L squared ratio , or the side view, is similar.

 

Can heavy boats point?

All else being equal (unlikely admittedly) then the faster you go then the lower you point because the apparent wind comes back, and one of the main factors that limits you going upwind is the angle of attack your rig will work at. So well designed heavy slow boats can in theory (and in practice too IME) point far higher than light fast boats. But that doesn't necessarilly men they'll have a better VMG.

 

By the end of the 1800', the Norvegians really needed boats that might be able to sail against winds in storms, because they could not install as many lifeboat stations on their coasts as the British or French. They developped the "Colin Archer" type cutters (very heavy...), which are probably even today the only sailboats boats capable of progressing upwind in a force 10 gale.
I didn' say they are very quick at that, but they do progress. Modern sailboats just go backwards in gales.

 

Do a Google on "Pete Goss" "Dinelli" "Rescue" and "Around Alone", and then come back and say that again