Heavy sailboats : Can they point ?

[xarax]

Almost everybody agrees that a heavy sailboat can sail close to windward in a seaway . So , if safety matters as much as speed , why nobody sells or buys NEW heavy sailboats anymore ? Any real customers out there ? Do I have to suppose that the true believers are not so YOUNG anymore to buy a sailboat ? ARE WE ALL SO OLD ?

[SailDesign]

So , if safety matters as much as speed

In many cases, safety IS speed. Lee shores, f'rinstance.

The efficiency of the keel is what makes a boat point well.

High aspect ratio and decent airfoil shape make it point well.

http://www.vacantisw.com/keel%20design.htm

[FAST FRED]

Weight costs MONEY
(well at least currency) here in the US where REAL Money was outlawed since the 30's.

More weight does not handycap the boat and usually makes for a more comfortable & safer passagemaker.
Sure larger sails are required than on a flyweight , but a real offshore cruiser will have a far larger sail plan than a "racer" anyway.

For cruising with much comfort large food and fuel and water weights must be contemplated, somthing the stock cookie boats (unless of very LARGE size) can not do.

The DL ratio will be far higher (heavier boat) to be able to carry the weight, even when the LOA is the same.

Reason there are few real cruisers ? NO MARKET , the boats cost far more to create and would be of interest to so few , not many could be reliably sold.

With the price drop due to computer and automation , you might consider an aluminum vessel , custom built , if you need a real Cape Horn vessel.

FAST FRED

[Jason S]

Originally Posted by Mark 42

The efficiency of the keel is what makes a boat point well.

High aspect ratio and decent airfoil shape make it point well.

Wrong....

A high aspect ratio foil is not the answer to making a boat point well. It depends on your sailing sideforce.

A high aspect ratio foil has a high drag at no sailing sideforce compared to a low aspect ratio foil. But a high aspect ratio is better at producing lift for less drag.

Consider a cruising yacht at low sailing sideforce it is not advantageous to use a high aspect ratio foil until such a time that the initial drag penalty is overcome.

Look at the attached plot of drag versus sailing sideforce squared. The units are not of any significance.

I you have a cruising yacht your sailing sideforce may be down at 3 for example. It is clear that for this sailing sideforce it is better to use the low aspect ratio foil as this has lower drag. For an AC boat up at 9 for example it is better to use a high aspect ratio foil with winglets and any other device to increase your lift to drag efficiency because the initial drag penalty is quickly overcome.

I hope this makes sense.

[SeaDrive]

Originally Posted by Jason S

Consider a cruising yacht at low sailing sideforce it is not advantageous to use a high aspect ratio foil until such a time that the initial drag penalty is overcome.

I question your analysis (though not necessarily your conclusion). It seems to me that in heavy weather, with a lot of wind trying to push the boat to leeward, you will need a lot of sideforce. On the other hand, you may need it at a fairly low speed which suggests a keel with a lot of area.

The lines in your graph can be adjusted up or down to suit, by changing the size of the keel.

[SailDesign]

Originally Posted by FAST FRED

Weight costs MONEY

Bzzzzzzzt!!
Lightness costs money. Just ask any custom builder which is cheaper to build - a heavy cruising boat, or a super-light racer. Leave out all equipment and interior, just the shell, and the lighter boat is more expensive.
Steve

[xarax]

You can buy a 4by4 SUV to climb the mountains and cross the deserts , you can buy a street car that flies with 250 klm/hr , you can buy a motorboat that shakes your spinal cord with 100 miles/hr. Why on earth you can not buy a sailboat that can sail upwind in a seaway with some safety ?

[Stephen Ditmore]

I look at the question as long vs short, not light versus heavy. If you take a heavy design and double the station spacing you have a light boat (relative to its new, longer length). The question is, where is the optimum ratio of stability to length when the wind pipes up...

On the role of the keel, aspect ratio is always good, but slow boats need more keel area than fast ones.

[Sailorman]

In answer to the original question - NO. Traditionally designed, wide, heavy boats do not point as well as long, skinny boats. No ifs, ands or buts about it. However, as sailing is more about getting there than actually arriving, so what if they can't point as well. If you're in a rush, try a power boat.

[xarax]

Dear Sailorman,
I wholeheartedly agree with your conclusion. However, when I am talking of a << heavy sailboat >> it is more the shape of the immersed midsection (without the keel it is almost semicircular) that comes to my mind and not the width alone. Modern and super light sailboats are often wider than the old and heavy, but I am not convinced yet by any argument that a modern heavy sailboat couldn’t t point as well as a light one, if it is designed for that purpose.

[Lda]

I think that the idea that oder heavy boats couldn't point as well as modern plastic toys is just ridiculous and mainly relates to cheap marketing of modern toy factories.
If you consider heavy boat that were built with this point as part of their requirements (and you exclude most fishermen, cargos, tugboats, earthmovers...) you will understand that the capability to point was crutial for privateers and smuglers since a very long time, and important for yachtmen since at least the 1840.
But you also need to consider the progesses in materials, and especially the huge progesses in sailcloth since 1840. So I guess you have roughly 3 time-areas
1) Pre-1930 (mostly gaff-rigged boats) : heavy sailboats like French or British pilot cutter did point quite well. Those boat are supposed to have progressed, say, between the 1870 and the 1920 (that is real progresses, not rule-induced evolutions...). But you may also remember that the winner of the 1928 Fastnet race (ex French pilot cutter "Jolie Brise") was a near copy of 1871 French pilot cutter "Cours Après" (that is: it won a whole 57 years after it was designed...). I guess Jolie Brise would not have won with 1871-type sailcloth.
2) 1930-1955 (mostly heavy bermudian) : racing boat of that time (#late Fifes...) are excellent pointers. Every guys who had the opportunity to steer any of them will tel you that you generally get better angles windwards than with modern light boats. Those boats, being heavier, are generally slower than modern boats, and better angles doesn't necessary means better VMG. Also, I guess they fare much better with modern dacron sails than with original 1930' cotton sails.
3) from mid 1950' ("modern boats"), I guess they point better than 1870' boat because, with modern sailcloth, bermudian rigs give better aerodynamics than gaff rig for windward courses. Bermudian rigs dit exist at least since the XVIIIth century and didn't bring any advantage before the late 20' (once more : due to the progresses of sailcloth in that time). Compared with heavy bermudian racing boat, they generally do not point as well as them but have (more or less...) better VMG in "normal" seas. In very rough seas or gales, they have a worse VMG, and sometimes are just unable to make any progress to windward. This is a potentialy dangerous shortcoming that quite a few earlier, and heavier, performance boats did not have.

[asathor]

Since there are too many variables, including personal preferenses and what kind of a hurry you are in - in additional to construction and design issues, lets try an analogy.

Heavy (god) boats are like an old (maybe a bit heavy) hunting dog. They point quite well and when they point it is because they have found something they can take you to. In other words even if they are somewhat slow they will get you to/in the game (VMG).

Light boats are like young hunting dogs. Their noses are real keen (points high) and they will get you there fast but if things get a little confusing they might switch track or if the weather is bad they may take you somewhere else entirely.

If you like excitement and don't mind a few misses the young dog will get you more game (buoyes) on a good day but in inclement weather the older dog will put food on the table!

Add up the vets bills and the training time you have invested in the old dog and the analogy still fits.

Hunters feel free to correct me if I am wrong.

Come to think of it: Roast Duck and a glass of wine would make this discussion flow smoother (unless someone brings up shoal keels and ask for the definition of a gunkhole).

[dan coyle]

At an anecdotal level, the sea literature is full of accounts of bluff boats having trouble pointing, hence the Panama canal.
Dan