Ideal average angle of heel 20-30ft LOA

Some other ways to achieve zero heel:

multihulls like the catamaran as already mentioned
movable ballast - including the crew in a small boat
a Bruce foil
an offset and inclined mast
the last 2 are sometimes combined (see SailRocket)
a kite sail

- and of course you can always hop into a dinghy and have a sailboat tow you along, or use an outboard

 

As I said above, if the hull and ballast are symmetric than the boat has to heel. Crew hiking out or on a trapeze are ballast which is not symmetric. A canting kell is also not symmetric.

Inclining the mast does not keep the boat from heeling. The distribution of ballast, live crew or a weighted keel or water or ..., is what can bring the boat back to zero heel angle.

 

A multihull heels.

An offset and inclined mast would have to be offset and inclined a great deal, much more than is feasible on any boat with anything resembling normal proportions.

Basic physics. The sails exert a force above the waterline which results in a moment about the centerline of the boat at the waterline which tends to heel the boat. An opposing moment is needed from the hull and/or ballast or the boat will capsize. A symmetric hull and symmetric ballast only exert a moment about the centerline of the boat at the waterline IF the boat is heeled.

 

For information, this small kayak sail rig was a demonstration model which combined an offset, inclined sail with a Bruce foil (an offset, inclined leeboard) to cancel heeling forces. The demonstration was successful: I don't have a photo of the later version with a larger sail. The offset and inclination of the sail and foil are, of course, interchangeable to a certain extent: the SailRocket is a more extreme example.

Back to the subject of the thread: other things being equal, heeling angle tends to be less on a larger boat. This is due to scaling. If you scale a design the righting moment varies as the 4th power of the linear dimension whereas the heeling force of the sail varies as the 3rd power. It explains the monumental sail areas carried by the 12 meter racing boats, as an example.

Larger boats tend to have more masts so their centers of effort are proportionately lower. As a result of all of these factors the heel angle on a large multimasted ship is typically no more than 10 degrees or so but a sailing dinghy in a race may spend much of its time on its ear. Many hulls are faster when heeled, despite the fact that sail thrust and hydrofoil efficiency are reduced.

Designers know the intended use of a boat when designing, hardly a surprise, and will design a cruiser with far less heel in mind than if designing an ocean racer. When designing my kayak sail kit I bore in mind that the kayak has poor stability and the cockpit is too tight a fit for me to move around to keep it upright in a breeze. It's all relative: Einstein would have loved designing boats . . .

 

Yes, but there must be something wrong. After delivery we did not hear very much about 'Maiden of HongKong'. The owner appears here regularly for racing - - - but with a different boat.

 

Well then, here is a challenge for the boat designers. My family has motion sickness, and they take normally a handful of "tricks" like a band around the wrist, plasters, pills, it appears that by heeling + movement it gets even worse. For that reason 0 heel. What more "tricks" for them to try out, are there available?
Bert

 

My humble apology Human 1.0, it was not my intention to make an abrupt end at your thread. However, as there is no medical section and motion sickness is very much associated with heeling, I trust that you accept my apology. It is funny, some 23 years ago my wife did her yachthand course in Durban and at that time she was able to get a Ciber Giga plaster (Swiss product) , which she could place behind her ear. It was during tornado time and the sea was quite wild. She was the only one (and her trainer) who did not have motion sickness and stood at the rudder while all the others, only men were as sick as a dog. It is a pity that the product has been taken of the market. That band around the wrist works, but so so . Pills does also work so so. Anybody any suggestions on what does work ? (Human 1.0 may I have your permission? )
Bert

 

The Dellenbaugh angle is the measure that the thread starter should read up.

Bert
My understanding is that motion sickness is mainly due to vertical acceleration. A stable angle of heel is not a significant factor. Extreme angles or violent rates of roll are a different matter.

 

Hi Mike,
I have had no motion sickness sofar, but like I have explained in #36, it is the combination of both , movement and heeling what apparently makes it worse for them. What is available in your country for this problem?
Bert

 

Bert I suspect the heeling in your families case simply adds to their stress which makes their mal de mare worse. There's not much you can do except to give them lots of psychological conditioning to ease their insecurity but you have to do that before they step aboard.

What sort of boat do you have?

 

We have always been renting the yachts, much easier to fly to a destination and rent there. I have a small inflatable with a 4 Hp, but that is just a toy. It is not that simple. Even driving in a car and taken a corner at a too high speed let those people who have motion sickness, makes them very sick. It makes even a difference as a front passenger or at the back. Also, not having had breakfast or very little adds also to the problem, No, it is not phychological, I wish that was true. They are brave enough to join me many times on the boat. But I can see if the yacht makes sudden movements, their balance is badly affected thereafter.
Bert

 

There's some infomation on rmotion sickness here and some suggestions here http://health.howstuffworks.com/men...nditions/how-to-deal-with-motion-sickness.htm

If it affects an entire familiy there may be a genetic connection or it may be made worse by association; maybe if they go out one at a time some of them may have better reactions.

It's different for every person, and it's helpful to figure out the triggering sensation. I thought I was immune to rmotion sickness since I happily sleep through storms on planes and rather enjoyed a stormy Atlantic crossing, then I tried reading in a moving car, when I got queazy. So I don't do that. There is a psychological connection IMHO, anything that can be done to provide a distraction or minimize fear should help; maybe give them something to do. Fear should not be confused with lack of courage BTW.

 

Thank you,
Never gave it a thought that it was taken off the market, while still available via a doctor. Your article was spot on and certainly valuable. Thanks. Indeed it is a genetic problem.
We will be cruising with the Norwegian Jade in July from Venice and unaware have choosen an inside cabin. Another tip from this article. Thanks so much.
Great help.
Bert