just a question for all sailors

hey all
my friends and i have been tossing ideas around. we are now building 3rs. now this question is for all sailors that are in the water. what do you think makes your boat FAST, i was looking at my seawind. high sail area , low drag hull. and the boat accerlerates very fast. top speed is not that great. but still respectable. i looked at IOM 4 of them. and all have a higher sail area than the seawind. and my seawind will work better in light winds. so the only IOM that does not fit any molded ideas is KITE. KITE works well in both lite airs and a good stiff breeze. pivots on a dime.
so what do you think? low drag hull? boayancy far back? a lite boat or a stiff boat? long or short? ie. lenght over all. victoria or a marblehead?
no wrong ideas here. this is a toss up question.
lets see where this takes us:zbeer:

The skipper!

Remember the story of the two hikers that come upon a bear. One hiker puts on his running shoes. The other says “are you crazy? You’ll never out run a bear”. The first replies " I don’t have to outrun the bear"

It does not matter which type of boat is faster. As you race in a class, all you have to do is beat the other guys.

Enough levity.

My answer is “it depends”. One boat cannot win at every condition. Design and equipment are about compromise.

In higher winds, the longer waterline , stiffer hull, and flatter sails will be faster.

In light air, minimum wetted surface and fuller sails are more important.

The question is “how many variables can you control”?

In an open class such as 10R, the sail area (the engine) is reduced as the waterline (speed potential) is increased. So the choice of hull design parameters is crucial. And if you pick a heavy air design and the regatta is light airs, you will be at a disadvantage.

In a more closed class, such as IOM, the length and sail area decisions are made for you. There are still wind range differences due to wetted surface and wave penetration/beam for different designs. Chose what fits your average sailing conditions.

In a one design, such as Soling 1m or Vic, the variables are further reduced to quality of construction, finish and choice of sail maker.

The skipper is the main factor. You choose the design, the rig, the sails, the equipment. (99 per cent of winning is preparation).

You build the boat as close to the tollerances as possible.

You sand and smooth the hull for the best finish and minimum drag.

You trim the sails and adjust the rigging.

Finnaly, you understand the weather, strategy, tactics, and the rules and sail the boat with a minimum of errors.

You will appear to have the fastest boat! You may not, but a couple of tacks at the right time on the shifts made the difference.

Until you meet another skipper who did even more preparation than you!:cool:

A very good question.

I think the most basic thing is power to weight ratio. Boats very seldom travel at a constant speed. In light weather the ability to accelerate with every puff is often more important than sheer constant speed (the result of low wetted surface). Upwind the same applies - acceleration after every encounter with a wave. Off the wind in strong wind the boat with a lot of power in relation to its weight will surf/plane sooner and/or faster.

Easy?

No. Among other things, the power produced by the rig is quite largely dependent on weight (stability) and gyradius (a function of weight distribution and a major determinant of pitching behaviour) so we start to go round in ever-decreasing circles.

Furthermore in many classes there is a direct rating trade off between sail area and displacement. This means that for such boats we can only say that they are fast relative to their rating.

One thing that has been consistent in yachts throughout history has been that stable periods of design generally see a gradual increase in both weight and sail area. The next breakthrough (Dorade, Highlander, Myth of Malham, Clarionet, Australia II, Tituscanby, Ganbare …) has always involved radically less displacement and sail area and often less length but equally has also involved a massive increase in power to weight ratio expressed as sail area and the ability to carry it.