Pointy Angle Things and Real Heavy Stuff Man

To point or not to point, that is the question......well I have blogged before on the topic of getting your boat to point, but is it always a good idea?

Another thing, how many crew are actually optimal for your boat?

The two are inter-related you can say, or really bang up to each other in the equation of getting your boat to go that little faster than the one next to you, be that off a start line in a dinghy or over an ocean leg in a swing keel speed machine.

If sailing (keel)  boats didn't heel over then we could really just look at the principles of payload. Payload does a few negative things of course - it introduces more mass for the force of the sails to propel, and it introduces a degree more drag on both the hull, and some air drag by volume of those bodies above deck. It does a few positive things though, firstly if we did not want heeling as in a dinghy, we can move the ballast nicely about ie crew payload, to counteract the heeling forces. Also it helps the boat actually reduce the drag and reach design speed by achieving optimal water line- in displacement mode.

When planing, weight is a negative factor for firstly overcoming the bump in the drag curve, which means in reality climbing up the bow wave and releasing the quarter wave. Secondly it creates more drag and this may reduce the speed or make the boat fall off the plane quicker. In some boats of course an optimal amount of payload weight will secure a large and more stable planing area, or hold the darn thing stern down on the water so it doesn't cork screw out or nose dive. forward.

We could look at some equations here, but let us not do that!

Water line is crucial for all keel boats when heeling upwind, with most having quite a small latitude in which the hull is at maximum water line, and hence can be propelled to max displacement speed possible, while also providing righting lever which helps convert more sail power in to forward motion. However you have to go back to Tonne designs to find many boats which don't achieve a near full legnth waterline with even quite a light payload while heeled. Tonners had a LWL measure in there, which was cheated around a little by allowing the sugar-scoop stern to actually be in the water when 'larded' up on the rail. Some sports boats though are also quite critical to this these days, however any 22 -26 foot sports boat you choose to name, will almost definitely reach full water line with 3 large men on board! Once we have reached full length water line, upwind we cannot get any faster in terms of the hull being driven, however we can apply more power to get to that speed and that usually entails resisting more heel from either larger sails or sails sheeted-on more.

Now on a 35 foot boat a couple of hundred kilos extra above that waterline  will make a couple of centimeters difference max. This could be rather critical depending on the hull shape, introducing perhaps exponential drag or unwanted weather helm effects for example. Some boats particularly need to heel at an optimal amount in order to have best water length, like the venerable Hunter Sonata which seems to truck along with its gunwale in the water and its crews knees in the heavens.

Another big issue is that a lighter boat will accelerate quicker to its maximum achievable speed for its current water length - and in light winds for instance the amount of total power from the wind available may not equate to reaching hull speed anyway, while in heavy winds the forces on the sails have grown on the cube, and thus even reefed sails generate more power and heeling moment, and the boat will heel in a heavy gust quicker than it ever will accelerate when resolving the forces, such is a sail boat's wish.

Most boats have a minimum amount of skilled hands to maneuverer them also, relative to other boats in a fleet, there is a disadvantage in too few, and perhaps too many too.

So there is a balance between the following :

a) payload to power ratio
b) achieving optimal water line
c) not introducing more drag on the hull than we gain in resisting more heeling moment on the rail
d) Accelerating and decelerating
e) Handling the boat

In a typical cruiser racer there will be a lot of general equipment which is not needed for the average, inshore race. When we took a sigma 33 to the nationals at Cork Week in 1996, there was a container hired for the class and I bet we had the biggest deposit going. We were down to minimum class stipulated stuff, and probably a deal less water and diesel to be honest given we had done a good few hundred nautical to get there from the Clyde. Our 'boatswain' and erstwhile coach, reckons we took over a metric tonne off the boat, and our water line was around the same we noticed, as the top competitive boats, mostly also from the Clyde at that time, like Phoenix, St.Joan and Vendeval. For once, our midfleeter was at the heels of the best boats going in a fleet of 77.

Another weary lesson the Sigma 33 fleet and probably a good few other fleets too, don't ever seem to learn, is that being over-sailed messes up both your optimal water line and the 'bite' of the keel. The fleet all look at each other and want to be smothered in the gusts and powered right in the lulls, and hence tool up with number 1 genoas, rated for 18knts true, and go sail in 22knts gusting 26. The thing is if everyone does this, then all the boats heel over and make lots of leeway in the gusts, and everyone then settles down to seemingly break neck speed in the lulls again. The Sobstad Genesis No. 2 was the least used sail in the wardrobe due to this effect, that actually blowing top of 5, 24 knots true, is enough for a working jib while in fact 16 to 22 knts true works nicely with a powered up #2 (a small genoa in this boat)

As the wind increases the forces go up by the cube so there is 8 times more 'pressure' every time you go up 2 knts of the puffy stuff. You notice this most on days in fact when the wind is very broken up, and the lulls are just enough to drive the boat, or around the top of force 5 upwards when the inshore gusts get really very violent. The boat heels suddenly a heck of a lot more than it has in the lull, and often catches you by surprise if you aren't looking up on the water "above" you. It goes off sometimes on an heel like you have been hit by canon fire, and in effect your boat has done a good job in converting wind energy to heel energy.

Pointing to the Stars ?

In a fleet as mentioned above, there is a kind of flock behaviour - if everyone as above, is oversailed, then no one dares be first to believe their instruments on the TWS. Also if everyone is pointing high and in the 'high groove' then you must follow suit it seems, in order not to get smothered by windward boat shadow, or start getting luffed by irate leeward boaters, especially coming off the start line. However this is often a case of the blind leading the blind- Trust several things and experiment is my advice.

For instance I sailed an otherwise unremarkable hunter 707 over on the Firth of Forth as crew for a season. We often sailed three up, in fact most often, and the owner liked that in fact. We were up at about 300 kg it has to be said all up. The boat had to be sailed with a lot more twist upwind in any weight of it. However we never lost touch with the fleet and more over, we often came over the infamous tide and current there quicker and got ourselves going fast in the shadow of the bridge pillars and banks. When we 'turned the corner' and got the spinnaker up, we left a lot of other boats standing while they caffaffled about who was pulling what and where the weight needed to be, we were planing and standing on the transom enjoying 14 knts boat speed.  Also a very well sailed j29 over on the west coast used to perform as well on wednesday nights when she was light crewed. They relaxed, took in a reef and footed off a little.

The fact is though that not all boats have a 'low fast groove', however you would be surprised how many do, below 44' bow to wind angle, and how many benefit from being sailed lighter, lower and much faster. Low and fast has also the advantage of eeking out even more acceleration in pure forward motion in unstable conditions. Big, old displacement boats may not benefit from this approach per se, but as in the example above, there is a deal of psychology in what best-pointing for VMG in a fleet actually is, and discretion when the wind is up, is often the better form of valour.

How to Get There ?

Knowing the characteristics of your boat is key here. What was the intended net and gross weight for sailing? What crew on rail ballast was envisaged ? How do you see when the optimal waterline and heel is achieved? What is the design wind for the boat with its design payload? ( the wind speed where the sail area is optimal for speed and pointing up wind, beyond which you begin to de-power the sails and rig) Some boats have no such data available now and perhaps class chairmen keep them closely guarded secrets, locked away from the internet's hoi palloi, other naval architects will be glad to send a table of these details over.

It is worth experimenting with if you sail in a one design fleet, but more so then if you can sail alone or with a canny comrade who can keep schtuhm, to go out with a good GPS set up and define what your leeway is, COG and SOG, thus VMG actually are to see if there are chinks in the armour in the above equation.

In fleet racing then also, given that you have a fast start and space to bear away a little, see how your VMG fairs sailing lower than you usually would. You may find the boat makes markedly less leeway, and hence the high looking bows or other boats are irrelevant.

All fleets evolve from the first day a couple of OD boats or similar designs sail against each other. Some of this evolution is to do with what is best out of the physical characteristics and performance parameters of the boat, while others can be just plain old flock behaviour. Those who find a key to break ahead of the fleet by a little neck length, then move the fleet into a new evolution.