Tuesday, 24 January 2017 10:12

Boat Speed and Performance

By Karl Purdie, reprinted from Finn Masters Magazine 2014

Being a relative newcomer to the class I must admit to being surprised to have been asked to contribute my thoughts on how to sail a Finn fast. I am still learning so much. However I consider it an honour to be asked so for what they are worth here they are.

Boat speed
Boat speed first and foremost comes from being fit as long as your boat set up is in ‘the ballpark’. And as Masters, and after witnessing the boat park action at La Rochelle, I’m sure we are all pretty much in that ballpark. The fitter you are the harder you work the boat, the better you are able to concentrate and the faster you go. In my opinion a lot of people spend a lot of money on the very latest go fast gear for a very small gain in speed when for a fraction of that cost they could join a gym, work on their bodies (which after all also has added benefits outside of sailing) and make huge gains in speed.

That being said if everyone’s fitness is equal then I believe boat speed primarily comes from having the correct mast/sail combination, followed by having a good hull.

My gear selection
When I entered the class two years ago I wanted my gear to be competitive from the start. Consequently I purchased a new 2011 Devoti. I didn’t specify any construction details to Martin other than I wanted a hull suitable for a body weight of 95 kg. I leave the centreboard case stiffeners in as the boat just feels noticeably more lively to windward in moderate wind conditions then. Without them in I have found the boat to feel sluggish and actually be slower. He built me a great boat. The boat I used at La Rochelle was a 2003 Devoti hired from Jan, it didn’t leak a drop and was a fantastic boat. The guy who recently brought that for only EUR 4500 got the deal of the century.

My first mast was a C-Tech built from UHM carbon. I used C-Tech because they had built all my OK Dinghy masts and I felt there were some ideas from there that I could bring into the Finn. My sails were matching NZ North designs I had contributed to with Dan Bush. However once Josh Junior began sailing/training with me it became apparent this rig was not as fast as his Wilke/UK North configuration over the wind range, no matter how much I modified it. Consequently for the recent Masters worlds I purchased a new Concept mast and matching UK North sails from Luca. The Masters worlds were such a rush I never had the time to tune the rig correctly, however even when used at ‘guesstimate’ settings it proved to be very quick in La Rochelle. Now having spent some time training with Josh and Andrew Murdoch back in New Zealand I have learnt much more about how to set it up correctly and it is proving to be very fast.

The sails I use are the MB1 (light air) and MB2 (medium/heavy air). I really like the MB2 but my MB1 had a bit too much luff curve in it to be really good below about 6 knots. I have just ordered a new RI-0 (the 2014 modified MB1) and Paul is taking some luff round out of that so we shall see how that improves things. Having sailed Josh’s and Andrew’s boats with Wilke masts (we all use Devoti hulls and north MB1/2 sails) I am more than happy with my Concept mast. Luca promised he would build me a fast mast and he delivered on that. As with my boat, when I ordered the mast from Luca I just told him my weight and left all the bend numbers to him….after all he has forgotten more about Finn masts than I will probably ever know.

Given enough time and money I am very sure the C-Tech mast could be developed to be a very quick light air rig. Unfortunately right now I don’t have those resources.

I haven’t used WB sails but the talk is they are fast light air sails and given their performances at the recent Worlds that’s hard to argue with. Doyle’s are also making some great sails through Rafa using their Stratis cloth. In the future I look forward to trying these sails out. However at the moment I am happy where I am as my boat speed is competitive across the wind range.

I can’t comment on Hit masts either, as to date I haven’t used one. However having talked to Jan I know they are constantly putting a lot of work into developing them and are using high tech carbon materials in their manufacture. Certainly many sailors have achieved great results with them.

Rig set up
The numbers that I follow are specific to my Concept mast which I know will be quite different from a Wilke or Hit mast. The basic concepts though I believe apply to all.

Light air (0-12 knots)
Leech tension = 28 kg (with Wilke masts it’s about 29-30 kg), this tension allows me to sheet close to the deck and onto the deck once the wind increases above 6 knots without having the sail leech too hard. Some vang sheeting is used in winds below 6 knots to bend the mast and shift the draft aft in the sail. As the wind increases above 10 knots a 2 kg chock is placed behind the mast so the leech can be tightened more for height upwind. In winds below say 6 knots the outhaul is pulled out hard and inhaul left right off. This again shifts the draft aft in the lower part of the sail and gives you height upwind. From 8-12 knots the inhaul can be pulled on a little and the outhaul eased for more power. Similarly the traveller position is brought inboard from the boom end sitting on the sheerline (hull/deck intersection edge) to the boom end being approximately 50-80 mm inboard from there. The centreboard is shifted as far aft as it can go to balance the helm, with just a bit of weather helm remaining for height upwind. The distance from the mast deck slot aft edge to the mast bearing ring aft edge is about 20-25 mm.

Medium air (12-20 knots)
From 12-15 knots leech tension is progressively tightened to 33.5 kg and the mast shifted forward in the boat so the distance from mast deck slot aft edge to mast bearing ring aft edge is about 50 mm. The centreboard is correspondingly moved from the aft most position to its forward most position. Inhaul and outhaul are tightened/loosened as required to depower/power up the sail. Traveller position is also altered from the boom end being slightly inboard of the sheerline (12 knots of wind speed) to about 50-80 mm past the sheerline (15 knots of wind speed). How much leech tension you use is a balance between height upwind, and being over powered through excessive tension. Cunningham is progressively pulled on to depower the rig as required...be careful though to not pull so much on that the sail runs out of luff round and starts to invert....that is slow.

From 15-20 knots I keep the mast base where it is and further increase the leech tension to 35 kg. This flattens the sail without unduly increasing the leech tension. At this tension the top of the leech opens sufficiently for my weight/hiking power to depower the rig as you hit waves and wind gusts.

Heavy air (Above 20 knots)
Well now to be honest I’m into unknown territory a little as I haven’t had a chance to train against Doc and Josh much in these conditions. However I would imagine the leech tension will then be progressively decreased through removing chocks at deck level to about 32 kg and the traveller released further outboard. The centreboard would simultaneously be shifted to the aft most setting. Cunningham, inhaul and outhaul would all be hard on.

All my chocks have written on them how much each one increases or decreases the leech tension.

My leech tensions have been arrived at through some quite extensive line ups with Josh and Doc as well as through outside observations of the sail by our coach John Cutler (1988 Finn Olympic bronze medallist) and myself. (Yes we have managed to tempt John into sailing the boat on the light days at least. Hopefully he will enter the Master fleet one day soon. I’m working on it.) This is something anyone can do if you can get a few mates together with a coach boat in attendance. It’s well worthwhile. One boat changes his settings at a time while the others remain the same until you eventually get to the fast setting. Then it’s the turn of your mates. It’s essential you share the knowledge you have gained with them so they can quickly improve too.

Physical fitness and strength
In these boats physical fitness is everything. You don’t necessarily have to be all that strong but you do need to be fit. Too often I hear I’m too old, I just can’t expect to compete with the young guys. Rubbish! As long as your body is still working, i.e. joints in good order, there is absolutely no reason, if you really want to, that you can’t be as fit as them. Our biggest problem is finding and making the time to get fit. We have jobs whereas their job is sailing. The biggest body issue I have recently found is that after a few hours hard training my knee joints were beginning to hurt. That has now been solved through taking collagen pills and deer velvet pills – apparently these help regenerate cartilage. I don’t know if it does or not but I do know they have got rid of my joint pain.

If you can bench say 95 kg and bicep curl 18 kg on each arm then you are strong enough. I think also with free pumping now being a normal sailing technique that having a strong core (abdominal muscles) is of the utmost importance if you don’t want to ruin your back later in life.

Free pumping
Some people get too carried away with this and just pump all the time without looking at why they are doing it. My advice is to start out slowly and only do it to catch the waves you otherwise would not have caught. Pick your moments and be wise about it. Then when you are on a wave look to see how you can immediately link that to another...and then another. With free pumping the rocking is just as important as the pumping and you need good balance as much as fitness and strength. I’m one for one off the boom up to about 18 knots then I go two to one.

To start the pump stand up (straight, not hunched), move right forward to the traveller and slightly to leeward so you lean the boat to leeward and the boom end almost hits the water. Then pull the boom back as you also lean back to sitting on the deck. This incorporates a rock and a pump for added acceleration. The big thing then (and this is where the fitness comes in) is to immediately and quickly stand and move right forward in the boat (keeps your weight forward so the boat accelerates down the wave) so you are ready to do it all over again as required to catch the next wave. As you catch and sail down the wave you have two choices – sail across the wave by the lee or on a broad type reach. Which way you go depends on where you see your next best chance for staying on the wave and catching the next. It’s fun! I think the best advice I can give is just go out by yourself and use the technique to catch waves and have fun. Before too long it will become more instinctive. There is no reason at 2:1 why you shouldn’t be standing up and be pumping and rocking in winds up to 25-30 knots. Balance is key then, but trust me it is significantly faster when you get it right.

Why the Finn is great
To me it looks fantastic, it glides through the water nicely, and the feeling of power from the rig is awesome. It is the most physically unrelenting boat I have ever sailed and ever will. The people who sail it are a tough breed and know how to handle pain. They are also highly intelligent, inquisitive and know what makes the boat go fast...and are constantly seeking ways to make it go faster. Anyone who has sailed a Finn for a good length of time has my respect.

The people in the class from the top to the bottom are also friendly and happy to share their knowledge. People I have recently met overseas who have provided invaluable help and stand out for me are Martin, Jan, Luca, Ed Wright, Rafa and Filippo Baldasaari. Guys like that make a class such as the Finn great. All the NZ Finn sailors are awesome people as well. Here, Ray Hall, in particular has gone out of his way to help me get started.

I have always wanted and dreamed of sailing a Finn. Every time I go out I think how fortunate I am to have realised this dream.

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