Stiff Finns

Originally posted by bigwavedave I've had older Finns and modern Devoti Finns. I had carbon wing masts and sails that matched the bend of the mast on all of them. Of the older Finns my Vanguard had a much softer bow that the Taylor. It was noticably faster on both flat water and waves. The Devoti also had a soft bow, but the rest of the boat was stiff, apart from the fordeck which had a bit of flex in it. More so that the Vanguard. It was so much faster than the Vanguard. The Vanguard was down to weight (still had correctors in it) and had a very good swing test. Obviously the Devoti was a newer boat but the difference was remarkable. Quite why I don't know, but a fast Finn needs a bit of flex in the bow area. Those stiff Finns that Rodney talked about were horribly slow.

How does a new Marder hull rate? A friend of mine sold his older Marder
and got a brand new one for a ridiculously high price and is now very
pis**d off that he did, since the mate he sold it to is doing much better in
the older one.

so is it in fact an acceptance that perhaps the hull isn't as outright fast on flat water in return for a bit of forgiveness in big seas? As an analogy, F1 suspension versus rally suspension?

I know very little about Finns, but at a guess, as soon as you are talking about an unstayed rig, then surely hull stiffness becomes quite academic?  At a guess, stiff hulls are not about the boat not "deforming" as it hits waves (as the boat is up and down and all over the place anyway), surely it's all about the rig staying exactly how you want it, no forestay sag, and that power going straight into the boat?  Take away the standing rigging and replace it with a "soft" rig like a Finns, and I could see that a bit of give would be a very good thing.   And the Finn is not exactly a seakindly shape...it's very blunt by modern standards!

I've sailed my missus' Europe quite a lot, especially in a blow, and it's just like a little Finn.  I'm still trying to get my head round the whole "everything works in reverse" rig settings etc, but I do wonder how much stiffness is added to the hull when the main in cranked in hard with the boom on the deck going upwind.  I'm amusingly too big for it but it's a good laugh in a blow, and I imaging it's a very technical boat and very hard to sail well (slight threadjack, sorry)

The reason is possibly this, but I´m just an amateur. Best bet is to consult
Frank Bethwaite and others.

Having a "stiff" mast as in the Finn, which is set more or less within a
frame dependent upon crew weight for you to choose, by the class rules(?
Lukiepie Walker) and possibly an advantage for the boat under other
conditions, all other things being equal, makes the rig with a stiff hull
rock over the waves, and consequently slow down. If the energy of wave
impact is transfered to either a flexible mast or a softer, more giving hull,
the result is the mast or hull gives, enabling a smooth run over the wave
without braking and the energy is then dissipated to the wave out the
back of the boat as it clears the wave and goes into the next trough
(more or less). That´s why the Devoti Finn hull IMHO has its flex
characteristics.

Personally, I'd sooner have a flexible ("automatic") mast and stiff hull than
a stiff mast and flexible hull though, one of the reasons being that you
can tune the rig characteristics to suit the average conditions at the time,
but you can´t tune the hull of a boat. Don´t know whether this is just
bull, but there's my ha'penny's worth.



Edited by Slippery Jim

I realise that no one here is likely to believe the wisdom from the Finn sailors, builders and gurus, even after more than 60 years of development.

So, heres an extract from Y&Y's own Jeremy Evans test of a Finn (FYI carbon can only be used for local re-inforcement for reasons of costs in the Finn class so I am not sure about the Pusan Olympics boats but I know that they are very stiff).

Advantages in modern construction don’t

necessarily include the fanciest materials. Hyundai

built an all-carbon fleet for the Pusan Olympics

which proved uncompetitive elsewhere. A totally

rigid carbon Finn does not flex and will

consequently pound and go slowly through waves.

By comparison the Devoti Finn is moulded in

fibreglass laminates using vinylester resin, with a

deck and bow area that are very flexible — you can

feel things moving, which is quite weird on such

an apparently solid, heavyweight boat. The

construction of the Devoti Finn has been designed

to absorb maximum wave impact, allowing this

unusual dinghy to power ahead with the ‘nothing

can stop me’ feel of a racing keelboat.

Edited by rodney