Steinlager 1 Trimaran

hi there
I have photo's on external hardrive of Blake and a boatbuilder working on the wing with the web exposed I will fish it out and post when I get near the hardrive as its in Nelson base and I'm in Christchurch base for a few more weeks. Its an awesome shot.

 

Wow that would be interesting... any photos you have would be great ... im not after nice shots... im after all angles of the boat.

Cheers very much

 

...mmmmm, TAD, maybe you can explain a few things please...firstly, the centreboard rakes fwd.....secondly, why do so many cats have such massive rake in their masts, I understand Cof E and CLR, but find it strange that the cats rake so much (compared to monos), there must be a logical reason.....any ideas please

 

Usually a dagger or foil faces forward to cut ventilation (only when flying the main hull in this case) when the board/foil could suck air down the leading edge, raked forward this is reduced considerably or even halted, and in the big tri's case, board aeration could allow the boat to step sideways while hard beating, (but probably unlikely with a buried leeward float). But lifting the board shifts the CLR aft while area is reduced, for better helm balance in hard conditions. On conventionally raked aft boards, weather helm increases with board lifting, the opposite of what you want. Actually Steinlager 1's mast was not raked very much. Hobies rake theirs to shift the CoE aft to load up their rudders for better windward performance, because they have no dagger or centreboards. Also raked rigs look traditionally and fashionably cool, be it on sharp, historical, clipper ships, pilot boats or modern multihulls. Just imo of course.

 

Some boats rake the mast so the step is on a beam but the CE is back where needed. In the old days on a raked rig the halyard could lift cargo out of the hold on merchant craft.

 

In addition to what Gary said.....the forward raked board will (hopefully) slide up in it's case when you hit something, rather than busting the case or board.......

Mast rake seems to be mostly a styling statement unless it's done to fix a problem.....but I'm not really a multihull designer so there could be a reason that eludes me......Generally the radical rake looks fast....

 

Hi Gary,

Regards forward raked boards;

Do monohull keels work the other way around? I'm sure Brett Bakewll-White indicated to me at some stage that forward raked keels were not ideal on monohulls due them ventilating and stalling. My enquiry to Brett was regarding the One Metre Class r/c yachts. Back in the early 90's several designs including John Spencer (original promotor of the class in NZ) used forward raked keels, but they fell from favour and vertical variety has become the norm.

Apologies for getting off topic.

Tony

 

The main advantage of forward raked foils, that I'm familiar with, is as Gary said when the foil is airborne because it reduces the chance of ventilation.
Extensive experimentation was done in the Moth class to determine the right angle which is about 7 degrees:

 

The earliest raked forward keel was probably Alan Swarbrick's Whitread 60 Tokio and apparently the boat worked very well, although a Farr designed Tokio was chosen for the race, think that is correct. Brett Bakewell-White's 6.5 Mini-Transat had a raked forward, canting keel for Chris Sayers. I don't believe Brett would gave said the acutely angled keel would have ventilated; maybe with crazed driver Sayers cranking the keel and bulb to the surface, it might have done so.
Also guessing, monohull keels whether fixed or raked, would be ******** for picking up weed - whereas on a multihull you can lift them to clear. Also there has to be big loads, also more twisting with the bulb weight well forward, placed on the blade/hull connection areas. And it would be easier to build/fit vertical keels, so that maybe the reasons they have lost favour.
Profile of Bakewell-White Wildcard

 

...emmm, thanks fellas, interesting

 

As mentioned the shot of mast gives an idea of scale....JFWIW