torsdag 18 mars 2010

Alexander Simonis om segelval och påverkan på designen

Jag ställde några frågor till Alexandr Simonis ena halvan av konstruktörs teamet till våran Grynet. Kan ju vara kul så här i segelköpar tagen.

How do you consider different sail configurations when optimizing the design?

"This depends on what kind of yacht it is, Cruising/racing, round the cans or round the world.
Where the yacht sails, what time of the year and what general conditions it can experience all influence the sizing of the rig and sails. Quite often we look for weather data if it concerns a specific event or specific area where the boat is sailing or needs to perform at it best.. The extracted wind models are then set up in a VPP to run the yacht against. Then Different sail sets are considered, this then goes back the ratings if it involves a rating based design. If not it stays in the loop of optimizing hydrodynamics (hull/appendages) against aerodynamics (rig/sails)."

To build a fast 35 foot boat that fits both ORCi and IRC. What is your opinion about what we should look for? Rules of thumb?

"Weight is still King, I think if the boat is well build and as light as possible you have a basis
From which you can optimize towards either rule.(within reason that is). "

- Jib vs. Genoa?
"The general trend is to move away from large overlaps, under either rule."
- Should it be high Jib area/mainsail area factor?
"It is all about balancing, but you do have more control over a main than a jib in term of trimming it , that makes is more versatile and ultimately allow you to sail with a smaller sail wardrobe than back in the IOR day’s with the big over laps. (Light, ,medium, heavy no:1 and so one). Unfortunately the rating rules like IRC haven tended to put more and more weight on the main in terms of rating which may slow this down and push us towards going a bit bigger again on the headsails. I think we only will see subtle differences in time to come and maybe also venue/location driven."

- Gennacker vs symmetric spinnaker.
"The development in Asyms’ in progressing at a much more rapid rate than than the symmetric ones, if you look how much asym’s improved over the last 10 years, In combination with lighter faster boats it is the way forward."

- Weight – is there an ideal weight
"Many of the new boats feels like heavy boats. It’s rule driven, Up to now really without exception you see each and every rule as it is used over time, ending up with heavier and heavier boats to fit in well under the rating. It’s maybe not
that easy to address for the rule makers but it’s not nice. No matter what, heavier boats are more expensive and in general slower so who really want that."

I have a feeling that the bigger the jib is in relation to the main sail the easier is it to get a jib configured boat to move. Is it so or is it just a fix idea?

"I think it is just a feeling maybe based on what reaction an action gives, the headsails only being attached to the forestay, are really giving maybe better feedback to what is happening,
With the sheet loose the flap and do nothing, while sheeting in the flapping stops and drive
Is generated. The main on the other hand is much more restrained by the mast, boom, battens and headboard so it doesn’t move as much as the headsail does when moves the sheet. Also the main has a disturbed flow to start of with caused by the mast, the headsail, specially on a head foil has that far less. It is a function of balancing, and a total amount of sail area needed.
For a certain mastheigth/weight/cg you really like to get on as much (efficient) area as possible so you spread it out over the main and the jib."

Här är länkar till hela Alexander Simonis serien:

Kolla också:
Alex Simonis om köldesign:
Alex om Americas Cup, flerskrovsdesign och framtiden fö Cupen:
Alex om designverktygen och ORCi och IRC:

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