Subject: [harryproa] Re: leepods - con
From: "proaconstrictor" <>
Date: 2/13/2006, 4:24 PM

> > A)  Racing
>   If you're going to be racing or just horsing around, there's are
> of good arguments for the leepod.  It will let you fly the windward
> with more safety and less stress.  Since you're going to be on the
> sheets at all times, you should be able to dump the wind when the
> warns you that it's time to back off.
>   Some would say that the additional weight won't be worth it over
> entire length of a course, since flying a hull is mainly realistic
on a
> reach.  You could also argue that there's little reason to fly the
> because it will only save you 10% to 20% in drag, and strategy and
> handling will be more important than the drag savings.
>   I'm not going to argue for or against these points.  I'll just
> go along with the idea that a leepod could be a good asset when
> for max speed on an extended reach.

Are we talking pacific proas with pods or Harry's?

I don't personally see any reason to race either.  I know Rob wants
to and I am looking forward to it.  I just don't see the point at his

> B) Cruising
>   On the other hand, if you're going to be making a passage, then
> really is time to think of extreme situations.  How extreme? 
That's a
> matter of what you can afford to do given weight and cost
>   Of course, I'm an engineer, and tend to first think of designing
> extremes before designing for average conditions.  That's why I
wear a
> seatbelt, even though my car has airbags.  The airbags will be fine
> most conditions, but in the conditions they don't work, I'm not
> to pay the price for skipping the belt.

You can add airbags an a safety belt ot my proa any time you want. 
Messing around with major external features is a whole other
ballgame.  Your ideas aren't new ideas, they are the same old same
old everyone who starts reading throught the back files comes up
with.  I don't mean that as a knock mast bouyancy works, the Gougeons
use it on the G32 and it really works.  That is the only example I
know of where it actually self-rights, and you need rigging. 
Multihulls and certainly proa are a lively bet against the
conditions.  This is an extreme style of craft where a big bet that
sacrifices major features of normall craft has been undertaken, at a
severe functional penalty, in order to gain other advantages.  If a
person is uncomfortable with that bet the proven refuge is to mive th
bouyance, spar and, CG back to their normal positions.  Other ideas
are certianly worht considering.

>   As long as we're going to debate capsizing and self-recovery, we
> as well deal with the event of a complete knockdown, whether due to
> tall, steep waves, an unexpected gust, poor seamanship, or all
> After all, if you actually do go over in the middle of nowhere,
> little solace to be taken from the idea that the capsize wasn't
> likely.

A knockdown and a capsize are two different things.  Which are you
talking about?

Regardless of whether or not other boats would have failed.
>   A Harry or Visionarry, with a sealed mast, will be just about the
> cruising multihull you'll be able to recover from a full
> This is because there's nothing leeward of the mast, and it
> enough flotation to stay at 90 degrees, or even a bit past. 

This is exactly the situation where the PP with a pod pops right back
up.  In reality it doesn't go over to 90 because the wind force
relents at that point if yuo get your sails under or on the water you
are in serious trouble. with anything other than a beach boat.

Once the
> windward hull weathercocks downwind, wind and wave action alone may
> enough for self righting.  If not, you could use a kite or a sea
> to pull the windward hull back down.  No complex righting or
> maneuvers required.

I am not convinced.  If you are talking wind only then the PP with
pod is way ahead of you as far as recovery is concerned.  If you are
talking about wave conditions that did this or an oughtright savage
attack of both, you are in serious trouble and waiting around and not
coming back.  You needed to be have set out your drage device long
before this happened.

>   That's pretty significant if there's no one around to help you
> the boat.

Pipe dream

>   A schooner rig will be even more stable, and the additional
> flotation would increase the margin of safety.  Some argue for
> gas-assisted flotation, others fixed.  Regardless of the flotation
> the question is:  can we afford this margin of safety given its
> on performance, cost, and weight?  Given that any  flotation system
> going to add less than $10,000 to the price of the boat, and the
> will be negligible, the answer is yes.
>   My worry about the leepod is that the higher the leeward hull
> in a capsize, the more past 90 degrees the windward hull will heel,
> the more heeling moment it will create. 

Doesn't work that way, but I wouldn't put one on a harry generally
either, for one thing the leeward hull is too low, and the windward
hull is probably coming over no mater what you do.

> to leeward of the masts can potentially add more heeling moment if
> boat goes past 90.

The weight of hulls is far less than the bouyant force.

>   Once the extreme is reached, I'm a bit leary of anything that
> make recovery harder rather than easier.

No large multihull has ever recovered from capsize/knock down, as far
as I know?  Another factor is that selling these schemes has wrecked
the market for multihulls over the years, which is irrelevant, of
course, except if you want to get these ideas used.  10K is a lot of
money and I would sopend it on stuff that would get the boat in
position to survuive the first wave not on dreams of recovery.  Just
me though. 

If you could get a more stable craft to also recover that would be a
great thing.  Here is the problem:  From a design perspective
stability of multihulls rages from tippy like a barrel on the water,
to stable like a block on the water.  Boats that are tippy can be
designed for ease of recovery, boats that are stable are not easy to
recover.  Creating a Transformer, a boat that one moment is tippy,
but the next is stable is technically very difficult, and has never
been done as far as I know.  The G32 and Russ' boats are all tippy to
start with.

> ---

Yahoo! Groups Links