I agree, with the points regarding the benefits of the leepod.
As for recovery in case of a capsize, I tend to favour the ama
flooding idea. Having heavy equipment like engine and anchor tackle
to ww would probabely sink a completely flooded ama. Need to choose
non very buoyant building technique. Denser material would fit better.
Once having sunk the ama, the crew would be able to retrieve a
halyard or running backstay to lever the ama up again, on the other
side. Using the mast as lever. Using fenders and other buoyant stuff
as fixed point. Maybe a dedicated rightening buoy. A reasonable
reduction on the running backstay. In this case the leepod would even
be beneficial givin a better, outward angle to the masttop.
All this calls for:
- a non too buoyantly built ama without reserve/emergeny buoyancy.
Unless its removable in case of capsize... good idea. It might be the
later used rightening buoy. Inflated, flexible water containers.
- a non too buoyant aka construction.
- an effective way to flood the ama.
- only little buoyancy of the cabin to of the hulls gunwahle, so to
ww. Assuming that the cabin would be on the vaka, not ama. ´Cause if
it were to ww and on ama, why would you want a leepod anyway?
- Enough weight to sink the ama,
- some reserve buoyancy in the vaka, to keep it floating even flooded,
- A good bailing bucket. to get the boat dry again.
- A reasonabely fit crew and moderate weather.
Might seem like a long list to most. But it does not sound impossible
to me. On the contrary.
Peter
--- In harryproa@yahoogroups.com.au, Mike Crawford <jmichael@g...>
wrote:
>
> >
> > "In breaking seas, if hit from the side by a breaking wave it
could
> > dig in and flip the boat."
> >
> > Not heard of that happening, doesn't seem to be a serious
objection.
>
>
> This is probably more of a problem in theory than in practice,
but
> hey, that's why we're all here batting the ideas about.
>
> Leeward-pod proas have been through some pretty heavy weather, so
we
> know they can be seaworthy in good hands. I still like to keep
> challenging the design, though, to eliminate as many potential
problems
> as possible.
>
>
> > "It also makes the boat less likely to be stabilised by mast
bouyancy
> > from going over further."
> >
> > Right, stabilizing with mast bouyancy is not what one wants in
the
> > kind of situation that causes a capsize in the first place.
> > Self-righting is the proven concept
>
> Could you explain this in more detail? I think that self-
righting is
> a wonderful thing, but don't yet see how a leeward-pod proa would
right
> itself in a knockdown or wave-induced capsize.
>
> Rob's explanation of a harryproa recovery makes sense: the boat
floats
> at 90 degrees supported by mast buoyancy, the windward hull
weathercocks
> to leeward, and then a kite or weight is used to pull the windward
hull
> back down. I wouldn't want to try it on a bad day, but at least
it's
> possible. Something like that would never, ever happen on most
cruising
> cats.
>
> I can see how the leeward-pod proa will work well for a wind-
induced
> capsize, especially if the knockdown isn't complete. Forgetting
the
> rig, that pod will keep the boat from going over in many or most
cases,
> so there's no need to worry about mast buoyancy.
>
> But what about a more extreme condition, such as a massive gust,
a
> large steep wave, or a combination of the two? If something were
to
> push a leeward-pod proa past 90 degrees, how could it be righted
again?
> I would think that anything that extends past the hull would make
it
> more difficult to flip the boat back upright..
>
> It seems to me that a) the harryproa will normally have a greater
> righting moment when sailing, b) while the leeward-pod proa will
be
> more resistant to capsize if you push the boat past 30 degrees, but
c)
> the harryproa will have a much greater chance of getting back on
its
> feet if pushed to 90 degrees.
>
> It's a series of tradeoffs I like the harryproa approach, but
I'm
> clearly biased. However, if I can learn how a leeward-pod proa
will
> self-right, that could certainly change things.
>
> - Mike
>
>
>
> proaconstrictor wrote:
>
> > "My objection wasn't with the Pacific proa. I have great fondness
for
> > it after my time in PNG. I believe it has its place but not for
long
> > haul cruising."
> >
> > That is a fair point, but it falls into the same category as a
cruise
> > ship passenger wondering why someone would cruise on any sailing
> > multihull. Russ Brown doesn't recomend that you or I do it, you
have
> > to want to do it for whatever wacky reason.
> >
> >
> > "My objection is the use of the lee pod as I believe
> > that it is an unseaworthy attachment. I can almost see some value
in
> > it for flat seas as training wheels and as a lee platform for
> > drifting conditions but not once there is any swell. I can't see
how
> > it can help prevent combination wind/wave capsize."
> >
> > Right answer, wrong question. It's not aobut capsize, but self-
> > righting, and it doesn't prevent knock down it just rights from
it.
> >
> > "On the side of a wave the boat would have to be about 90 degrees
> > before the leepod contributed to righting moment."
> >
> > Right at the point where a PP without one might become stable in
the
> > knock down position, it is doing it's work. Somewhat similar to
what
> > ballast does in the same situatiom.
> >
> > "In breaking seas, if hit from the
> > side by a breaking wave it could dig in and flip the boat."
> >
> > Not heard of that happening, doesn't seem to be a serious
objection.
> > Reminds me of the Wharram/Boon drawing of a tri perched ona
rbeaking
> > wave about to get rolled over. It might happen, but it either
> > doesn't or they have the sea anchor out, one hopes the literature
is
> > not full of that kind of capsize.
> >
> > There isn't much evidence of the pods digging in either, depends
on
> > the exact shape, but generally they seem to rise out of a wave.
> >
> >
> > "It also
> > makes the boat less likely to be stabilised by mast bouyancy from
> > going over further."
> >
> > Right, stabilizing with mast bouyancy is not what one wants in the
> > kind of situation that causes a capsize in the first place. Self-
> > righting is the proven concept, or as with conventional cruising
> > multis a very high resistance to capsize. Low resistance to
capsize
> > combined with high stability in the capsized or KD position is
not a
> > winner.
> >
> >
> >
> >
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