In a message dated 4/11/2005 8:15:37 A.M. Eastern Daylight Time,
georgs@trawlering.com writes:

Anyone on Power Catamaran List have any comment?      --Georgs

Hi Georgs and list,

I've been having a dialog with Bob  Austin on this subject off-line, thought
I'd post some  highlights here.  (I have heavily edited Bob's letter.)  Henry

In a message dated 4/9/2005 6:04:35 P.M. Eastern Daylight Time,
thataway4@cox.net writes:  (sections snipped)

Henry, I am finally back home and have a few minutes to  answer some of your
comments...

My personal interest in cats is the  shoal draft and fuel efficiency--my home
dock has a limit of draft of 3  feet because of a sand bar...

As far as safety -- The cats have  very high initial stability--it takes a
large force to get them to heel more  than 10 degrees.  However the ultimate
stability is 90 degrees or  less.  Thus if a cat is heeled at 80 degrees in a
storm there is a very  good chance it will not recover--and will assume its most
stable  position--upside down.  (this is why most ocean going cats have an
escape  hatch in the bottom of the center pod).  Definitely a monohull of 34 feet
is safer than a PDQ--the PDQ is light and has very quick motion.  I think
that if you were to pin the folks at PDQ down--that they would agree that it is
not a passage making boat.  I have rolled a boat to 90 degrees in hurricane
force winds on a North Atlantic crossing--my boat was an extremely seaworthy
motorsailer--and I suspect that most power passagemakers in that size (62
feet  length over all) would have also had serious problems in these types of
seas.  <snipped>

Hope that some of this is of  value.  Please understand I am being the
devil's advocate--and am still  interested in cats--but I think that there quite
some way to go--at least in  the production boats.

Best Regards,    Bob  Austin

In a message dated 4/11/2005 3:08:01 P.M. Eastern Daylight Time, HClews
writes:

Hi Bob,

Thanks for your thoughts and insights.  I  wasn't even aware of the "POP"
list, I'm glad you mentioned it, I've just been  browsing the archives. (Just
today, I see a post transferred from there by  Georgs to the PCW list).

I'm not sure I agree with you that a "34' monohull  is safer than a PDQ", it
seems to me there are many variables.  I agree the  cat will likely end up
inverted if it gets rolled close to 90°, but  I'd think the chances of it
reaching that angle might  be somewhat less than the monohull in the same conditions
-- what say you?  As you probably know, PDQ has done a  complete stability
analysis, some of which appears on their website (click  on "Technical" under 34
Powercat).  When I go up there for a factory visit  at the end of this month,
I plan to ask them more about this, particularly  how one might escape from
an inverted Powercat 34? I do know that they are  planning to incorporate an
escape hatch in their new 40' powercat.  (I  wonder how many powercats actually
do this now?)

Anyway, every boat is a compromise, as they  say.  Clearly, I would not
choose a PDQ-34 for a trans-Atlantic  crossing. (I've got to agree with a PDQ owner
who said recently -- on  PDQforum.com -- that "anyone who wants to take an
MV-34 across an ocean  should talk to the nice folks at Dockwise").  But for
coastal  cruising and southern islands, it seems OK to me.  (I'm waiting to  hear
more details from a couple who is just returning from a winter cruise as  far
south as Roatan in their PDQ 34.  I gather they've had some  "adventures" but
are still doing just fine).

To me, the basic appeal of the catamaran is it's  ability to beat the
hull-speed limitation of a displacement trawler  while avoiding the excessive fuel
cost and range limitation  of a planing monohull.  I see it more as an
alternative to a planing  (or semi-displacement) monohull than to a displacement
trawler.  For  us, the great majority of use will be coastal, even inland,
cruising.  We want a boat that's FUN and user-friendly.  Being able to cruise at
15-kts (without burning 20+gph) adds to the fun.  Having a (protected) draft of
under 3' also adds to the  fun.

I don't think any small boat is much fun in rough  seas, and there's little
doubt that a lightweight cat will be  worse (less comfortable) than a monohull.
But this is only one of  many considerations.  In the much more
frequently-occurring light-to-moderate chop, the catamaran shines.  The smooth ride of a
powercat headed into 2-4' seas is quite  remarkable.  Many other features
make the powercat a desirable coastal  cruiser: shallow draft, beachability, easy
access from water or dock (built-in  steps), large interior space for the LOA
(cheaper transient dockage rates),  and of course, good fuel economy at
higher speeds.

I agree that the much-touted efficiency  of the cat has its limits.  It's
pretty clear to me that cats have  no real advantage at displacement speeds --
the extra wetted surface  adds additional drag.  Also, especially for narrow
beam cats, there is wake  interference between the hulls.  So, the big advantage
is really  for folks who want more speed.  As long as the load is kept
reasonably  light, a well designed powercat can cruise at 15-16 knots while using
less than half the fuel of a equivalent sized monohull.  To me  this is very
appealing, particularly as fuel prices climb above $2/gal.  And, even though the
cat is not any better than a monohull at low speed, it can  be made to be
almost as economical -- simply by slowing  down.  I'm hoping to document this
further, but it's my understanding that  the PDQ 34 burns just under 5-gph at
15-kts, but less than 2-gph  when slowed down to 7-kts.  If true, this means that
range on the  (admittedly limited) available fuel (185 gallons) could be
extended to a  bit over 500 nautical miles.  That's enough for any passage I'm
contemplating.  In this month's Passagemaker, there's a chart  showing fuel
stops south of the border, the longest run shown between San Diego  and Key West
(through the Panama Canal) is 436  NM.

Thanks again, I appreciate your  comments.  But I sometimes wonder if you're
not being a bit  too theoretical about all this.  At some point, you have to
chose  what's best for you based on the best info at hand.  One thing I like
about  the PDQ is that they've built a bunch of boats, and they're constantly
improving them with owner feedback.  IMHO, it is next to  impossible to build a
one-off boat (especially something as tricky as a  catamaran) that will prove
satisfactory in all conditions.  (But,  if I were going to do this, I'd
certainly want Malcolm Tennant as  my designer!)

Cheers,
Henry

Henry,

Can you please explain what you mean by  a "Passage making boat" and what
you  mean or imply by  use of  the term "Offshore Service".

Any thoughts about the recent world record using catamaran hull beating
hurricane/typhoons and other weathers?

Got a couple more Q's too.

Thanks,

Pierre

-----Original Message-----
From: power-catamaran-bounces@lists.samurai.com
[mailto:power-catamaran-bounces@lists.samurai.com]On Behalf Of
HClews@aol.com
Sent: Monday, April 11, 2005 3:45 PM
To: power-catamaran@lists.samurai.com
Subject: [PCW] Suitability for offshore service

In a message dated 4/11/2005 8:15:37 A.M. Eastern Daylight Time,
georgs@trawlering.com writes:

Anyone on Power Catamaran List have any comment?      --Georgs

Hi Georgs and list,

I've been having a dialog with Bob Austin on this subject off-line,
thought I'd post some highlights here.  (I have heavily edited Bob's
letter.)  Henry

In a message dated 4/9/2005 6:04:35 P.M. Eastern Daylight Time,
thataway4@cox.net writes:  (sections snipped)

Henry, I am finally back home and have a few minutes to answer some of
your comments...

My personal interest in cats is the shoal draft and fuel efficiency--my
home dock has a limit of draft of 3 feet because of a sand bar...

As far as safety -- The cats have very high initial stability--it takes a
large force to get them to heel more than 10 degrees.  However the ultimate
stability is 90 degrees or less.  Thus if a cat is heeled at 80 degrees in a
storm there is a very good chance it will not recover--and will assume its
most stable position--upside down.  (this is why most ocean going cats have
an escape hatch in the bottom of the center pod).  Definitely a monohull of
34 feet is safer than a PDQ--the PDQ is light and has very quick motion.  I
think that if you were to pin the folks at PDQ down--that they would agree
that it is not a passage making boat.  I have rolled a boat to 90 degrees in
hurricane force winds on a North Atlantic crossing--my boat was an extremely
seaworthy motorsailer--and I suspect that most power passagemakers in that
size (62 feet length over all) would have also had serious problems in these
types of seas. <snipped>
Hope that some of this is of value.  Please understand I am being the
devil's advocate--and am still interested in cats--but I think that there
quite some way to go--at least in the production boats.

Best Regards,   Bob Austin

In a message dated 4/11/2005 3:08:01 P.M. Eastern Daylight Time, HClews
writes:

Hi Bob,

Thanks for your thoughts and insights.  I wasn't even aware of the "POP"
list, I'm glad you mentioned it, I've just been browsing the archives. (Just
today, I see a post transferred from there by Georgs to the PCW list).

I'm not sure I agree with you that a "34' monohull is safer than a PDQ",
it seems to me there are many variables.  I agree the cat will likely end up
inverted if it gets rolled close to 90°, but I'd think the chances of it
reaching that angle might be somewhat less than the monohull in the same
conditions -- what say you?  As you probably know, PDQ has done a complete
stability analysis, some of which appears on their website (click on
"Technical" under 34 Powercat).  When I go up there for a factory visit at
the end of this month, I plan to ask them more about this, particularly how
one might escape from an inverted Powercat 34? I do know that they are
planning to incorporate an escape hatch in their new 40' powercat.  (I
wonder how many powercats actually do this now?)

Anyway, every boat is a compromise, as they say.  Clearly, I would not
choose a PDQ-34 for a trans-Atlantic crossing. (I've got to agree with a PDQ
owner who said recently -- on PDQforum.com -- that "anyone who wants to take
an MV-34 across an ocean should talk to the nice folks at Dockwise").  But
for coastal cruising and southern islands, it seems OK to me.  (I'm waiting
to hear more details from a couple who is just returning from a winter
cruise as far south as Roatan in their PDQ 34.  I gather they've had some
"adventures" but are still doing just fine).

To me, the basic appeal of the catamaran is it's ability to beat the
hull-speed limitation of a displacement trawler while avoiding the excessive
fuel cost and range limitation of a planing monohull.  I see it more as an
alternative to a planing (or semi-displacement) monohull than to a
displacement trawler.  For us, the great majority of use will be coastal,
even inland, cruising.  We want a boat that's FUN and user-friendly.  Being
able to cruise at 15-kts (without burning 20+gph) adds to the fun.  Having a
(protected) draft of under 3' also adds to the fun.

I don't think any small boat is much fun in rough seas, and there's little
doubt that a lightweight cat will be worse (less comfortable) than a
monohull.  But this is only one of many considerations.  In the much more
frequently-occurring light-to-moderate chop, the catamaran shines.  The
smooth ride of a powercat headed into 2-4' seas is quite remarkable.  Many
other features make the powercat a desirable coastal cruiser: shallow draft,
beachability, easy access from water or dock (built-in steps), large
interior space for the LOA (cheaper transient dockage rates), and of course,
good fuel economy at higher speeds.

I agree that the much-touted efficiency of the cat has its limits.  It's
pretty clear to me that cats have no real advantage at displacement
speeds -- the extra wetted surface adds additional drag.  Also, especially
for narrow beam cats, there is wake interference between the hulls.  So, the
big advantage is really for folks who want more speed.  As long as the load
is kept reasonably light, a well designed powercat can cruise at 15-16 knots
while using less than half the fuel of a equivalent sized monohull.  To me
this is very appealing, particularly as fuel prices climb above $2/gal.
And, even though the cat is not any better than a monohull at low speed, it
can be made to be almost as economical -- simply by slowing down.  I'm
hoping to document this further, but it's my understanding that the PDQ 34
burns just under 5-gph at 15-kts, but less than 2-gph when slowed down to
7-kts.  If true, this means that range on the (admittedly limited) available
fuel (185 gallons) could be extended to a bit over 500 nautical miles.
That's enough for any passage I'm contemplating.  In this month's
Passagemaker, there's a chart showing fuel stops south of the border, the
longest run shown between San Diego and Key West (through the Panama Canal)
is 436 NM.

Thanks again, I appreciate your comments.  But I sometimes wonder if
you're not being a bit too theoretical about all this.  At some point, you
have to chose what's best for you based on the best info at hand.  One thing
I like about the PDQ is that they've built a bunch of boats, and they're
constantly improving them with owner feedback.  IMHO, it is next to
impossible to build a one-off boat (especially something as tricky as a
catamaran) that will prove satisfactory in all conditions.  (But, if I were
going to do this, I'd certainly want Malcolm Tennant as my designer!)

Cheers,
Henry