On Mon, Mar 17, 2008 at 9:03 PM, Mark Stephens <mark@harryproa.
For what it's worth, from my perspective, all three of you have been
reasonable up to this point, and I see no reason for additional
discussion in this forum.
Harryproas are amazing designs that do several things very well. But
they don't do everything well -- no boat does. As Rob pointed out back
in 2002, sailors are notoriously conservative people, and the
accommodation-
In the meantime, this makes for a difficult business. There
inevitably is friction between people even when business is going well
and the money is flowing in. When trying to get a business off the
ground selling such a radical design, things are much tougher. I'm
grateful that the three of you have stuck at it as long as you have.
I'm also appreciative that you've found an amicable way to let Rob
continue on with the Harryproa designs.
In the end, all three of you are right. Rob was right in that there
was tension, for which he blamed no one, and that the web site updates
sometimes took a while. It was reasonable of Michelle to not want to
see comments like that in the open forum (which was a mistake on Rob's
part, and for which he apologized). Mark is right in that an unstayed
proa is not better than a catamaran at everything. None of this is
particularly negative nor unfair.
In the end, the three of you have had a tough time in a challenging
situation, and have really come up with great designs, as well as a
good plan for moving forward.
Let's just leave it at that, and get back to talking about proas.
- Mike
Rob Denney wrote:
snip
>
> Rob has requested I not make any further 'negative' comments on
this
> group. I believe that a discussion group should be open and free to
> express an opinion without it being seen as disparaging; a
discussion
> group that only allows the views of the moderator is of little
value.
> As Harryproa is now Rob's I will honour his request and
> not make any further posts. I do reserve the right of reply to
Rob's
> last post and hope it is seen as a useful discussion.
G'day,
My request was in a personal email in totally different context to
that above. I don't discuss personal emails on public forums so that
is all I will be saying about it.
If Mark (or Fritz, or Todd or any of the other dissenters i have
welcomed to the group in the past) want to post, they are welcome.
The only posts that have ever been censored on this group (2943-2946)
were from me and were chopped without my permission a week before I
received ownership.
Replies to the rest when I cool off a little.
regards,
Rob
>
>
> >
> > G'day,
> >
> > On Wed, Mar 12, 2008 at 10:14 PM, Mark Stephens wrote:
> > > I've never been quite sure about the extra sailing loads
argument
> as the rigging loads on a cat are taken by strips of uni in the top
> and bottom of the bulkheads, not a big deal.
> >
> > There is about as much material in these strips as in the
glass which
> > goes around the hull to support the harryproa mast.
>
> I agree.
>
> Other
> > comparisons are:
> >
> > 1) The cat has a substantial transverse bulkhead to keep the
strips
> > apart and take the sheer loads, and a substantial compression
post
> > under the mast, all of which needs to be very solidly glassed
to the
> > very solid bridgedeck, hull and cabin roof. Some also have
fore and
> > aft bulkheads to prevent the main beam buckling.
> >
> > Harryproas have a single ring frame in the hull. Weighs less
than 10
> > kgs glassed in.
>
> True but a catamarans bulkheads don't just hold the rig up they
also
> hold the hulls together, segregate the boat into cabins, holds up
the
> bridgedeck etc etc. Either only include the extra uni reinforcing
in a
> cats bulkhead or add the weight of a proas beams to make weight
> comparison fair. The mast compression post isn't very heavy,
usually
> just a piece of western red cedar glassed to the bulkhead.
>
>
> >
> > 2) The fore and aft loads on the cat are enormous and require
the
> > hulls to be beefed up (either with extra material or bigger
> > dimensions), plus a forebeam, a seagull striker and a
mainsheet
> > traveller with a large beam to support it.
>
> No extra material is needed for fore/aft loads, the existing
> dimensions and laminates are enough to take care of these. True
about
> the forebeam and mainsheet track but these are no heavier than the
> heavy balestron boom. Not having so many mainsheet control winches
on
> a proa is a big plus.
>
>
> The forebeam then needs a
> > lot more hull height to keep it out of the waves. Not only
heavy and
> > added windage, but it is in the extreme bow of the boat
adding to the
> > pitching moment.
>
> Agree with this. Not having a fore beam and tramp is a great safety
> advantage and Harryproas certainly pitch a lot less than cats.
>
>
> >
> > Harryproas have a simple stringer along the deck and the keel
between
> > the beams. Maybe another 10 kgs.
>
> Modern cats don't have any stringers along the deck but do have
souls
> and webs to walk on. Proas require an extra layer of glass over the
> leeward hull between the beams to take the mast loads, about 50kg.
>
>
> >
> > 3) Cats, especially those with the user unfriendly 3 stay
rigs also
> > need considerable structure to support the chainplates.
Minimum is a
> > decent thickness half bulkhead, solidly glassed to the hull
and deck.
>
> Most catamarans use an existing bulkhead to attach chainplates with
> some extra reinforcing.
>
>
> >
> > Harryproas don't.
> >
> > 4) The cat needs beefing up of the cabin top to take the
headsail
> > track loads and the winches for the sheets.
>
> Not really much beefing up. A well designed saloontop with enough
> glass and thickness to support walking on will be enough to take
the
> jibsheet loads with maybe an extra layer around the jib sheet
track.
> Again, not having winches is a big proa benefit.
>
>
> >
> > Harryproas don't.
> >
> > > Also weight isn't necessarily a big factor. Where a proa
saves
> weight is in not having so much material as they don't have such an
> extensive fitout, and not so much solid bridgedeck and saloon. I
think
> a proa built with the same accommodation and appointment as a cat
will
> weigh about the same.
> >
> > Weight is a huge factor. Blind Date has 2 doubles and a
single berth
> > with space for 2 more single cabins , huge deck space, covered
> > cockpit, galley, large nav station and toilet. It weighs 2
and a bit
> > tonnes/tons in sailing trim. There are no catamarans with
similar
> > usable space that are anywhere near this weight. Lower weight
means
> > smaller motors, smaller rigs, higher speeds, lower build and
> > maintenance costs, less to paint, easier to haul out, etc etc.
>
> Blind Date is a very nice boat and very light but it is also very
> basic with no saloon and very little deck space, being mainly
tramp,
> one outboard, no anchor winch etc. It would be more appropriate to
> compare Rare Bird which weighs 3.7 tonnes empty because it has of a
> fitout more similar to a cat, though still only one hull fitted
out.
> My original comment was to say a proa with the same level of fitout
> doesn't have a huge weight benefit. Put the same fitout of the
typical
> cruising cat on a proa and it would be a dog and may not even
shunt.
> Proas need to be kept light so they can take advantage of their
> waterline length of the leeward hull and not bog down their fat
> windward hull. Keep them light and they are magic.
>
>
> >
> > The owner and I are working on tenders to build a 60' charter
proa
> > optimised to take advantage of the proa and unstayed rig
benefits.
> > The shell, bulkheads and beam materials are a touch under 2
tonnes
> > based on surface areas and laminates. This boat has 4 double
cabins
> > (2 with island beds) each with a toilet and shower, a huge
saloon and
> > covered deck space, plus enough cabin top to mount enough
solar panels
> > to power the electric motors. Ready to charter it will weigh
and
> > cost less than most 40' cats and outperform most 60 foot cats
> > according to the same spread sheet that accurately predicted
Blind
> > Date's weight,.
>
> That will be very impressive if it can be achieved.
>
>
> >
> > >Where a proa gets it's performance is in the extra
waterline length.
> > It's pretty pointless comparing proas with cats as they are
such
> > different beasts fulfilling different rolls.
> >
> > The harryproa role is cruising comfortably and safely for a
given
> > price . Most cat owners would say the same. Harryproas do this
> > extremely well. Look at http://www.youtube.
> > Has anyone sailed on a cruising cat at 15 knots boatspeed in
15 knots
> > wind speed in such comfort with such low stress? Mark Giles,
who has
> > test sailed a lot of cats (and one harryproa) for Multihull
World
> > magazine hasn't. The cat fulfills this role comparatively
poorly,
> > unless the comparison is with a mono.
>
> Rare Bird is a joy to sail as are all the Harryproas I have sailed
on.
> Nobody is disputing that.
>
>
> >
> > Waterline length is part, but not all of the story. Other
important
> > factors are:
> > The reduced drag from not having daggerboards and their slots.
> > Reduced weight and windage of superstructure that isn't
compromised
> > for rigging loads and daggerbboards.
> > All the weight concentrated in the middle of the boat.
> > Higher righting moment for a given weight.
> > More efficient hull beam to length ratios.
> > Better rigs.
> > Superior hull forms (no rocker, high prismatic) which are not
> > compromised for tacking.
>
> As I said, cats and proas are very different beasts. Harryproas
have a
> lot of great advantages which is why I like them so much, if I had
the
> money I would buy Rare Bird tomorrow.
>
> Speaking of which the estate is desperate to sell Rare Bird. Anyone
> interested in making an offer approaching $200,000 would land them
> selves an absolute bargain and own a very special boat.
>
> All the best and goodbye,
> Mark
>
>
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch format to Traditional
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe