Even in  Beebe's book,"Voyaging Under Power", the bible of the power-only
crowd, his vessel, "Passagemaker", was a motorsailer, albeit smaller rigged
than he really wanted. Many of the examples he offers as prime passagemakers
are instead prime coastal cruisers, 'semi-displacement' hulls not optimized
for long passages, but rather coastal cruising, where rapid transit is a
primary requirement, while fuel use and surviving ultimate conditions are
secondary considerations. 'Trawlers' today are gravitating toward these
semi-planning hull configurations, and twin engines, as buyers become
reluctant to accept slow 7-9 knot vessels. And forget wide appeal of
primarily
sail-powered vessels, particularly with our aging population, so how about
those old versatile motorsailers.

We don't hear much of motorsailers these days....not a popular subject. The
old traditional, stoutly-built vessels, with a hefty engine(s), were
necessarily compromised in both their sailing and powering statistics. Let's
modernize the motorsailer. The multihull planform holds great promise to
improve this breed. The long slender hulls of the catamaran vessel have
proven
real efficient to push under both power & sail.....not only efficient, but
not
limited to the traditional slow displacement/length hull-speeds. Just what
the
motorsailer needs....far less compromising increases in both sail and power
performance, while maintaining an economy of operation that truly allows a
sea-kindly, long-range capability.

Let's explore a 40' example. Take the single 120-140 hp diesel used to push
the conventional 40' single-hulled trawler or motorsailer to a maximum 8.3
knots hull speed and divide it into two smaller 60 hp diesels driving two
long
slender catamaran hulls. Voila!, maximum to 15 knots under power with the
reliability of twin engines and the stability of a twin-hulled vessel. Add a
modest sailing rig to these easily driven hulls, and you now have a
passagemaker capable of cruising 12 knots under sail/ power compared with
those older 7-knot boats. With 12 knots of speed at your command, you can
really take advantage of 'weather windows' to:  1) make your passage as
smooth
as possible,  2) make some lengthy passages you might never have considered
in
a slower boat. This multihulled vessel will likely be slowed less by an
obstructive seaway, and will accordingly make a passage at almost twice the
average speed of the single-hulled vessel...twice the speed for the same
total
HP. There is an economy of operation here that cuts fuel requirements and
bills, and greatly extends their range. In light airs, running one engine
often is all that is needed to bring the apparent wind up to make the sails
work harder, and the combination provides much better results than either
motoring or sailing alone....

....sailing synergy/harmony, the motor taking over in the lulls and the rig
taking over in the puffs.

------ Original Message ------
From: "Tradesure" tradesure@libello.com (by way of Georgs Kolesnikovs)

Many of these boats could not sail nor motor very well, as we always
said, real dogs in all conditions, but they still sold.

Reply to Brian Eiland.

Brians choice of 12 knots is a significant figure for me. When the Cordova
was launched back in 1984 the owner declared that he had a "target" speed of
12 knots. He wanted to average 12 knots under whatever combination of
sailing/motoring and motor sailing that was necessary to achieve this. Some
15 years and over 100,000 nautical miles later and numerous crossings of the
oceans of the world,, he told me that he had failed. He had only managed an
average of 11.8knots over all that time! Knowing how difficult it is to
maintain high average speeds for such immensely long distances I must say
that I think he succeeded admirably.I think most of us would be happy to
fail by 0.2 of a knot.

Regards,

Malcolm Tennant.

Malcolm Tennant Multihull Design Ltd
PO Box 60513 Titirangi,
Waitakere 0642
NEW ZEALAND

ph +64 9 817 1988
fax +64 9 817 6080

e-mail malcolm@tennantdesign.co.nz
www.tennantdesign.co.nz
www.catdesigners.com