Joe,

I for one really have an affinity for outboards.

Our 34 footer at aprox 6 tons, powers extremely well with outboards.
We are looking at doing a 40 footer, and at 11 tons, she will also have
outboard power as standard, with optional diesels.  We expect to see
the same advantages of outboard power vs diesel, namely more storage,
significantly quieter underway, and less maintenance.  We lose out
about 25% efficiency with outboards vs diesel.

One thing you have to remember though is that our Buzzards Bay cats are
designed to cruise at high speeds, (up to 30 knot's), have a very
focused build to eliminate excess weight, and are not designed to cross
oceans.  They are robust, and are excellent coastal cruisers however.
We build boats not to compete with Nordhavn or Krogen, but with Sabre,
Tiara, and MJM.

It's a bit of a different game when you step up to 50 feet.  If your
goals are a heavy cruiser with a ton of space and range and only wish
to cruise up to 20 knot's, then I think perhaps outboards would be a
needless experiment and you will run into resale value issues.  I don't
even want to think how you would prop it...? If however, you think you
can get by with 45 feet, and are dedicated to keeping her light and are
looking for express cruiser performance, then a pair of the big Yamaha
350 v8's might do the trick.  I guess we just need to learn more about
your needs before anyone of us can say that this is a good idea or not.

For yourself and for anyone else that may find this helpful, here is a
comparison of positives and negatives of outboard vs diesel power we
have learned over the years on our Buzzards Bay's.

Advantages of outboard powered Buzzards Bay 34's
1)Smooth and Quiet
Powered by outboards, our Buzzards Bay 34 is one of the quietest power
boats built.  This has got to be the outboards biggest advantage.  Most
of you have never been on a truly quiet motor boat, and believe us,
once you have, you'll find you have very little tolerance for the noise
and vibration that is typical of powerboats.
2) Low Maintenance
With the ability to completely tilt out of the water, outboards
completely avoid the growth and corrosion issues that make up the
majority of maintenance of submerged drive systems.
3) Increased Storage
On outboard powered Buzzards Bay 34's, the space in the hulls under the
cockpit that would normally be taken up with engines and exhaust
becomes wide open storage space.

Advantages of diesel stern drive powered Buzzards Bay 34's
1)Joy Stick Control Maneuverability
Buzzards Bay 34's powered with Mercruiser-Cummins Axius drives have the
advantage of joy stick maneuvering, much like the popular IPS (Volvo)
and Zeus (Mercruiser-Cummins) systems.  This option makes for low
stress docking.  The twin counter rotating propellors of Volvo or
Mercruiser-Cummins stern drives have greater propellor blade area than
the props on outboards, and as a result, the diesel powered Buzzards
Bay 34's are more easily maneuvered than outboard powered vessels.
2) Increased Efficiency and Range
As fuel efficient as todays outboards are, diesel stern drives will
always be more fuel efficient.  The difference is about 25%.  Fuel
capacity of both diesel and outboard powered Buzzards Bay 34's are the
same, so range is increased by 25% as well.

Joe, feel free to contact me directly to discuss this further.

Russell Hunt, President
Multihull Development, Inc. and Buzzards Bay Catamarans
Office #: 508-403-0301
Cell #: 508-759-4111
Email us at: info@MDcats.com
Check out our website at : www.BuzzardsBayCats.com
http://www.yachtworld.com/multihulldevelopment/

Russell,

Thanks for the insights.  As a builder, how do you adjust for the weight
distribution between inboard diesels and outboards?  Two Yamaha 350's
represent about 1,700 lbs hanging off of your stern.

Do you have to adjust the hull design or interior configuration to maintain
trim?

Bob Deering
Juneau, Alaska