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Date: Wed Sep 08 2004 - 15:51:30 EDT
My recent Catalina 27 had 15HP which drove us in all conditions without much trouble. OTOH, most boat builders since the late 70s really started to cut cost - to stay in business for one thing - and thinner fiberglas and smaller engines were 2 areas that were there for them to economize with. The result is underpowered boats out the door. This probably isn't true of *all* manufacturers but many certainly took this route. The Catalina 30 is one case in point - some were delivered with a 2 cylinder, 11 hp engine! There were also some larger engines available but some people were stretching their budgets to buy the C30 and customers need to economize sometimes also.
I think you're being very realistic to be thinking about an engine that will keep you off a lee shore in a blow - and I've watched a Catalina 30 give up after trying 4 or more times to get into a slip when the wind was around 15-20 knots! He tied up at a finger pier until the wind died. His engine just didn't have the umph! to muscle the boat into the slip. I'm sure there are some books with informations regardless HP:weight ratios - I'll look thru my library of stuff and see what I can find.
OK, looked thru several books -- didn't find a formula for selecting an engine - I guess it's complicated by the fact that some sailors don't use *any* engine and sail for years and years. There is a formula somewhere - it has to do with LWL, wetted area, required speed (based on hull speed) - and this is a biggie - the extras that are on the engine like alternators, etc. Also, the power load on the engine will have an affect on the size needed.
If I find anything else I'll send another note ---
Sincerely,
Larry T
----- Original Message -----
From: Baumgart, James
To: ''
Sent: Wednesday, September 08, 2004 2:33 PM
Subject: RE: [world-cruising] Engine HP 'v' displacment
Interesting to note that my Catalina 25 fully loaded with an 8 HP Honda
outboard comes in at 812 lbs/hp. The boat is highly maneuverable under
power and sail. Normally I use less than 1/3 throttle to power at 5.5 knots
while getting 10 to 15 miles per gallon. 4 HP would be adequate for most
needs. I sail whenever possible, when the air is too light I am almost
always am motorsailing for even more fuel efficency.
A lot depends on underbody. A light displacement fin keel boat with
balanced rudder maneuvers easily. A full bodied, full keel boat with skeg
hung rudder won't maneuver around docks easily and will be hard to back up
regardless of HP. Just imagine adding an 11 foot bowsprit like on a
Westsail. However, in this case a badly underpowered boat would be a
nightmare. Learn to use springlines and always have anchor and sails at the
ready.
Also consider the prop. If you want to slow speed maneuver, motor, backup,
and so on get a regular 3 bladed prop. If you want to sail, a 2 bladed or
folding prop will improve performance under sail at the cost of losing a lot
of reverse thrust.
At least on my little cruising boat, I can pull the motor out of the water
when sailing and flush with fresh water when not in use. Also, having a
motor you can steer is a blessing, especially in reverse. I routinely sail
into and out of my slip just for practice.
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