Thanks....you've given me a number of considerations that hadn't occured
to me....fuel storage...theft...etc.
On the other hand, some things aren't a factor, such as a windvane.
Thanks again.
Norm

On Thu, 12 Feb 2004 23:21:56 -0500, rhys wrote:

OK, I've got an old 33 footer powered by an Atomic 4...currently in
rebuild mode. Trust me...I've thought of this.


I'm looking for a boat to enjoy upon retirement this May. Being poor,
I'll have to settle for an older boat, 30-32 feet. I've seen a number of boats
in my price range on my list, but have rejected the ones with an OB. But
then I got to wondering...should I do so?

Not necessarily. There's snob appeal and esthetics at work as much as
considerations of efficiency.

The advantage of an OB is cost, doesn't take up interior room, at least
semi-reliable these days. But then I wonder about enough power in a
seaway.

A 15- to 20 HP fourstroke OB iss as powerful as you'd need. Most 30 HP
direct drive IBs put out 17-18 HP at the prop. Speaking of the prop,
you'd want a special one for an OB on a sailboat with a maximum hull
speed of 7 knots (30-32 feet). You want something with bite, not
speed.


The area I plan to sail (San Juan Islands) is quite sheltered....
wind chop, but seldom any significant swells. A safe haven is rarely more
than 4 - 5 hours away.

Well, if you are sailing most of the time, there's no real issue then.

So what am I missing, or haven't thought of, as regards to OB power?

Things to consider: Where does the gas go? Is the OB permanently hosed
and wired to a control lever near the helm? Does your transom "suit"
an OB? Canoe sterns generally don't, for instance.

The looks of the thing...do you care?

A 15 HP 4-stroke OB is well over 100 lbs.: can you lift it off for
storage? I'll bet a thief and his buddy can.

Advantages: ease of access, reliability, transportability, easy to get
gas, can be lifted clear of the water while sailing, reducing drag.
Can conceivably be used fixed or pivoting, making docking a lot
easier. Rapid response. Can be transferred to a (largish) tender, like
a 10 foot RIB, which is perfect for a 15 HP. Easy to unfoul the prop.
Easy to maintain and get semi-cheap spares. Possible to hand-start.

Disadvantages: Easy to steal, easy to swamp in a seaway, gearing and
prop usually not ideal for sailboat speeds, although this can probably
be remedied, not ideal for prolonged use like Atomic 4s or diesels,
not great with charging batteries, running lights, etc. May interfere
or preclude windvane steering.

I put these points forward for debate, not as uncontestable.
Personally, I think an OB can work on a 30 foot or more boat, but I
usually see them on nothing bigger than a 27 foot C&C that's stripped
for racing. Must be a reason for that....

However, when my Atomic 4 overheated on a cruise in 2000, I was able
to lash my 10' Zodiac to the side of my five ton cruiser and use the
10 HP 1985 Honda 4-stroke to drive the boat at 4 knots for several NM
until we got to our home port. So, yes, it can be done. Burnt a lot
more gas than usual, however G.

R.