The PDQ 36 is a catamaran that was offered with either twin 10 HP
outboards, or twin Yanmar 2GM20's with saildrives (18HP). We chose
the diesel version, but about 2/3 were built with the outboards.
Actually, for those that had a choice, it was probably more like a
60/40 split.

The outboard versions are faster sailers because the the outboards can
be raised to eliminate drag, they weigh about 600 pounds less (the
actual difference is even larger because the diesel version got a lot
heavier fittings all around), and the weight distribution is better
with the outboards mounted a bit forward of the diesels. The
outboards are certainly cheaper initially, and have the maintenance
advantage of being easily removed. Last year we watched a sistership
on the next mooring replace an engine in an afternoon.

On the other side of the equation, although my diesels sail a knot
slower (its still faster than most monohulls) it powers about a knot
faster. Although the 4-stroke outboards are pretty quiet at low
rpm's, at wot they are very noisy and there's no easy way to
soundproof them. Properly maintained, the diesels should last 4000
hours or more, but the outboards tend to cook in 1000 to 1500 hours.

The final factor for us was the need to generate power - we would have
had to install a genset to supply our needs, and that tended to even
out some of the issues. I've thought about it a lot over the years -
if I had to do it again I might live without the freezer, reduce the
electrical needs, add some wind and wind, and get by with a small
Honda genset and the outboards. But then I talk to sisterships who
carry two Honda's, and three outboards and I'm happy I have the diesels.

One more thing -
With the current cost of fuel, the diesel has an added advantage.
Powering 100 hours a year, diesel would cost about $250 a year.
Powering the same distance with gas, however, will cost more like $800
at today's prices. If your need is to power out of the slip, the
outboards are fine. But a trip down the ICW will cost a lot with gas.

Correct, the earlier 2 GM are raw water cool.
Both of my friend have 1982 Yanmar 2 GM that are raw water cool.
BTW. my raw water cool 1982, 1 GM Yanmar was used in sea water all these
years. That is from May to October of every year and winterized with
antifreeze. Now it is completely disassemble and it does not show signs of
rust damages.
The yearly replacement of the internal zinc anodes in the engine and on the
propeller shaft may have something to do with it.
The Yanmar International Rep. stated that the 1 GM raw water cool Yanmar
(6.5 HP) was introduced for use in fresh water mainly the great Lakes. The
more recent 10 GM Yanmar is designed to produce 10 HP at 3300 RPM's.
Correct me if I am wrong but I hear that this 10 GM may be on its way out to
be replaced by the new fresh water cool Yanmar 2YM15 producing 13 HP at 3400
RPM's. Other manufacturers are rating their engine at 3000 RPM. Westerbeke
are rating their 12 C, 12 HP at 3000 RPM.

"Jeff" wrote in message
...
Mic wrote:
On Tue, 06 Sep 2005 16:07:59 GMT, "Denis Marier"
wrote:


Thanks for the information.
I'll search the net for one used 2 GM.


The 2 GM is "fresh water cooled" and the 1GM is raw water cooled...

I believe both fresh and raw versions of both were built. Its true
that most 1GM's are raw, but the 2GM has many of both types. The
engine name has an "F" in it (as in 2GM20F) it is fresh water cooled,
i.e. it has a heat exchanger.

Interesting, I always wondered why they made such a small engine for
use on boats of this size.

It seems like the YM's are destined to replace all of the GM's, but I
think the 1GM is still being sold.

The GM and YM series (and others) are rated at or about 3600 RPM.
I've always felt that 3000 is a reasonable cruising rev for my 2GM's,
but a friend who repowered with a 3YM says that everyone has told him
to run all day at 3400 to 3600.


Denis Marier wrote:
Correct, the earlier 2 GM are raw water cool.
Both of my friend have 1982 Yanmar 2 GM that are raw water cool.
BTW. my raw water cool 1982, 1 GM Yanmar was used in sea water all these
years. That is from May to October of every year and winterized with
antifreeze. Now it is completely disassemble and it does not show signs of
rust damages.
The yearly replacement of the internal zinc anodes in the engine and on the
propeller shaft may have something to do with it.
The Yanmar International Rep. stated that the 1 GM raw water cool Yanmar
(6.5 HP) was introduced for use in fresh water mainly the great Lakes. The
more recent 10 GM Yanmar is designed to produce 10 HP at 3300 RPM's.
Correct me if I am wrong but I hear that this 10 GM may be on its way out to
be replaced by the new fresh water cool Yanmar 2YM15 producing 13 HP at 3400
RPM's. Other manufacturers are rating their engine at 3000 RPM. Westerbeke
are rating their 12 C, 12 HP at 3000 RPM.

Yes, the 10GM are been sold. What I hear is they will not issue working
orders to produce more 10GM. The difference in price is $6600.00 CAD for
the 10GM and $7200.00 CAD for the 2YM15.
If someone shows up with a large blanket order for the 10GM they may change
their production. I do have any proof of that but some people stated that
they were quoted $6500.00 CAD for one 2YM15. At this time, the lowest I
got was $7200.00 CAD.

"Jeff" wrote in message
...
It seems like the YM's are destined to replace all of the GM's, but I
think the 1GM is still being sold.

The GM and YM series (and others) are rated at or about 3600 RPM.
I've always felt that 3000 is a reasonable cruising rev for my 2GM's,
but a friend who repowered with a 3YM says that everyone has told him
to run all day at 3400 to 3600.


Denis Marier wrote:
Correct, the earlier 2 GM are raw water cool.
Both of my friend have 1982 Yanmar 2 GM that are raw water cool.
BTW. my raw water cool 1982, 1 GM Yanmar was used in sea water all these
years. That is from May to October of every year and winterized with
antifreeze. Now it is completely disassemble and it does not show
signs of
rust damages.
The yearly replacement of the internal zinc anodes in the engine and on
the
propeller shaft may have something to do with it.
The Yanmar International Rep. stated that the 1 GM raw water cool Yanmar
(6.5 HP) was introduced for use in fresh water mainly the great Lakes.
The
more recent 10 GM Yanmar is designed to produce 10 HP at 3300 RPM's.
Correct me if I am wrong but I hear that this 10 GM may be on its way
out to
be replaced by the new fresh water cool Yanmar 2YM15 producing 13 HP at
3400
RPM's. Other manufacturers are rating their engine at 3000 RPM.
Westerbeke
are rating their 12 C, 12 HP at 3000 RPM.

wrote:
I got the engine for $2000 "as is" and it turned out to be in good
shape although I expected it to be worse.
When I sold the 1 GM, I really didnt know what it was worth and didnt
want oto hassle with people getting it and then for one reason or
another being unhappy so I advetised it on the internet for $450. My
phone rang like crazy and a guy drove all the way from New Orleans (450
miles) to get it.
Maybe I just got lucky.
We also have no diesel repair places nearby so I expected to have to
sorta "shade tree" it . Its only a diesel, not rocket science. (Gawd,
how many times have I said stuff like that and been wrong)

My story:

I picked up a used 3GM30 for $2700 USD. It had about 500
hours on it and I got to see it running in the boat with my
mechanic present. It ran well.

The owner said he was selling it because it didn't develop
enough power for the boat and had already ordered the next
size up Yanmar.

My mechanic asks the owner what RPM he runs it at? "Oh,
about 22-2300 RPM. I don't like to stress the engine". My
mechanic replies, "But with these engines you have to run
them at closer to 3000 RPM to develop enough power". I'm
ready to STRANGLE my guy so he doesn't screw the deal up.

I installled it this summer, on a catamaran that had only
outboards. It took about a week of part time effort (lots
of other projects on the go at the same time) to get it in,
including shaft installation and all engine auxiliary
services like fuel/cooling/exhaust, etc.

I'm fairly handy but it's not rocket science. If your
average boatyard guy can do it, why can't you?

Evan Gatehouse