Mileage
 

JR Weiss wrote:
"Rick Cortese" wrote...

Slow in the group so I figured I'd waste some bandwidth. Checked the mileage
and my boat with an 18hp two stroke only makes 2-3 mpg. I figure it is mostly
because I usually go sailing with my son so WOT for 7-10 miles to get where
the winds are to his liking and same drill coming back after the winds die.

Just my guesstimate but we seem to make ~5 knots at 1/3 throttle and ~6 knots
at WOT. My GPS went down for the count so I have to get a new one before I can
get good data.

Is this about right for a hull that is in sore need of a bottom cleaning?


It appears you're wasting fuel at WOT. Is it really worth all that extra fuel
to save 20 minutes? I suspect you could get half the difference (5.5 kt) with
1/2 to 2/3 throttle. You might get double that by cleaning the bottom!

My SeaPearl 21 with a Honda BF2 4-stroke got around 45 mpg at 5-5.5 kt and 1/3
throttle. Half throttle got another 1/4 kt at the cost of a lot more noise.



Thanks for the info! I guess I should provide a bit more myself. In
strong winds my son will even have the motor WOT and calls it "Power
Sailing". He can't get more then an extra knot or two out of this
combination but I will admit it makes tacks go a little truer: Less lost
speed when crossing over and jib doesn't spin the boat quite as
much/over turn. Still an 18 hp 2-stroke hammering away at WOT while
under full sail is not my idea of a pleasent afternoon sail so I have to
do something to make sure that doesn't happen. Liable to have to tell
him the big motor slipped off the transom!grin

Your mileage makes me envious. Sounds like my best bet would be ~4-6 hp,
4 stroke, and maybe some kind of throttle restrictor plate. Actually I
don't mine what my son does when I am not on the boat so... Your post
made me think it isn't just about the money for gas but the range and
safety margin it would provide. Sheesh! I wouldn't want to carry a 50
gal drum of gas just to get a 50 mile range under power. Matter of fact
I have already turned in an order.grin

BTW: I read a review of the Honda and they echoed your high milage.
Something like one end of Anderson reservior to the other and back on
1/2 gal of gas. Probably WOT all the way and 10-15 miles.

Rick

Mileage
 

"Rick Cortese" wrote...

Thanks for the info! I guess I should provide a bit more myself. In strong
winds my son will even have the motor WOT and calls it "Power Sailing". He
can't get more then an extra knot or two out of this combination but I will
admit it makes tacks go a little truer: Less lost speed when crossing over and
jib doesn't spin the boat quite as much/over turn. Still an 18 hp 2-stroke
hammering away at WOT while under full sail is not my idea of a pleasent
afternoon sail so I have to do something to make sure that doesn't happen.
Liable to have to tell him the big motor slipped off the transom!grin

Motorsailing in light wind or to gain more windward advantage is a valid
technique. But again, you are simply wasting fuel by using WOT at ANY time the
sails are pulling! With the sails pulling at all, you will likely get the same
extra 1-2 kt and anti-stall coverage during tacks with 1/3 throttle!

You don't say how old your son is, but he is turning into an irresponsible
sailor. Wasting that fuel and dumping all that 2-stroke oil needlessly into the
water is ridiculous! Don't forget also that when the motor is on, REGARDLESS of
the sails, you are a POWERBOAT for ALL purposes of the COLREGS (Rules of the
Road)!


Your mileage makes me envious. Sounds like my best bet would be ~4-6 hp, 4
stroke, and maybe some kind of throttle restrictor plate. Actually I don't
mine what my son does when I am not on the boat so... Your post made me think
it isn't just about the money for gas but the range and safety margin it would
provide. Sheesh! I wouldn't want to carry a 50 gal drum of gas just to get a
50 mile range under power. Matter of fact I have already turned in an
order.grin

You can do even better by ensuring the motor you get is a "high thrust" or
"sailor" version. It will have a prop much more suited to the low speed range
of the sailboat, and will help you get near hull speed even against heavier
seas. I don't know if they are available in the 4-6 HP range, but I had a
Yamaha 9.9 on a previous boat that was specifically set up that way from the
factory. Also note that many/most 8 HP motors are identical to the 9.9
offerings from the same mfgr, except for the RPM limit (and maybe the
aforementioned carb or throttle restriction). The 9.9 on my old boat was
definite overkill (3500#, fin keel), but the $100 savings for the 8 HP that
weighed the same wasn't a good trade for the versatility. IIRC you said yours
is 5000# or more, so the 6 HP may be marginal in any weather...

Mileage
 

wrote:

The sea pearl 21 is NOTHING like your boat. It's an extremely light
boat and doesn't need nearly as much power to push it. You could
pretty much paddle it like a canoe.

But a good set of oars is MUCH better than a paddle! :-)


As for your son - he obviously needs a boat of his own. Buy him an old
aluminum semi-vee and give him that outboard you have now to power it.

I think I'd rather not have him near me on the water in a powerboat at all...

Mileage
 

JR Weiss wrote:
"Rick Cortese" wrote...
snip
You don't say how old your son is, but he is turning into an irresponsible
sailor. Wasting that fuel and dumping all that 2-stroke oil needlessly into the
water is ridiculous! Don't forget also that when the motor is on, REGARDLESS of
the sails, you are a POWERBOAT for ALL purposes of the COLREGS (Rules of the
Road)!

He's 35. I think I may try Salty's suggestion and give him my 120hp I/O
Larson bowrider. It has sat idle for a year and I have little interest
in it now. I'll give him the "Girls with tight butts in bikinis water
skiing" pitch and see if he buys it.


snip
You can do even better by ensuring the motor you get is a "high thrust" or
"sailor" version. It will have a prop much more suited to the low speed range
of the sailboat, and will help you get near hull speed even against heavier
seas.

Noted. Figure I need one weak high milage restrictor plate motor when he
goes with me and something I should have.grin

Rick

Mileage
 

On Sun, 14 Sep 2008 18:46:52 -0700, Rick Cortese
wrote:

Slow in the group so I figured I'd waste some bandwidth. Checked the
mileage and my boat with an 18hp two stroke only makes 2-3 mpg.

A more realistic measure would gallons per hour. Miles covered per
gallon is subject to too many variables - tides/current, wave height
and frequency, wind speed and direction, etc.

My boat, a 42' Moody, a substantially-built sailboat, uses around 1/4
- 1/3 of a gallon per hour. Distance covered in that time - anywhere
from 2 to 10 nautical miles.

Mileage
 

On Fri, 19 Sep 2008 08:08:43 +0100, Mike Pearce
wrote:

On Sun, 14 Sep 2008 18:46:52 -0700, Rick Cortese
wrote:

Slow in the group so I figured I'd waste some bandwidth. Checked the
mileage and my boat with an 18hp two stroke only makes 2-3 mpg.

A more realistic measure would gallons per hour. Miles covered per
gallon is subject to too many variables - tides/current, wave height
and frequency, wind speed and direction, etc.

My boat, a 42' Moody, a substantially-built sailboat, uses around 1/4
- 1/3 of a gallon per hour. Distance covered in that time - anywhere
from 2 to 10 nautical miles.

Yes, fuel useage on a boat is more commonly expressed in gallons per
hour. It can still be useful to express it in miles per gallon, too.
My boat, with a 4-stroke outboard uses roughly 1/2 gallon an hour at
full power. I keep a log book, and over the years, I've been able to
determine that my boat gets about 10 statute miles per gallon on
average when traveling on motor alone at around hull speed or a little
slower. Obviously, conditions will have an effect.