Association Forum - Fuel consumption

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

Fuel consumption

New Topic

Topic Locked

Printer Friendly

Author

Topic

NCBrew
Captain

Member Avatar

USA
338 Posts

Initially Posted - 03/29/2016 : 12:27:44

Can anyone tell me the number of gallons a 9.8 HP Nissan burns on a Catalina 25 per hour. Open throttle at about 5 or 6 knots.

1998 Catalina 250WK
Ravaging
Albemarle Sound,NC

I spent most of my money on boats and beer, the rest I just wasted.

DavidBuoy
Admiral

Members Avatar

USA
707 Posts

Response Posted - 03/29/2016 : 13:14:09

I think when I clocked mine on a decent trip motoring i was either 1/8 or 1/4 gallon an hour. That's with my 6hp, probably about 4.5kts. Probably was 1/4gal/hr.

Captain Rob & Admiral Alyson
"David Buoy"-1985 C25 SK/SR #5053

jduck00
Captain

Members Avatar

USA
313 Posts

Response Posted - 03/29/2016 : 13:36:40

I have an older Yamaha 9.9 high thrust and it burns about 3/4 gallon an hour at 3/4 throttle. I hit 5.5 knots at 3/4 throttle. Not much increase in speed if I open it up.

Jeremy Duck
The Lucky Duck
1980 SKSR Hull # 1850

cshaw
Captain

Members Avatar

USA
460 Posts

Response Posted - 03/29/2016 : 17:23:51

quote:
Originally posted by jduck00

I have an older Yamaha 9.9 high thrust and it burns about 3/4 gallon an hour at 3/4 throttle. I hit 5.5 knots at 3/4 throttle. Not much increase in speed if I open it up.

I have a Johnson 9.9 on Confetti, and get about the same as you are getting

Chuck

Chuck Shaw
Confetti
Cat 25, hull#1
1976 FK/TR

Stinkpotter
Master Marine Consultant

Members Avatar

Djibouti
9080 Posts

Response Posted - 03/29/2016 : 18:42:50

"9.8" indicates to me the 4-stroke. I'd say 3/4 GPH is reasonable to expect at a cruising speed of 5 - 5.5 knots. However, you won't really benefit from wide-open throttle. By the time you reach the "theoretical hull-speed" of 6.3 knots for this boat, which should be at less than wide-open throttle, you're causing the stern to squat, drawing a larger wake, and burning way more fuel than the additional half knot or so justifies. You can reach higher than 5.5 knots, but above that your MPG will drop. And that last quarter-or-so of your throttle won't make the boat go any faster (unless a scuzzy bottom has been holding it back).

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

NCBrew
Captain

Members Avatar

USA
338 Posts

Response Posted - 03/30/2016 : 00:44:59

quote:
Originally posted by jduck00

I have an older Yamaha 9.9 high thrust and it burns about 3/4 gallon an hour at 3/4 throttle. I hit 5.5 knots at 3/4 throttle. Not much increase in speed if I open it up.

Wow! Thats 18 miles per gallon for Davidbuoy and 7.3 MPG for Jduck.
Anyone else with numbers?

1998 Catalina 250WK
Ravaging
Albemarle Sound,NC

I spent most of my money on boats and beer, the rest I just wasted.

Steve Milby
Past Commodore

Members Avatar

USA
5902 Posts

Response Posted - 03/30/2016 : 04:41:13

quote:
Originally posted by NCBrew

quote:
Originally posted by jduck00

I have an older Yamaha 9.9 high thrust and it burns about 3/4 gallon an hour at 3/4 throttle. I hit 5.5 knots at 3/4 throttle. Not much increase in speed if I open it up.

Wow! Thats 18 miles per gallon for Davidbuoy and 7.3 MPG for Jduck.
Anyone else with numbers?

I have a 6 hp Nissan 4 cycle engine on my Cal 25, and I haven't carefully checked it's fuel consumption, but I think a fair estimate would be about 1/4 gal per hour. The fuel stinginess of some of the small 4 cycle engines is really remarkable.

Steve Milby J/24 "Captiva Wind"
previously C&C 35, Cal 25, C25 TR/FK, C22
Past Commodore

DavidBuoy
Admiral

Members Avatar

USA
707 Posts

Response Posted - 03/30/2016 : 04:43:44

I may have done less than 4.5kts but i believe it's close. It was from about a 5 hour sample motoring into the wind. Definitely surprised me as I brought a reserve 5 gal canister in addition to my standard 3 gal and fully expected to use it. Did not end up needing it at all. I could've been running with the tide which would've required less throttle to maintain speed.

Captain Rob & Admiral Alyson
"David Buoy"-1985 C25 SK/SR #5053

Stinkpotter
Master Marine Consultant

Members Avatar

Djibouti
9080 Posts

Response Posted - 03/30/2016 : 10:16:26

Single-cylinder, 4-stroke, 6hp motors with no alternators definitely can get better mileage than the bigger 8-10 hp twins with alternators--especially at lower speeds. And a 6 can move a C-25, although I'd feel better about being in nasty seas and winds, making 5.5 knots to get to shelter, and maneuvering around a slip with the high-thrust, extra-long Honda 8 I had (the same engine as the current Honda 9.9). It depends on the conditions you expect and the way you plan to use the motor.

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

Voyager
Master Marine Consultant

Members Avatar

USA
5376 Posts

Response Posted - 03/30/2016 : 17:01:57

Does that mean you can get 20-25% better mileage by not running the alternator under load? While I don't suggest anybody disconnect their alternator from the battery while the motor is running(which would damage the alternator), you could disconnect the alternator lead before starting the motor. That would mean you'd have to use the pull-start rope to start the engine.

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

JanS48
Navigator

Members Avatar

USA
144 Posts

Response Posted - 03/31/2016 : 01:35:51

You folks are getting better mileage than I, in the spring and again in the fall I make a 12 mile trek up the bay to the storage yard. My 15 HP Mercury burns 2 gallons on that trip, but it's pushing between 6 ~ 6.3 k at approx. 3/4 throttle.
In reading the other posts, I do notice the stern squat mentioned and a slight mound of water behind the boat.
Reading between the lines, I guess I'd get better mileage holding the speed to a little over 5 k.

82 C25 SR FK
Sailing out of Newport Harbor.

Stinkpotter
Master Marine Consultant

Members Avatar

Djibouti
9080 Posts

Response Posted - 03/31/2016 : 06:16:49

quote:
Originally posted by JanS48

Reading between the lines, I guess I'd get better mileage holding the speed to a little over 5 k.

Yup--at slightly above 6 knots, no matter how hard the engine pushes, the water pushes back just as hard unless you have enough power to get the hull to climb over its bow wave (go partially on plane). I think you'll find 5.5 k to be more efficient and quieter. But is your Merc a 2 or 4 stroke? That also makes a difference. And a 15 is not going to match a 9.9 or 8, which already have some "reserve power"--you have a lot more.

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

Dave5041
Former Mainsheet Editor

Members Avatar

USA
3758 Posts

Response Posted - 03/31/2016 : 07:05:27

It has been a while since I checked it, but at about 4.5 kts it was around 3/8 gal/hr (1.5 quarts). I used less than the 3 gallons I bought over the winter. When my son was living at home he once complained that he put more gas in the snowblower than I put in the boat.

Dave B. aboard Pearl
1982 TR/SK/Trad. #3399
Lake Erie/Florida Panhandle

NCBrew
Captain

Members Avatar

USA
338 Posts

Response Posted - 06/02/2016 : 08:30:59

quote:
Originally posted by NCBrew

quote:
Originally posted by jduck00

I have an older Yamaha 9.9 high thrust and it burns about 3/4 gallon an hour at 3/4 throttle. I hit 5.5 knots at 3/4 throttle. Not much increase in speed if I open it up.

Wow! Thats 18 miles per gallon for Davidbuoy and 7.3 MPG for Jduck.
Anyone else with numbers?

And Dave 5041 gets 12 MPG?

1998 Catalina 250WK
Ravaging
Albemarle Sound,NC

I spent most of my money on boats and beer, the rest I just wasted.

Dave5041
Former Mainsheet Editor

Members Avatar

USA
3758 Posts

Response Posted - 06/02/2016 : 14:52:30

It is pretty amazing. I fill a 3 gallon tank at the beginning of the season. I fill the second 3 gallon tank when the first gets to about !/2 or I'm leaving on a longer trip. I don't usually buy any more gas unless I motor a lot on a cruise.

Dave B. aboard Pearl
1982 TR/SK/Trad. #3399
Lake Erie/Florida Panhandle

DavidBuoy
Admiral

Members Avatar

USA
707 Posts

Response Posted - 06/02/2016 : 16:53:38

So I just took some measurements. After four hours of motoring at 5.5-5.8kts I burned a little under 3/8 gallons an hour. This was pushing pretty hard to avoid a storm into the current and swell. Engine is tohatsu 6hp.

Captain Rob & Admiral Alyson
"David Buoy"-1985 C25 SK/SR #5053

Akenumber
Navigator

Members Avatar

USA
247 Posts

Response Posted - 06/02/2016 : 18:27:39

On a trip from San Diego to oceanside our 8.0 merc 2 stroke used a little over .5g an hour. And that was in rough seas and a stressful trip out of oceanside were I forgot I was wide open for about a half hour. Total of 8 hours motoring. For our next trip I will calculate that .5 and add some reserve. We also have an alternator, not sure it works all that well.

Ken
San Diego
84 C25 SR/FK 4116
The KRAKEN

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.