Economical Cruising on C-Dory's

Thanks Jay (and others too...),

I've been enjoying the narrative and pictures of your latest Southeast AK trip; a Great area for sure! Current plans call for us to go back to Southeast next summer. We may even leave Naknek on her trailer in Wrangell for subsequent summer boating seasons (...that's still on the drawing board). The only downside with that is it would preclude trips to Powell ... dang.

I agree with you - I probably wouldn't want to cruise in a C-Dory without sufficient power to get Naknek on plane. Cruising at displacement speed is very enjoyable (and I TOTALLY agree with you regarding autopilot...), but having the power to push her on plane is very good as well - whether it's to "get there," run from wx, or whatever.

That said - I suspect when we eventually have to repower Naknek I'll look VERY seriously at going with the twin engine configuration. Inspiteof a few downside issues (twice the moving parts, increased lower unit drag, etc.) having the option to displacement cruise Very economically, yet still get up on plane when wanted, is very appealing. Then there is the whole redundancy argument for twins. Who knows - somewhere down the road somebody may even offer smaller 4-strokes with a counter-rotation option (...dream-on Casey!)

Happily, with only 540 hours on the Suzi it should be a Long time until we have to make a choice. ...but it's fun to think about!

Casey
C-Dory Naknek
 
Jay, My appologies for the name mixup. Thanks for the information. I certainly agree that for any length of trip in a CD 22, (or any of the C Dory boats thus far) a speed faster than pure hull speed would be very desirable and one of the reasons we purchased a C Dory.

Great log--sorry we didn't make it this summer--hopefully next summer!
 
While most of this discussion has been efficient cruising at hull speed, I tend to cover greater distances with some time constraints. So I am more concerned with the most efficient speed to travel quickly. I've had the lucky or unlucky situation of trying two different engines on the same boat. Both engines operated most efficiently at the same speed, between 22 and 24 mph. If I go slower mileage goes down or if I go faster the same thing occurs. On my current motor I see about 4.2+ mpg at 24 mph.

So when looking cover distance, I'll be looking to operate right at that speed.

Tom
 
tpbrady":17n5pq6o said:
While most of this discussion has been efficient cruising at hull speed, I tend to cover greater distances with some time constraints. So I am more concerned with the most efficient speed to travel quickly. I've had the lucky or unlucky situation of trying two different engines on the same boat. Both engines operated most efficiently at the same speed, between 22 and 24 mph. If I go slower mileage goes down or if I go faster the same thing occurs. On my current motor I see about 4.2+ mpg at 24 mph.

So when looking cover distance, I'll be looking to operate right at that speed.

Tom
Click to expand...

Exactly what I have found in my travels. The most ground covered for the least fuel & time savings is 22 mph (pretty easy to remember on a CD-22). 4 mpg on the nose in my case (I'm heavilly loaded (no, not with Wild Turkey).
 
Well, that 4-4.2 figure at speed is certainly a plus for the 22s. Our 25, heavily loaded, gets more like 2-2.3 at speed. At hull speed (mostly), we've seen as good as 3.5 mpg. We put in a fuel flow meter last week... interesting to have that info staring you in the face... wasn't sure I wanted to know after seeing the gallons tick away. :shock: I'm hoping it will help us find the best trim/speed for economy.

This has been an interesting discussion - thanks!

Best wishes,
Jim B.
 
This is a very interesting thread. Seems to me the boating industry puts size and speed above fuel efficiency even with rising gas prices. The (now defunct for legal and not boat issues) Cape Cruisers are a good example. They made a 23 to out-do the CD22 and a 26 to out-do the CD25 both bigger boats and with a deeper Vs (I think) so they needed bigger engines.

Another of my favorite boats, the Albin family cruiser, started as a 25 footer with 21hp (later 35) then a 27 footer with 65 hp (later 100). Now the family cruiser is 30 feet with 265 hp (optional 315). It seems obvious to me that the industry is looking at a different market than in the past. I think they make more money on big boats sold to the upper class than small ones to people who worry about gas prices.

Sadly C-Dory is very much in the same boat(!). Each boat they come out with seems to be bigger than the last. It's nice that they've kept the smaller boats in production; but they sell for such a premium. The idea of spending $10k extra to get better fuel efficiency (you can buy a lot of gas for $10,000) doesn't make much sense. Maybe when gas is $15 a gallon...

I'm impressed with the selection of small low-power boats available in the UK. I wish some were available here.

carl
 
Definately correct--the only way to go more fuel effecient is to go with pure displacement hulls, with small diesel engines--something that the Scandinavians do very well--many are wooden lapstrake 20 to 25 foot boats which have 8 hp to 20 hp diesels. The more "modern" are fiberglass, but similar hull lines--narrow beam, and good flow.

The semi dory is a pretty good compromise however. The semi dory is a hulll which does well at displacement speeds, but still will go fast and be seaworthy. These european boats will not go fast. Add in that the Tom Cat gets 50% better than I got in a deep V the same size, with the same hp. If you really want the effeciency, go with the long wave piercing cats--very light weight.

Look at the trawlers--they have gotten fatter and heavier--to put more "stuff" on board--and that is why the Nordhavn 47's only got 1.2 to 1.6 miles a gallon a slow ocean passage, vs a long narrow boat with low hp which will get 5 to 8 miles a gallon.
 
This has been a very interesting thread and one I think about a lot. We are all in our situations for different reasons. Last year I bought a ranger 21' tug for reasons different than fuel economy and now find myself wishing that I could pay a little more in fuel costs and travel a little faster.

I told the wife that I did not know that you could be on the water as much and have soo much fun for such a little cost. At about 1/3 GPH I am afraid that my 12 gallons of fuel will go bad before I use it up. How about that for a problem?

I am about to get used to the speed, and it is not hard to get used to the low costs. You have made good decisions to purchase C-Dorys and I may bite the bullet one day. Come up with to sped up a full displacment hull and I will have it made. Enjoy the boating.

Ron
 
We are running twin Yamaha 40's on a CD22 cruiser. Our load is probably somewhere in the middle range. We are generally more than just a day trip, but so far (unfortunately) we have not been able to get more than a long weekend. And I can't give a real numbers yet, to new. I too debated the twin vs single and then found a boat. That made the decision for me, it had twins. So for now I have learned that it is fun to cruise at hull speed (~5knots), it is quiet, lots of time to see around. And I have tried shutting one down, raising it up out of the water and it still controls fine, at least in quiet water, relatively close to shore. I believe this to be our most economical cruising attitude. Now I know a 40 is big for a kicker, but I don't think I want to be trying to make it home on a 5-10HP when I may be out in the Strait in moderate or more, wind, tide or current, or all three. (The redundancy issue again) But here is where the twins really shine. Both in the water and running, at hull speed and slower, they make for really fine directional control. Point 'em both straight ahead, no hands on the wheel and using the throttles, the boat goes where I want it to go. I think that is one advantage that makes twins sparkle in comparison to the single only or single and a kicker. That's my $0.02 worth.
Harvey
Sleepy C :moon
 
i'm a big believer in twins. haven't seen a twin towed in yet, although i'm sure it's happened.
several weekends ago, linda and i set out across lake cumberland for a 45 mile or so, one way, trip. boat handled well, although, there is a c-dory learning curve one must achieve for passing thru another boats wake, other than that, was a very enjoyable, well deserved, cruise. total miles traveled was approximately 90. had full tanks (40 total) when we started, and approximately 20 gallons when we arrived back at the home slip. averaged about 4.5 mpg, @ $3.68 per gallon = $73.60 overall expense.
one of our dock neighbors made the same trip this past weekend. his 38' cruiser, (regal) twin 454's averaging 1.6 gallons per mile cost him, 144 x 3.68= $529.92. ok, we've all heard the story, if you can't afford the gas don't buy the boat! i know exactly how this guy felt, my prior boat averaged 1.9 gpm, and a 320 gallon fill up weighed in at about $1177.60. loved seeing the expression on our guest face when they proudly stated, hey, let me pick up the gas today. i never accepted their offer, but it certainly was fun playing around with them.
regarding twins over single's, our other water source is the ohio river.
the river offers challenge, and it was the challenge that attracted me to boating. much commercial traffic, breakdowns, while in the channel is not a recommendation, last year a houseboat lost power and was ran over by a pusher, pushing 15 barges. four crew lost.
that's my story and i'm sticking to it!
whats yours?
pat
 
Revisiting an old thread.

Question about the tomcat and planning speeds. I am mostly always on plane when headed to a destination. We went to the San Juans this weekend using non ethanol gas and got there using less than 1/2 tank of fuel averaging around 22 MPH. We have no fuel flow monitoring so I have no idea what our MPG was while underway.

Once in the San Juans, our only option was to refuel on the return leg using Friday Harbors expensive Ethanol gas. Our return trip was at the same speed but we used more fuel overall. This is probably attributed to the fact that Ethanol gas returns less MPG than the pure gas.

QUESTION: If I was to try cruising at planning speed as many of the folks in this thread have discussed, would I see significant increase in MPG? The next question is whether I should just cruise on a single motor and raise the other (non operating) engine out of the water to reduce drag?
 
Revisiting an old thread.

Question about the tomcat and planning speeds. I am mostly always on plane when headed to a destination. We went to the San Juans this weekend using non ethanol gas and got there using less than 1/2 tank of fuel averaging around 22 MPH. We have no fuel flow monitoring so I have no idea what our MPG was while underway.

Once in the San Juans, our only option was to refuel on the return leg using Friday Harbors expensive Ethanol gas. Our return trip was at the same speed but we used more fuel overall. This is probably attributed to the fact that Ethanol gas returns less MPG than the pure gas.

QUESTION: If I was to try cruising at planning speed as many of the folks in this thread have discussed, would I see significant increase in MPG? The next question is whether I should just cruise on a single motor and raise the other (non operating) engine out of the water to reduce drag?
 
Just guessing, but you're probably getting about 2.5-3.0 mpg at 22 kts. Once inside the Island group you can save some fuel money cruising on one engine. We left the other engine down and in neutral. Steering becomes very hard when one engine is trying to fall off to one side as you turn. Ours wouldn't come completely out of the water anyway.

You'll be stuck at about 5-6 kts. but getting 5-6 mpg! I recall many TC owners telling of doing this. We would switch engines every hour. Where did you find non-ethanol fuel?
 
Dreamer":3bcq2ou3 said:
Just guessing, but you're probably getting about 2.5-3.0 mpg at 22 kts. Once inside the Island group you can save some fuel money cruising on one engine. We left the other engine down and in neutral. Steering becomes very hard when one engine is trying to fall off to one side as you turn. Ours wouldn't come completely out of the water anyway.

You'll be stuck at about 5-6 kts. but getting 5-6 mpg! I recall many TC owners telling of doing this. We would switch engines every hour. Where did you find non-ethanol fuel?
Click to expand...

Port of Everett has non ethanol fuel.
 
The 24 may be different than the 255. We found that with the liquid tie bar, that we also could not trim the other engine all of the way up, and had have good steering.

You do have to keep the speed down to less than 6 knots--and the 255 still drug a lot of water, because of the submersion of the wing deck--not really acting like a true displacement cat where the wing deck is well clear of the water.

When running with friends who had trawlers, we found it more comfortable to run at 20 to 25 knots for an hour, and then wait 3 hours for the friends to catch up with us while we anchored.
 
Nice to see this thread back. Interesting, and still timely topic.

A couple of weekend ago, I had a day to just take it easy on the way to Friday Harbor for the weekend. I left John Wayne Marina early and spent most of the day on a slow cruise (or as George would say "Range Expanding Mode"). Sorry I don't have any good numbers here, but it was worth it. the cruising was at 5 - 6 knots, just barely turning a bow ripple, and it covered all of twice my normal route to FH. The route included a course deviation from straight to Cattle Pass, for an hour out and around Hien Bank, then across the south end of Lopez and up the east side, south of Decatour, then between Decatour and Blakely and north of Shaw past Deer Harbor and then to Jones Island. In the morning I wandered out toward Roche, then turned and headed down the channel to Friday Harbor, to the fuel dock.

Nice surprise there because I put in almost the same amount as I would usually add after running headlong across from Sequim Bay to FH and making that trip in 3 hours. I had put about 9 hours on the meter, enjoyed the trip, saw lots of scenery, and didn't even come close to any "chunky" things floating about in my path. The slow cruise was with both engines down and running, around 16 - 21K RPM. Quiet, and relaxing.

Worth every minute.

Harvey
SleepyC:moon
 
in response to the initial post from 7 years ago...

the alternative cabin cruiser I looked at get less than 1mpg. So a fluctuation of 4-5mpg in our boat still makes me feel spoiled.
 
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