The performance data for the Venture 23 is up on C-Dory's website (finally), but something is amiss. If I calc the MPG numbers using their GPH and MPH data, they don't match the MPG numbers C-dory has in their chart. Any idea why they would publish bad data? Seems like a pretty big blunder...
Venture 23 data published on C-dory website
- Thread starter AK Angler
- Start date
I think there' more than one set of numbers that are wrong. Even if you do the math correctly, the MPG calculated from MPH/GPH is too high. For example,
24MPH/4.2GPH = 5.71 MPG
and
34MPH/7.5GPH = 4.53 MPG
No way that boat's going to get 5.71MPG at 24 MPH and 4.53 MPG wide open.
Not gonna happen even with a light load...
24MPH/4.2GPH = 5.71 MPG
and
34MPH/7.5GPH = 4.53 MPG
No way that boat's going to get 5.71MPG at 24 MPH and 4.53 MPG wide open.
Not gonna happen even with a light load...
Here is the table from the C-Dory site:
The fifth column is my calculation from their MPH divided by their GPH. You can see the discrepancy between this calculation and their MPG figure in the forth column.
Fuel Performance
Honda twin 50 four stroke. Fuel load 60 gals. Additional 700 lbs.
R.P.M. G.P.H. M.P.H. M.P.G. M.P.H./G.P.H. (calculated M.P.G.)
1000** 0.85** 2****** 9.2******* 2.4
2000** 1.5** 6.4***** 7.5******* 4.2
3000** 1.8** 12.2**** 6.5******* 6.7
3500** 2.5** 17****** 6.2******* 6.8
4000** 3.1** 19.8**** 5.8******* 6.4
4500** 4.2** 24****** 5.2******* 5.7
5000** 5.9** 28****** 4.9******* 4.7
5500** 6.3** 32****** 4.7******* 5.0
6000** 7.5** 34****** 4.1******* 4.5
*******In any event, these MPG figures seem awfully high for a 23 foot boat like the Venture 23, don't they? My recollection is that 4 MPG is a tough to achieve average figure for a CD-22! ???
Joe. :teeth :thup
The fifth column is my calculation from their MPH divided by their GPH. You can see the discrepancy between this calculation and their MPG figure in the forth column.
Fuel Performance
Honda twin 50 four stroke. Fuel load 60 gals. Additional 700 lbs.
R.P.M. G.P.H. M.P.H. M.P.G. M.P.H./G.P.H. (calculated M.P.G.)
1000** 0.85** 2****** 9.2******* 2.4
2000** 1.5** 6.4***** 7.5******* 4.2
3000** 1.8** 12.2**** 6.5******* 6.7
3500** 2.5** 17****** 6.2******* 6.8
4000** 3.1** 19.8**** 5.8******* 6.4
4500** 4.2** 24****** 5.2******* 5.7
5000** 5.9** 28****** 4.9******* 4.7
5500** 6.3** 32****** 4.7******* 5.0
6000** 7.5** 34****** 4.1******* 4.5
*******In any event, these MPG figures seem awfully high for a 23 foot boat like the Venture 23, don't they? My recollection is that 4 MPG is a tough to achieve average figure for a CD-22! ???
Joe. :teeth :thup
starcrafttom
Active member
joe your numbers look better then their numbers in most cases. The cc is a wider boat with should provide more lift, but those are still really good numbers and the boats must be light. You have to remember that most of us have a LOT of weight in our boats. hell susan has 200 pounds of canned food on the boat at all times JUST IN CASE!! in case of what is beyond me. add tools and extra parts then all my fishing gear plus cloths for a week.... it never ends. twice a summer I take half of it out of the boat but it always finds its way back in.
Les Lampman
New member
Hi Joe and all,
Right you are! All the numbers are seemingly bogus; even the much smaller and lighter CD22 won't hit these figures. To expect 100 horspower to push a 23-foot hull at 34 miles an hour (if it isn't a an exotic material performance hull) is more than optimistic.
It takes about 1 horsepower for every 27 pounds to achieve 34 mph (29 knots) with this type of hull. With 60 gallons of fuel, 700 pounds of additional weight, twin 50 Honda engines and their rigging the boat should have been in the 4500-pound range. It would take approximately 166 horsepower to hit 30 knots. This appears to be correct as that happens to be just about what we get with the Arima 22 Sea Legend (about the same size and weight as the V23) powered with a BF150 (which actually makes 160 hp at 6000 rpm so this works out to 28 pounds per horsepower). The best wide open throttle speed I would hope for with 100-hp on the transom is around 24 knots...about 27.5 miles per hour.
If you choose a 20 knot cruise you need around 70 horsepower for this style hull at 4500 pounds (and I believe this is a low weight for a cruise-ready boat with crew aboard); given the typical EFI outboard today that's about 7 gallons per hour...just shy of 3 nmpg, which is what I would expect from this hull.
Also, the BF50 consumes about .1 gph at 1500 rpm which means the slow speed numbers listed are more than pesimistic. The chart shows a .85 gph fuel consumption at 1000 rpm; in reality eight BF50's would run on that amount of fuel at that rpm.
Right you are! All the numbers are seemingly bogus; even the much smaller and lighter CD22 won't hit these figures. To expect 100 horspower to push a 23-foot hull at 34 miles an hour (if it isn't a an exotic material performance hull) is more than optimistic.
It takes about 1 horsepower for every 27 pounds to achieve 34 mph (29 knots) with this type of hull. With 60 gallons of fuel, 700 pounds of additional weight, twin 50 Honda engines and their rigging the boat should have been in the 4500-pound range. It would take approximately 166 horsepower to hit 30 knots. This appears to be correct as that happens to be just about what we get with the Arima 22 Sea Legend (about the same size and weight as the V23) powered with a BF150 (which actually makes 160 hp at 6000 rpm so this works out to 28 pounds per horsepower). The best wide open throttle speed I would hope for with 100-hp on the transom is around 24 knots...about 27.5 miles per hour.
If you choose a 20 knot cruise you need around 70 horsepower for this style hull at 4500 pounds (and I believe this is a low weight for a cruise-ready boat with crew aboard); given the typical EFI outboard today that's about 7 gallons per hour...just shy of 3 nmpg, which is what I would expect from this hull.
Also, the BF50 consumes about .1 gph at 1500 rpm which means the slow speed numbers listed are more than pesimistic. The chart shows a .85 gph fuel consumption at 1000 rpm; in reality eight BF50's would run on that amount of fuel at that rpm.
Sea Wolf":1gc1c56y said:
The data on C-dory's site seems to me, is the same data that was in the brochure for the 23 Cape Cruiser Venture. I'll have to find the brochure to be sure, but I noticed that the data was suspect when I read it on the brochure.
After hearing about the "Lawsuit" I kept the brochure on account that even if the boat didn't become a collectors item, maybe the brochure would
If someone has one you can look it up, mine is in my summer house up north.
After hearing about the "Lawsuit" I kept the brochure on account that even if the boat didn't become a collectors item, maybe the brochure would
If someone has one you can look it up, mine is in my summer house up north.
I test drove a CC23 (same boat) powered with a Evinrude ETEC 90.
There was 4 of us and the dealer, probably over 1,000 pounds of passengers and an unknown amount of fuel. Otherwise the boat was empty.
The maximum speed was 28 knots(32MPH) on mostly calm water. [Corrected to read 28MPH = 24Knots.]
The dealer and I agreed that the amount of power was "barely adequate" for the load. They replaced the 90 with a 115 hp ETEC and reported much improved performance(details unknown).
ON EDIT: See Les's discusion below about top speed. I now think the GPS was set at MPH and not knots.
There was 4 of us and the dealer, probably over 1,000 pounds of passengers and an unknown amount of fuel. Otherwise the boat was empty.
The maximum speed was 28 knots(32MPH) on mostly calm water. [Corrected to read 28MPH = 24Knots.]
The dealer and I agreed that the amount of power was "barely adequate" for the load. They replaced the 90 with a 115 hp ETEC and reported much improved performance(details unknown).
ON EDIT: See Les's discusion below about top speed. I now think the GPS was set at MPH and not knots.
Les Lampman
New member
That performance isn't achievable with an E-TEC 90 or a Honda BF90 on a lighter and smaller CD22. [I am NOT questioning what Larry saw; I'm just using this as an example.] Even on a "fast" hull (which I don't believe the V23 is) a boat needs one horsepower for every 42 pounds to achieve 28 knots which means the CC23 should have been at 3800 pounds; subtracting the 1000 pounds of people and the engine (about 350# with oil, prop, and rigging) that means the hull would have been 2450# with no fuel or water (another 534 pounds) and that's a lot lighter than they list it at (2950 pounds; subtracting fuel and water would put in at 2416 pounds). Using factory numbers the CC23 should have weighed in at 4500 pounds with 1000 pounds of folks and 30 gallons of fuel. An average hull would require 132 horsepower to achieve 28 knots and a fast hull (performance oriented) would have still required 100 horsepower.Larry H":27ue8i2f said:
It does bring up the fact that getting "hard" numbers is difficult at best without some specific test equipment (a radar gun, a trained operator, and a high precision flow meter). In other words...take all performance claims with a grain of salt unless it's a test conducted under specified conditions with proper test equipment. And then it's only vaild for those conditions...temperature, humidity, altitude, fresh or saltwater, load, prop, boat setup, operator experience, and more.
The main point I'm trying to make is that if you have a known (and approximately honest weight), you know the hull shape and its general attributes, it's dead simple to figure out the horsepower required for any speed. Since modern EFI engines need about .09 to .1 gallons per hour to produce 1 horsepower the fuel burn is also easy to calculate. The factory and others can tell you what ever they want but the truth of the matter is that little has changed in hull design for the typical recreational monohull for many, many years and the numbers used by designers have been thoroughly tested. It's only at peril that a factory or dealer would tout "higher than average" numbers since they're rarely ever achieved.
This also illustrates why I power for cruise speed and not top speed. It takes a lot of horsepower to change the top speed of the boat. For expample, it takes 62 horsepower to move a 4000 pound boat at 20 knots, it takes 100 horspeower to move a 4000 pound boat at 25 knots, and it takes 150 hp to move a 4000 pound boat at 30 knots. So the difference if you want a 25 knot cruise boat or a 20 knot cruise boat in this example is the difference between buying a 100 hp engine or a 150 hp engine...that's about a $4000 decision.
Les,
I am reasonably sure that the five of us on the boat weighed at least 1.000 lbs. Possibly more.
I do remember the maximum speed on the GPS at 28. Perhaps it was 28 MPH which would be 24 knots. This is all from memory so errors are possible.
My CD 22 cruiser when loaded for cruising weighed in at 4500-5000 lbs, possibly more when full of fuel, water, ice and groceries.
When heavy, my top speed using the 70hp two cycle Evinrude was 17-18 knots, by GPS.
Is it possible that the 90hp ETEC actually produced 99-100hp? As I understand the NMMA hp ratings for a motor can be over or under hp by 10% and still carry the rating. Is my understanding of hp rating correct?
I am reasonably sure that the five of us on the boat weighed at least 1.000 lbs. Possibly more.
I do remember the maximum speed on the GPS at 28. Perhaps it was 28 MPH which would be 24 knots. This is all from memory so errors are possible.
My CD 22 cruiser when loaded for cruising weighed in at 4500-5000 lbs, possibly more when full of fuel, water, ice and groceries.
When heavy, my top speed using the 70hp two cycle Evinrude was 17-18 knots, by GPS.
Is it possible that the 90hp ETEC actually produced 99-100hp? As I understand the NMMA hp ratings for a motor can be over or under hp by 10% and still carry the rating. Is my understanding of hp rating correct?
Les Lampman
New member
Hi Larry,
My understanding is the same as yours on rating. There actually seems to be an "under-rating" trend at the moment. That is, some of the engines actually make more horsepower than the model would indicate. I attribute that to getting good reviews in the mags and your engine winning the "shootout" of the 90's or some such. The Honda V-TEC motors are like that; the 150 actually maxes out at 160 and the 90 just under 100. Honda puts the power curves right in their Product Guide (that the dealers get) but not so for the Evinrude engines so it's really anybody's guess what they max out at.
A top speed of 24 knots (~28 mph) would have been very close to the mark with the E-TEC 90 allowing for variables. That also would have been more in keeping with the assessment that the E-TEC was just "adequate". Really, if a boat like the CD22 or the CC23 can hit 28 to 30 knots it typically doesn't feel like the boat is underpowered or only marginally so.
Your reported speed on the CD22 with your 70hp at wide open throttle at the weights you cite would also be dead on with the same formula I'm using for calculating the Venture 23 performance; 18 knots at 4500 pounds requires 69.2 horsepower using that formula.
My understanding is the same as yours on rating. There actually seems to be an "under-rating" trend at the moment. That is, some of the engines actually make more horsepower than the model would indicate. I attribute that to getting good reviews in the mags and your engine winning the "shootout" of the 90's or some such. The Honda V-TEC motors are like that; the 150 actually maxes out at 160 and the 90 just under 100. Honda puts the power curves right in their Product Guide (that the dealers get) but not so for the Evinrude engines so it's really anybody's guess what they max out at.
A top speed of 24 knots (~28 mph) would have been very close to the mark with the E-TEC 90 allowing for variables. That also would have been more in keeping with the assessment that the E-TEC was just "adequate". Really, if a boat like the CD22 or the CC23 can hit 28 to 30 knots it typically doesn't feel like the boat is underpowered or only marginally so.
Your reported speed on the CD22 with your 70hp at wide open throttle at the weights you cite would also be dead on with the same formula I'm using for calculating the Venture 23 performance; 18 knots at 4500 pounds requires 69.2 horsepower using that formula.
Hi all, I've had a 23' Venture (made by CC) for about a year and a half and love it. When I first took it out with full fuel and water, anchor, vests, chairs, and two people it topped out at 34 smph and cruised at 4500 at 23 smph. That is with a Yamaha 90. Now that I have added all that is needed for long range cruising (plates, pots, pans, cups, silverware, microwave, coffeemaker, larger fridge, food, second anchor, flares, extinguisher, BBQ, inverter, battery charger, larger water tank, TV, DVD, antenna, stereo, speakers, trim tabs, fishing gear, fishing rod/speargun rack, etc) I top out at about 31 smph and cruise at 20 smph at 4500 rpm. That is with full fuel, water, 40 pounds of ice in the fish bag, fish gear, dive gear and two people. I average about 3.8-4 smpg. For my local waters a 90 is plenty of power. If you live on the sound with smoother water than I would recommend a larger (115) engine.
Bill
Bill
matt_unique
New member
Very little technical information on the C-Dory website is correct. This is particularly true with the owners manuals in reference to capacities...warranty....etc., etc., etc.
Wow - good discussion. I just thought that their math was wrong... now I see that the data are actually suspect.
So, assuming 4mpg is probably a more realistic (yet still omtimistic) estimate for fuel consumption for a loaded V23, it's 60 gallon fuel capacity would limit round trips to about 80 miles (using the rule of thirds). Dang. I was hoping for more than that, somewhere in the 100-120 mile range without needing to bring extra fuel cans. 5mpg would get me there, 5.5 would be perfect.
So, assuming 4mpg is probably a more realistic (yet still omtimistic) estimate for fuel consumption for a loaded V23, it's 60 gallon fuel capacity would limit round trips to about 80 miles (using the rule of thirds). Dang. I was hoping for more than that, somewhere in the 100-120 mile range without needing to bring extra fuel cans. 5mpg would get me there, 5.5 would be perfect.
AK,
The rule of thirds is 1/3 going out, 1/3 coming home, and 1/3 in reserve.
So 4 MPG x 60 Gals is 240 miles total. 1/3 is 80 miles. So 80 miles out and 80 miles back, and 80 miles in reserve.
If you go 120 miles one way, you would need 90 gals total to fit the rule. You could install saddle tanks of 15 gals each side.
The rule of thirds is 1/3 going out, 1/3 coming home, and 1/3 in reserve.
So 4 MPG x 60 Gals is 240 miles total. 1/3 is 80 miles. So 80 miles out and 80 miles back, and 80 miles in reserve.
If you go 120 miles one way, you would need 90 gals total to fit the rule. You could install saddle tanks of 15 gals each side.
dogon dory
New member
Sorry, Folks - Post Deleted By Author
This is a very interesting and revealing discussion.
One very definite derivative rule of all the ideas discussed would be to always run your boat as light as possible to maximize performance and minimize fuel consumption. Dusty has said and practiced this for years!
To this end, one should periodically conduct boat content inspections to rid the boat of all unnecessary weight. In this case, Less Is More, at least in terms of fuel efficiency,.
This, however, may be practical more for the day cruiser or fisher than the long range cruiser who has to be prepared for a great number of possibilities and emergencies.
Perhaps, then, for the long range cruiser, the best advice would be to look very carefully at all the items required for the trip planned and to see how those necessary can be minimized in weight.
A few years back, we knew of a fellow with a Classic CD-22 who cruised the Inland Passage in SE Alaska with, among other things, a 120 volt chest freezer powered by a gas generator in the cockpit of his boat. Hopefully he was able to take a lot of food with him and return with a chest of fish fillets, but before doing so, I'd look at the cost versus benefit of such a move.
Lighten that boat up! It'll save you gas and make the boat perform better without all that weight. Or just write "LeadBelly" across the transom and forget it!
Joe. :teeth :thup
One very definite derivative rule of all the ideas discussed would be to always run your boat as light as possible to maximize performance and minimize fuel consumption. Dusty has said and practiced this for years!
To this end, one should periodically conduct boat content inspections to rid the boat of all unnecessary weight. In this case, Less Is More, at least in terms of fuel efficiency,.
This, however, may be practical more for the day cruiser or fisher than the long range cruiser who has to be prepared for a great number of possibilities and emergencies.
Perhaps, then, for the long range cruiser, the best advice would be to look very carefully at all the items required for the trip planned and to see how those necessary can be minimized in weight.
A few years back, we knew of a fellow with a Classic CD-22 who cruised the Inland Passage in SE Alaska with, among other things, a 120 volt chest freezer powered by a gas generator in the cockpit of his boat. Hopefully he was able to take a lot of food with him and return with a chest of fish fillets, but before doing so, I'd look at the cost versus benefit of such a move.
Lighten that boat up! It'll save you gas and make the boat perform better without all that weight. Or just write "LeadBelly" across the transom and forget it!
Joe. :teeth :thup
AK,
Checking where you live, I would guess you are either operating in PWS or going out of Homer towards Kodiak. With those long runs and no gas stations, I agree that you need more fuel. I don't think either the CD22, CD25, Venture 23 or even the Venture 26 are going to have enough stock tankage for your use.
As I see it you can only increase MPG or tankage. Some folks use their kicker to increase MPG, but operate slower. In thinking about the Venture 23, saddle tanks seem like a good solution. Another possibility is a bladder tank in the port lazarette. Other than that, 5 gal gas cans work, but they are a hassle. I carried 25 gals in 5's in the cockpit of my 22 on my Alaska runs. If you have a roof rack, the empty 5's can be stowed up there as you use them.
One last option would be to order a Venture 23 without tanks(if the factory would do that) and have custom tanks made to completely fill the area under the splashwell.
Checking where you live, I would guess you are either operating in PWS or going out of Homer towards Kodiak. With those long runs and no gas stations, I agree that you need more fuel. I don't think either the CD22, CD25, Venture 23 or even the Venture 26 are going to have enough stock tankage for your use.
As I see it you can only increase MPG or tankage. Some folks use their kicker to increase MPG, but operate slower. In thinking about the Venture 23, saddle tanks seem like a good solution. Another possibility is a bladder tank in the port lazarette. Other than that, 5 gal gas cans work, but they are a hassle. I carried 25 gals in 5's in the cockpit of my 22 on my Alaska runs. If you have a roof rack, the empty 5's can be stowed up there as you use them.
One last option would be to order a Venture 23 without tanks(if the factory would do that) and have custom tanks made to completely fill the area under the splashwell.