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Thread: Power Cat 18MPG Interesting?

  1. #1

    Default Power Cat 18MPG Interesting?

    As I was reading the latest posts regarding Power Cats, I thought you guys maybe interested in some of the specs and features of this "Concept" power cat.
    LOA 36 feet, BOA 14 feet, Draft 14 inches
    Cruising Speed 18-20 Kn, MPG 18.1
    Granted this is a tease there are more exciting features and specs to publish and of course open water tests by January-March 2014.
    Let me know what you all think.

  2. #2

    Default Re: Power Cat 18MPG Interesting?

    Quote Originally Posted by victor View Post
    As I was reading the latest posts regarding Power Cats, I thought you guys maybe interested in some of the specs and features of this "Concept" power cat.
    LOA 36 feet, BOA 14 feet, Draft 14 inches
    Cruising Speed 18-20 Kn, MPG 18.1
    Granted this is a tease there are more exciting features and specs to publish and of course open water tests by January-March 2014.
    Let me know what you all think.
    I am sure we all would, but where, who, what? More info required

  3. #3

    Default Re: Power Cat 18MPG Interesting?

    My pickup truck doesn't get 18 mpg.
    Not buyin it. No way.

  4. #4

    Default Re: Power Cat 18MPG Interesting?

    Quote Originally Posted by Sand crab View Post
    My pickup truck doesn't get 18 mpg.
    Not buyin it. No way.
    Maybe if you had wave piercing hulls and drew14 inches and weighed a lot less then you do; you might.

  5. #5
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    Default Re: Power Cat 18MPG Interesting?

    1gph fuel burn at 18mph? DamnThat might make me switch....

  6. #6

    Default Re: Power Cat 18MPG Interesting?

    Quote Originally Posted by Sand crab View Post
    My pickup truck doesn't get 18 mpg.
    Not buyin it. No way.
    Sand Crap not meaning to be flip; progress happens even in boating think cats doing 50 plus mph. We'll to be completely honest on paper we can do 18mph at 18 kns still needs to be proven with up coming sea trials.

  7. #7

    Default Re: Power Cat 18MPG Interesting?

    Quote Originally Posted by Peter View Post
    I am sure we all would, but where, who, what? More info required
    Peter sea trials schedule for Jan/ March 2014
    More details to follow
    Just think weight to HP Ratio

  8. #8

    Default Re: Power Cat 18MPG Interesting?

    Quote Originally Posted by Sand crab View Post
    My pickup truck doesn't get 18 mpg.
    Not buyin it. No way.
    Sorry I MENT NOW DISRESPECT SAND CRAB

  9. #9

    Default Re: Power Cat 18MPG Interesting?

    That's OK. I just need more info.

  10. #10

    Default Re: Power Cat 18MPG Interesting?

    Quote Originally Posted by Sand crab View Post
    That's OK. I just need more info.
    So am I missing something is there a link to this mythical cat

  11. #11
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    Default Re: Power Cat 18MPG Interesting?

    Quote Originally Posted by victor View Post
    Cruising Speed 18-20 Kn, MPG 18.1

    Let me know what you all think.
    18-20 cruise implies 22-25 knots maximum speed or the engines won't last long

    Irrespective of the boat (or car, lawnmower) a typical engine uses about 3/4gal an hour for every 10hp. So to use just 1 gal an hour (18 knots at 18mpg) means the maximum engine hp cannot be more than 15hp

    So it's got to be a very, very light cat to go that fast (and then only in flat water no wind conditions)

    However 14in draft implies 24-30in WL beam for maximum efficiency. Or 350 x 700mm x 10m length (say) implies about a 2.5T total displacement minimum. So hardly light

    So please tell us more - is it a foiler?

    Richard Woods of Woods Designs

    www.sailingcatamarans.com

  12. #12
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    Canada
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    246

    Default Re: Power Cat 18MPG Interesting?

    Thanks for the math Richard.
    It's posts like yours that separate the wheat from the chaff. And there's a lot of chaff on Sailing forums.

    Paul.

  13. #13

    Default Re: Power Cat 18MPG Interesting?

    Quote Originally Posted by Woods Designs View Post
    18-20 cruise implies 22-25 knots maximum speed or the engines won't last long

    Irrespective of the boat (or car, lawnmower) a typical engine uses about 3/4gal an hour for every 10hp. So to use just 1 gal an hour (18 knots at 18mpg) means the maximum engine hp cannot be more than 15hp

    So it's got to be a very, very light cat to go that fast (and then only in flat water no wind conditions)

    However 14in draft implies 24-30in WL beam for maximum efficiency. Or 350 x 700mm x 10m length (say) implies about a 2.5T total displacement minimum. So hardly light

    So please tell us more - is it a foiler?

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
    Richard thanks for your input; power cat 36 ft weighing 4500lbs, twin 38hp diesels.
    Weight to HP ratio is what's going to give 18 mpg coupled with the proper prop pitch. Top speed will be 22.9. Also wave piercing hulls will give good performance in most any conditions.
    Within the next month we will have test results ready.
    This is not the first hull of this design, we ran a 33 foot model which provided real world test results. This is a stretched version repowered with diesels.

  14. #14

    Default Re: Power Cat 18MPG Interesting?

    Quote Originally Posted by Woods Designs View Post
    18-20 cruise implies 22-25 knots maximum speed or the engines won't last long

    Irrespective of the boat (or car, lawnmower) a typical engine uses about 3/4gal an hour for every 10hp. So to use just 1 gal an hour (18 knots at 18mpg) means the maximum engine hp cannot be more than 15hp

    So it's got to be a very, very light cat to go that fast (and then only in flat water no wind conditions)

    However 14in draft implies 24-30in WL beam for maximum efficiency. Or 350 x 700mm x 10m length (say) implies about a 2.5T total displacement minimum. So hardly light

    So please tell us more - is it a foiler?

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
    No it's not a foiler.
    Richard I see and understand your numbers however my 11,000 SeaWind burns 3/4 gallons per hour at 6 plus kn burning gas. It's conceivable that a 4500 lb wave piercing hull using diesel can triple the speed of a 11000 lb SeaWind, the tests will prove it I hope.

  15. #15

    Default Re: Power Cat 18MPG Interesting?

    Quote Originally Posted by Woods Designs View Post
    18-20 cruise implies 22-25 knots maximum speed or the engines won't last long

    Irrespective of the boat (or car, lawnmower) a typical engine uses about 3/4gal an hour for every 10hp. So to use just 1 gal an hour (18 knots at 18mpg) means the maximum engine hp cannot be more than 15hp

    So it's got to be a very, very light cat to go that fast (and then only in flat water no wind conditions)

    However 14in draft implies 24-30in WL beam for maximum efficiency. Or 350 x 700mm x 10m length (say) implies about a 2.5T total displacement minimum. So hardly light

    So please tell us more - is it a foiler?

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
    Richard thanks for your input; power cat 36 ft weighing 4500lbs, twin 38hp diesels.
    Weight to HP ratio is what's going to give 18 mpg coupled with the proper prop pitch. Top speed will be 22.9. Also wave piercing hulls will give good performance in most any conditions.
    Within the next month we will have test results ready.
    This is not the first hull of this design, we ran a 33 foot model which provided real world test results. This is a stretched version repowered with diesels.

  16. #16
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    Default Re: Power Cat 18MPG Interesting?

    Interesting:

    Maybe others with 27-45hp diesels can comment on whether they use less than 1/2 gal hr at cruising revs. I know the Kubota diesels on the boat I was sailing for the last few weeks are not that economic

    What will be your range under power? I assume you will carry at least 50gal fuel - which implies a 1000 mile range - so it would be easy to make it a true ocean crosser

    Richard Woods

  17. #17

    Default Re: Power Cat 18MPG Interesting?

    Quote Originally Posted by Woods Designs View Post
    Interesting:

    Maybe others with 27-45hp diesels can comment on whether they use less than 1/2 gal hr at cruising revs. I know the Kubota diesels on the boat I was sailing for the last few weeks are not that economic

    What will be your range under power? I assume you will carry at least 50gal fuel - which implies a 1000 mile range - so it would be easy to make it a true ocean crosser

    Richard Woods
    Richard those others are not weighing in at 4500lbs

  18. #18
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    Default Re: Power Cat 18MPG Interesting?

    Sorry, I'm still confused. Surely a boat's displacement has nothing to do with fuel consumption per hour? But engine size and horsepower does.

    Does your Seawind use twin 35-40hp outboards (obviously they are not diesels as you say you use gas)? If it does then 6 knots cruising speed is seriously slow - even if the fuel consumption for twin 35's is amazing. I've never done better than 10mpg with a 9.9hp on a 35ft cat

    Having said that, I hope your tests prove me wrong because "better than car mileage" for a powerboat will certainly put the cat amongst the pigeons, so to speak

    Richard Woods

  19. #19

    Default Re: Power Cat 18MPG Interesting?

    Quote Originally Posted by Woods Designs View Post
    Interesting:

    Maybe others with 27-45hp diesels can comment on whether they use less than 1/2 gal hr at cruising revs. I know the Kubota diesels on the boat I was sailing for the last few weeks are not that economic

    What will be your range under power? I assume you will carry at least 50gal fuel - which implies a 1000 mile range - so it would be easy to make it a true ocean crosser

    Richard Woods
    A single 30hp Lombardini drinks between 1.86 & 1.93 I/hr @ 2400 rpm and 2.16 & 2.21 l/hr @ 2600 rpm (0.492 USG/hr and 0.585 USG/hr) assuming my rev counters and fuel measurements are reasonably accurate.

  20. #20

    Default Re: Power Cat 18MPG Interesting?

    Quote Originally Posted by Woods Designs View Post
    Sorry, I'm still confused. Surely a boat's displacement has nothing to do with fuel consumption per hour? But engine size and horsepower does.

    Does your Seawind use twin 35-40hp outboards (obviously they are not diesels as you say you use gas)? If it does then 6 knots cruising speed is seriously slow - even if the fuel consumption for twin 35's is amazing. I've never done better than 10mpg with a 9.9hp on a 35ft cat

    Having said that, I hope your tests prove me wrong because "better than car mileage" for a powerboat will certainly put the cat amongst the pigeons, so to speak

    Richard Woods
    Hi again Richard. Let me clear up the performance of my SeaWind under power. Under power I'm turning 3800 RPM doing 7 kn burning 1.1 GPH. Two 9.9 yamaha.
    I'm sorry but I don't understand when you say weight has nothing to do with fuel consumption. Please Follow my logic here, a vessel weighing 10000 lbs will do speed x a vessel weighing 20000lbs to go the same speed x will need more HP and more HP generally needs more fuel. Now if you have a 36 foot vessel that weighs say 4500lbs with two 38hp diesel cruising at 18 kn it's possible to get better fuel consumption than a 37.6 foot power cat weighing18900 lbs with 600 hp, which by the way gets1.2 MPG. Check Glacier Bay.
    Yes we also hope we will prove that the power marine industry has had it wrong by consistently perducing boats that are over weight and instead of using modern building materials to lessen weight they just keep increasing the HP. Reminds me of the American car industry and we know what happened to them.
    Richard thanks again for your input.

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