gas milage and speed

Laken

Recruit
Joined
Jul 30, 2005
Messages
4
Hey I was just trying to find out about how fast a johnson 115 on a 25 foot pontoon should go, and what kind of gas milage it should get. I just purchased this one and it is running about 18 and getting about 2 miles to the gallon. Just wondering if that was normal..??? Thanks
 

CFronzek

Petty Officer 2nd Class
Joined
Aug 11, 2002
Messages
118
Re: gas milage and speed

This post looks familiar. Didn't you post this previously? I may be mistaken so here's the answer again. <br />Pontoon boats don't plane. They have displacement hulls. Every displacement hull has a characteristic hull speed based on waterline length. The boat will easily get up to hull speed (a 25ft displacement hull has a h.s. of about 7-10 mph) but, beyond that every 1 mph increase takes twice as much horsepower as the previous 1 mph. <br />When you apply a lot of HP to a displacement hull it tries to plane but never will. It is trying to climb a hill of water but never gets on top. <br />If you keep your boat off that hill you can probably drive it at hull speed with 40 HP and at modest RPM's that will get you great gas mileage to boot.<br />Charlie
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: gas milage and speed

Non-repair topic
 
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