how fast is your rib?

[r4e]

Originally Posted by jyasaki

Out of curiosity, what's your fuel consumption at that speed?

Fuel consumption at max revs is about 1.2 liters per nautical mile per outboard, i.e. total 2.4 liters per nautical mile or about 120 liters/h or 2 liters per minute. Or 31.7 gallons per hour. The tanks can hold four hours of gas at max speed.

However, if you compare this to the minimum consumption soon after planing speed, about 0.95 liters per nm per outboard, the difference is not so big that I would select the speed by economy only.

It makes it easier for me to justify all the maintenance costs if I manage to spend more on gas (=enjoying the boat) than on maintenance. I've had one transmission replaced completely, all the hypalon pontoons replaced (custom made) and the electrical systems rewired. Plus added side scan sonar and other goodies. That's a lot of gas to burn yet;-)

[jyasaki]

Originally Posted by r4e

Fuel consumption at max revs is about 1.2 liters per nautical mile per outboard, i.e. total 2.4 liters per nautical mile or about 120 liters/h or 2 liters per minute. Or 31.7 gallons per hour. The tanks can hold four hours of gas at max speed.

Thanks. Just curiosity driving that question.

jky

[khalidow]

thaks to all the help regards to my post plane off problems, i officially lowered outboard made some spacers so motor has more tilting angle. i officially get about 57mph with 4 crew onboard vessel with my 5m duck and mercury 225hp no chine walking nothing, drives like a dream. rev gauge doesn't work some wiring issue but will keep u posted

not that i need to go any faster is that weak for a 1980's 225hp
or am i suppose to get more power from it?

[Hysucat]

Mmmm .... is that all, I was just getting into it.

This was a standard boat and engines, the only modifications were the gearboxes and props.

8m Hysucat - 2x 200 Mercury's (Standard), bullet nose racing gearboxes, low level water pickups, surface piercing props.

74knots / 85mph / 137kmph on final day of testing. Pretty sure it can make 80knots with jack plates on the transom.

Hysucat 8m adrenalin waverunner in Struisbaai - YouTube

Hysucraft - Evolution Evolved. - Official Website - Designers & Developers of Hydrofoil Assisted Craft.8m RIB

I guess Cooke still beats me with his Malcolm Cambell setup

[Cookee]

We weren't using a surface piercing prop at all - in fact the record run was with a modified Raker. The best set up we had which was on Coniston was a Mercury 280EFI ROS 15" with a modified Sportmaster. If you need a bit of bow lift use a Raker, a surface piercing prop will lift the stern if anything.

[Hysucat]

Originally Posted by Cookee

We weren't using a surface piercing prop at all - in fact the record run was with a modified Raker. The best set up we had which was on Coniston was a Mercury 280EFI ROS 15" with a modified Sportmaster. If you need a bit of bow lift use a Raker, a surface piercing prop will lift the stern if anything.

Hi Cookee, the front and rear hydrofoils do the job of getting the boat out the water. With my ideal setup the idea we have to get as much of the boat and engine out the water. This boat hit the wall at 5000rpm, nowhere near the 6200 limit. Getting the engine further out the water will have it kicking up a nice rooster tail and manage to get full revs.

[HCD Canada]

50.8 MPH on a Aquarius aqua cat 18 pitch cleaver

[Cookee]

Originally Posted by Hysucat

Hi Cookee, the front and rear hydrofoils do the job of getting the boat out the water. With my ideal setup the idea we have to get as much of the boat and engine out the water. This boat hit the wall at 5000rpm, nowhere near the 6200 limit. Getting the engine further out the water will have it kicking up a nice rooster tail and manage to get full revs.

You just need a smaller pitch prop - smaller diameter can have the effect of increasing revs and speed but it depends on how high you're running the prop and other factors.

[blueboy758]

Compared to some speeds here I think my boat and engine are broke.... 5.3 offshore fairly wide 115 ficht about 40 on a good day three up and 50 ltrs of juice.

[AK2AZ]

5.3m Zodiac Pro Hurricane
60 gallons of fuel
115 2-stroke Mercury
4-blade prop
500# misc. gear w/2persons
40mph @ 5,250rpm burn rate 5/gal. hr
...not propped for speed as it chine-walks over 43mph.