Another fuel consumption question

[smokie]

Does the design of a hull make a big difference in fuel consumption on a rib?

One rib manufacturer states that their 7m rib will consume 7.5 litre per hour at 30 knots (lightly loaded) with a Merc 1.7L DTI Turbo Diesel.

Can I expect anything close to that with a 7m rib from another manufacturer configured similar and the same engine?

[tsunami]

Hi Smokie,
Every hull will have different characteristics and will therefore have different resistance factors that will effect fuel consumption and speed.
Also the weight of a rib will have a large effect on the fuel consumption, the weight of a 7m rib can vary quite a lot depending on the manufacturer with the boats designed more for heavy weather and commercial use normally being significantly heavier than the standard leisure ribs.
An easier way to look at it would be the max speed of 2 different 7m ribs. If one boat was capable of 40knots with a 150hp fitted and the other capable of 35knots with the same engine then the slower rib is most likely heavier on fuel as the boat is harder to push!