Evinrude eTEC 90 hp on Ballistic 5.5 MPG

[Jeremy]

Having just gone mad and bought my first RIB I was more than a little shocked to hear that I might get roughly 1 mile (nautical or otherwse) per litre out of it! It has a 90 litre tank and I was thinking I might try Cherbourg (from the Solent) which I reckon to be 60 ish miles as the seagull flies for lunch one calm day! Am I going to need the RNLI and appear on the news or do I just go by myself with fuel tanks everywhere?
From some of the threads on the same subject it seems I need higher level maths and a ready mileage/ US gallons converter and a small computer. All I really need to know is whether I could make the trip at something less than full speed and the family on board!!

[Nos4r2]

Is it your 1st boat or 1st rib? If it's your 1st boat, get some training before trying a long hike like that. PB2 as a minimum.

As for fuel consumption, take it out with a full tank in conditions varying from calm to rough and check your GPS distance travelled. Then refill the boat and work it out.

[Polwart]

Originally Posted by Jeremy

Having just gone mad and bought my first RIB I was more than a little shocked to hear that I might get roughly 1 mile (nautical or otherwse) per litre out of it! It has a 90 litre tank and I was thinking I might try Cherbourg (from the Solent) which I reckon to be 60 ish miles as the seagull flies for lunch one calm day! Am I going to need the RNLI and appear on the news or do I just go by myself with fuel tanks everywhere?
From some of the threads on the same subject it seems I need higher level maths and a ready mileage/ US gallons converter and a small computer. All I really need to know is whether I could make the trip at something less than full speed and the family on board!!

Is this your first boat? How much experience do you have? The question suggests you may not have undertaken any training (it was certainly covered in my PB2 course) ... in which case a cross channel trip is certainly ambitious.

[Edit - sorry Nos - already said this whilst my fingers were transferring thoughts to the screen.]

90 HP will use roughly 34 litres per hour at full throttle. So you have about 3 hours "endurance" at full power. You will probably get over 4hrs at optimum cruising speed. I think this is probably enough for a cross channel trip, but not a lot of scope for cock ups and almost certainly not enough for a round trip. If it was me I would take a spare 25-30L along in a portable tank and refil in france.

Normal recommendation seems to be to carry at least 20% spare in reserve.

[Jeremy]

Dear Nosfurato, thanks for your thoughts.. it's our first RIB but have RYA Coastal Skipper amongst other bits of paper so I should be able to find Cherbourg and I'll have a PB 2 as crew. I'll be doing the old "top it up and run it" trick for sure but was hoping for some better news on the "estimate" of one mile per litre.

[Chris]

Originally Posted by Jeremy

Dear Nosfurato, thanks for your thoughts.. it's our first RIB but have RYA Coastal Skipper amongst other bits of paper so I should be able to find Cherbourg and I'll have a PB 2 as crew. I'll be doing the old "top it up and run it" trick for sure but was hoping for some better news on the "estimate" of one mile per litre.

On my Etec I find I get about .8 litres per NM at about 25 knots.

I would expect you will see similar but certainly not much less.

[Jeremy]

Dear "Nos" and Polwart,

Thanks again to you both. I was certainly expecting to have to refuel "en France" and will take 20 litres in cans so here's hoping for a fair passage some time soon. I'm guessing here but I take optimum cruising speed to be 75% of max revs or just up on the plane!
Over

[Jeremy]

Dear Chris,
With my O level maths, your numbers and the 3-4 hours "endurance" at optimum speeds from Polwart I believe I have a range of no more than 100 nm! Should see me there OK...
Out - with many thanks for your help.

[codprawn]

Just go for it.

The very first trip I did on my RIB was from Guernsey back to Weymouth - about 90 miles not counting me getting lost a few times until I had sussed the Raymarine - the route I thought I was following turned out to be an undersea cable - luckily it seemed to be going the same way!!!

I have also crossed the Bristol Channel from Swansea to Ilfracombe and back in my quicksilver 3.1m with a Suzuki 15hp - that's 26 miles each way...........

[Nos4r2]

Originally Posted by Jeremy

Dear Chris,
With my O level maths, your numbers and the 3-4 hours "endurance" at optimum speeds from Polwart I believe I have a range of no more than 100 nm! Should see me there OK...
Out - with many thanks for your help.

Take twice the fuel you think you'll need. Your 1mile/litre will double if you have to work the throttle a lot. I've used 30 litres before just going Yarmouth-Portsmouth in bad weather.

[Polwart]

Originally Posted by codprawn

The very first trip I did on my RIB was from Guernsey back to Weymouth - about 90 miles not counting me getting lost a few times until I had sussed the Raymarine - the route I thought I was following turned out to be an undersea cable - luckily it seemed to be going the same way!!!

Cod - given that your relationship with your builder didn't seem to be particularly good, and there were details you weren't happy with - was it wise to make the first trip long distance through busy shipping channels? I'm not sure that I would advocate "luck" for getting safely across from the CIs nor getting the navigation right.