Suzuki 300hp outboard

[kevinsc]

Hi All
Just need a bit of help working out the range in miles I would get. I have a 200ltr fuel tank and would like to put on a 300hp Suzuki outboard on the back, but would like to roughly know if the fuel tank is big enough for a decent range. The outboard at 4k rev uses 36(according to the internet)LTRs per hour, that means I would get 5,5 hours of driving from 200ltrs tank but not sure how to convert to mile range and not sure if am barking up the wrong tree in working it out.
Cheers Kevin

[willk]

Not an answer, but food for thought:

willk's Law #2

[willk]

Originally Posted by kevinsc

The outboard at 4k rev uses 36(according to the internet)LTRs per hour, that means I would get 5,5 hours of driving from 200ltrs tank but not sure how to convert to mile range and not sure if am barking up the wrong tree in working it out.

You're on track to the answer - the catch is you need to find out how fast your boat will run a 4k rev with a full load. Simples after that. Maybe tell us what boat you have?

My own experience being pushed by two such motors is that holding the reins tight at 4k was a job with a stronger will than mine. Geddup!

I'm kinda presuming that you are sticking this engine on a c.7.5m RIB? If so, it will be awesome but possibly you are a little light on fuel capacity. Yes, it's 5.5 hours but that's really 4 plus reserve. Then, you're not gonna run at 4k or less - life's too short! If you are committed to the 200L tank, fair enough, but plan for storage on deck as well if you intend to cruise.

[kevinsc]

Hi Willk
Yes it is an 7.5m ribtec rib, it came with a 200ltr tank and was going to change it but want £2k for a s/steel 280ltr tank, and I'm struggling to get a plastic tank with the 300mm height I have. I know the rib is heavy but don't know how fast it will go, I did work out 154 mile not sure if that's right. On long cruising I will probably have to have a tank on deck.
Cheers Kevin

[paulbrown22]

With that engine/hull combo I'd suspect 4000RPM is around 30kn give or take a bit, so a likely max of 150NM-ish range if you were draining the entire tank, so realistically 100-120NM safe range with some reserve.

[kevinsc]

Originally Posted by paulbrown22

With that engine/hull combo I'd suspect 4000RPM is around 30kn give or take a bit, so a likely max of 150NM-ish range if you were draining the entire tank, so realistically 100-120NM safe range with some reserve.

Hi Paul
I got the roughly the same, but I thought I would get more and was working it out wrong. But sadly not I think I will have to install a second tank to give me about 200 miles safety.
Cheers Kevin

[diver 1]

I'd like to leave a reserve of 25L or so in any planning calculations.

Modern petrol isn't very stable and doesn't last long due to ethanol content which is becoming almost unavoidable now

I am re-building my rib, I've gone for a smaller inboard tank (180L) which will be the norm and ensure a healthy turnover of fuel.

For longer trips I have a 60L plastic tank that can be strapped down on the deck for extra range. In the past I've even carried a couple of 25L drums of fuel as extra supplement for longer voyages.

Installing an under deck tank properly is not a simple undertaking.

[kevinsc]

Originally Posted by diver 1

I'd like to leave a reserve of 25L or so in any planning calculations.

Modern petrol isn't very stable and doesn't last long due to ethanol content which is becoming almost unavoidable now

I am re-building my rib, I've gone for a smaller inboard tank (180L) which will be the norm and ensure a healthy turnover of fuel.

For longer trips I have a 60L plastic tank that can be strapped down on the deck for extra range. In the past I've even carried a couple of 25L drums of fuel as extra supplement for longer voyages.

Installing an under deck tank properly is not a simple undertaking.

Hi diver
Your right about unleaded not lasting as long anymore. At the moment I've got the deck off the rib so it would easier to install another tank but still will have to strap fuel tanks on deck for weekend cruises.
Cheers Kevin