Which motor for a 5.4 RIB

[rdewaard]

I want to buy a outboard motor in the next months for a 5.4 mtr RIB (Prestige trimaran). What motor do I need, taken into account:
- usage = diving
- load = 4 - 6 divers
- speed = enough for Northsea to reach remote wrecks, say 20 miles offshore
- fuel economy because of limited tank and expenses ofcourse.
- reliable (due to single engine space only)
- occasion prefable due to price range
(<= 5000 pound)
TIA

[Powerboat]

Hi ,

have a look at the Yamaha 80 hp 4 stroke .

Normally 50 to 60 hp would be enough for a 5 meter RIB but given that you will be carrying divers you will need that extra bit of power to get on the plane .

This engine will give you reliability , power , range and economy . I'm not sure if it will come in at under stg£5,000 .

Our own training boat Ally Cat which can be seen on our website www.powerboat.org is a 6.8 M Lencraft Lynx ( Mil Spec hull ) She is powered by a 100 hp Yamaha 4 stroke and uses only about stg£6 per day in fuel during a one day Powerboat Coxswains course . Her top end speed is 35 knots .( petrol is about stg£0.55 per litre here in Ireland .

Best wishes ,

Stuart www.powerboat.org
Stuart McNamara
National Motor Boat and Power Boat Trainer
ISA / IWAI

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www.powerboat.org

[Alan Mckewan]

If your price range is restricted I would suggest the Suzuki 90 (or 100) two stroke. We have a 90 new last year on a 5.6 Osprey used by the club diving section. It replaced a similar previous 8 year old 100 which gave good service until it threw a leg (since repaired). I think the 100 is now discontinued but the 90 is definitely available at a very competitive price (<4K?). Excellent low rev pulling power, easily copes with 5-6 divers plus gear, consumption not up to 4 stroke standard at lower revs but quite acceptable when run at close to full throttle. My buddy Hugh also has a 100 (same engine with very minor carb differences) new last year on a Humber 5.5 which does around 40 with two up at about 30 litres per hour. This is a well proven V4, relatively light, very smooth but a wee bit noisy.
I would also suggest a look at the new Suzuki 90 /115 4 stroke but it will certainly be above your 5k limit!