New Engine thoughts!

[Alan]

OK, so the Johnson 150VRO on our BWM DS 21 expired in an expensive death rattle on Good Friday. (Why do these things always happen at the begginning of the season?!) To use the technical term its "Beyond Economical Repair" so we need a new engine to fit to our 98 model RIB.

Fuel economy is a priority but we don't want to spend a fortune on a new engine. That rules out a Yamaha HPDI!

My question to the assembled experts out there in Cyberland is:

For a 6.5M RIB, used mainly for cruising, fishing and a little watersports what size and type of engine would you recommend and why?!

The boat has 6 jockey seats, a big console and 40 gall underdeck tank and is fairly heftily laid up so its no lightweight speed machine.

Obvious thoughts would be a 150 Ficht or Optimax, but what about a 135? 4 strokes appeal but the Honda 130 weighs loads (300+ kg if my memory serves) which is a lot of weight. Anybody with experience of this engine on a 6.5m RIB? The Yamaha 115 4stroke is a cracking little engine but would it be big enough to give us a sustained 30kt cruise and drag a lardy skier out of the water?!

Any hot tips on the best dealers for new engines? (The ones with the keenest prices but who know what they are talking about when it comes to rigging the engine!)

Or does anyone out there have a decent used 135/150hp O/B for a good price?!

All advice, abuse, an amusing contributions gratefully received!

Cheers,
Alan

[Powerboat]

I know several of our clients have had Honda 4 stroke 130s fitted to Lencraft Ribs in the 6.5 to 7.5 recently and seem to be fairly happy . I'll make a few calls tomorrow for you and get more accurate info .

300kg sounds very heavy given that the Yammy 115 4 stroke is only around 170kg

Two of my Army Boat Squad RIBs are Lencraft Lynx 6.8 m boats fitted with Yammaha 115 2 strokes and both pull 35 knots with a fully armed 4 divers and Cox aboard

I hear whispers that Yamaha and Suzuki are close to realeasing 200 hp 4 strokes this season .

On the subject of where to buy your engine , my advice is always if possible to buy it and have it hung by the guys who built your boat .

Best wishes ,

Stuart www.powerboat.org

------------------
www.powerboat.org

[John Kennett]

Stuart
I'm really surprised to hear that you get that sort of speed out of a boat that size with 5 up, from just a 115hp engine!


Alan

I would normally reckon on a 150 as being the right size for this boat. You certainly don't need to go any bigger, but from Stuart's experience you might get away with smaller.

It might be worth trying Jonny Boys to see what he's got second hand www.ribsforsale.com

Someone else worth talking to is Lee Fairweather in Fareham www.ribsdirect.com who knows a thing or two about rigging engines on RIBs.

Good luck!
John

[Rannsachair]

I currently run a Redbay 6.1 with a Yamaha F115 4-stroke. This a relatively heavy boat with full width console,6 jockey seats and inboard fuel tank. With 4 adults it will run at over 35 knots and two up 38 knots.

At cruising speeds I average ~3.5 GPM: which together with the low noise and weight reduction over the Honda made this the ideal engine for me.

Not sure about water ski-ing though! If you are acustomed to 150hp on this boat you may feel a 115 is too slow.

Good Luck

[Scubakid]

I have a 6.55 Ribtec with a 130 Honda and performance is good 35+ knots this is with 300 liters of fuel and 3 people aboard

[Alan]

Thank you one and all for your advice and thoughts.

We've gone for a Merc 150 Optimax as the best option at the best price. Should hopefully be rigged by the end of the month.

Now all we need is for the weather to improve....

Alan

[Alan]

Collected boat with Shiny new 150 Opti and smart gauges yesterday. Certainly looks good.
Sea trials this weekend down at Plymouth for the BIBOA SW Cruise. Can't wait!

Let you know how we get on.

Alan