Fantasy Rib time!

[Simon B]

OK Chaps, what's the best diesel engine to buy to couple up to a hamilton waterjet in my fantasy 6.8-7.8 build?

Cummins mentioned by Andre looks good.

[MarkWildey]

SeaTek bi-turbo or maybe a FPT

[RIBRyda]

Not getting into specific makes, models or types - just bear in mind that even as a dream boat you'd need to allow at least 50% more power for a jet unit than for a comparable conventional prop unit; last time we did the sums we decided to bin the idea quickly on cost and economy grounds. IMHO of course!

[GJ0KYZ]

That's an interesting question; I think my next boat will have a jet drive since I'm only really interested in skinny water cruising nowadays. Ribcraft recommend a Hamilton HJ322 water jet drive, ZF Marine 280 1:1 direct mounted marine transmission, Centa GZ double element coupling drive shaft and Caterpillar 3126 7.2 litre diesel for their 10.5m boat (£98K all in). I don't know what they'd suggest for a smaller rib.

Thing is, if you only want a jet drive for shallow water it may pay to look at craft other than ribs. For instance SeaDoo have a 23' runabout aimed at the US market but which is available through UK dealers. It looks ghey and you probably have to be a trustafarian to own one but it's powered by two 215hp Rotax 4-stroke supercharged direct drive jets resulting in 55kts WOT and - check this - a draft of only 12 inches! I could get to M.St.M on neaps with that kind of baby. Lush.

http://www.sea-doo.com/en/sportboat/...challenger230/

[willk]

Originally Posted by GJ0KYZ

check this - a draft of only 12 inches! I could get to M.St.M on neaps with that kind of baby.

Yes, but ze inhabitants, zay vood fart in your general directionne and suggest that your fazzer smelled of elderberries.

"Ghey" - I am amused

[Mollers]

Jet drive- The best way to turn horsepower into bubbles without all that unecessary propulsion.

[GJ0KYZ]

Originally Posted by Mollers

Jet drive- The best way to turn horsepower into bubbles without all that unecessary propulsion.

err... have you seen the accelaration figures for jetskis like the SeaDoo RPX-X? 0-50mph in under three seconds. Check this out:

http://www.youtube.com/watch?v=_bZ6H08-tpY

[GJ0KYZ]

Originally Posted by willk

Yes, but ze inhabitants, zay vood fart in your general directionne and suggest that your fazzer smelled of elderberries.

That's a bit of a negative attitude you have toward the French there Willk. The French ribbers who visit this site have probably have never heard of MPFC. Personally I've always found the French to be extremely courteous sailors.

[willk]

Originally Posted by GJ0KYZ

That's a bit of a negative attitude you have toward the French there Willk.

Not at all, but as a Foreigner on this site, I say the French are well able to look after themselves and we must all paddle/pole* our own rib, draft permitting.

I've always found the French to be dead on (I employ 3), once they knew that I wasn't English...

_____________
*Poles are another matter

[Simon B]

Originally Posted by RIBRyda

Not getting into specific makes, models or types - just bear in mind that even as a dream boat you'd need to allow at least 50% more power for a jet unit than for a comparable conventional prop unit; last time we did the sums we decided to bin the idea quickly on cost and economy grounds. IMHO of course!

Strewth, I thought it was 33% that Cameron has much to answer for in terms of inflation!

The jet idea was to reduce possibility of prop strike on divers in water. Not to bothered about acceleration but economy could be a factor.

Keep the ideas coming, it's the only way I'll learn!