Advice needed on a new RIB for tourism in Brazil

[Robbie D]

I would like to begin by saying how much I enjoy your forum. Wisdom combined with wit make for an enjoyable learning experience. I am starting an ecotourism business just outside of Rio de Janeiro and would greatly appreciate any help or advice offered. I am more or less forced to go with a Brazilian manufacturer of RIBs because of lack of vendor support for imports. They seem to make a decent quality boat on the surface (no pun intended), and they offer a seating configuration unlike any I've seen from another maker. If anyone is interested in offering some feedback, they have an English version website since they're starting to export to the U.S. The model I am most interested in is the SR-760, 22 person diesel sterndrive version, unless someone has a compelling arguement to go with petrol sterndrive or twin OB's (not intended to start another forum sh**storm).

Their main site is:
www.flexboat.com.br

and the page that links page to all the versions is:
http://www.americanflexboat.com/prod...r760models.htm

They will put in a Volvo or a Yanmar, but service here is better and more widespread for Mercury. If I can sell enough blood, I'd probably opt for the cummins mercruiser 4.2L D-Tronic 250hp (225@prop) with a Bravo 3 leg, and possibly an auxilliary outboard (will always be close to shore with other boats nearby). Since I'll be hauling around an average of 3000 lbs. worth of tourists 3 or 4 times a day, my main concerns are low-end torque for faster planing under load and fuel economy. Average cruising speed will be about 28 mph with not much need for higher speeds or WOT (unless I'm trying to impress a string-bikini-wearing Brazilian nubile). Also, diesel prices are roughly 65% of petrol prices, and petrol quality can be circumspect down here.
The price of this configuration, fully rigged without the motor, is 31,000 USD. The list price for the 4.2 D-Tronic here is 36,000 USD, so I'll be trying to import a new one or find a good quality used unit. They'll install any motor I send to them with no additional labor charges.

The basic route will include calm water, open ocean, maneuvering through sea caves and rock formations, and whale/dolphin/turtle watching, depending on the season. And a few beach stops for swimming.

Any comments or suggestions, negative or positive, will be greatly appreciated. I hope to be a regular in these forums and one day hope to understand half as much as most of you know about Ribbing.

Thanks in advance, RD

Free rides for any and all who can make it down here!

[Brian]

Robbie
Welcome to the forum.
I am sure that others more competant than I will comment, but at first sight my thoughts are:
Not enough Horse-Power. 250hp is not enough to push 3000lbs of people, plus boat (?a further 6000lbs? All those seats!)
?Will engine of that size take the duty load anyway?
Quite agree with you on diesel.
?Will the weight/duty load, blow the Bravo 3 leg? I will say YES !! to that one. Bravo 2 yes, even Bravo 1, but not 3.
I would have thought (sea caves) you would look at water-jets instead. Even more need for more HP.
Anyway, best of luck with your venture.

[Robbie D]

Thanks for the reply, Brian.
The hull dry weight is just under 2000 lbs.
The merc 4.2L D-Tronic weighs in at just under 1300 dry weight w/ bravo 3.
Passenger weight will more likely be around 2300 lbs on average.
Plus fuel and miscellaneous, maybe 400 tops.
Total of around 6000 lbs. for a 7.5 meter RIB.
I could put in the same 4.2L D-Tronic in the new 300hp model with the same weight, but I've also heard the cons of motors which try to squeeze out every bit of hp from the same size engine block i.e. longevity. Anyone have any experience with the mercruiser 4.2L D-Tronic?

[tim griffin]

you might get some good advice from the guys atwww.seafariadventures.net
as they are in the same game as you,
regards tim
www.griffmarineservices.co.uk

[Brian]

Please, please get some more answers before comitting. My boat weighs just about 1000lbs above your projected load and I got through 2 x Bravo 3X legs. Each one failed after about 150hours.
These websites do similar trips to you:

http://www.seatrek.co.uk/
http://www.seafari.co.uk/
http://www.ramseyisland.co.uk

Or you might try approaching those membrs who post on the Commercial Forums here.



Good luck whatever your decision.