Diesel engines.

[terry]

I am planning to start rib cruising off Queensland coast of OZ and am working on purchasing a suitable boat. As regards engines I was thinking the better arrangement for safety/reliablity would be two petrol outboards. But of course the running costs against diesel is significant! When I read your articles about crossing the Atlantic with a diesel rib I wondered if this might be a serious alternative.

What are the comments on buying a 2nd hand rib fitted with an inboard diesel via outboards petrol.

Ps excellent website John.

[John Kennett]

This is a question that often comes up, but despite the initial attraction of a twin engine installation, they tend to be quite rare in practice.

The exceptions are lifeboats and fast rescue craft who absolutely must keep going at all costs, and large RIBs in the USA where petrol is cheap enough to make a pair of 250 hp outboards viable!

For serious cruising boats a single diesel engine is becoming the preferred choice. Diesel is often more widely available at the quayside -- wherever you have fishing boats you'll find diesel -- and lugging hundreds of litres of petrol in jerry cans is no fun!

Diesels tend to me more fuel efficient than outboards, although with the new technology the gap is barrowing. In countries where marine diesel has a lower rate of taxation like the UK the cost benefits are huge if you do a lot of boating (it's also psychologically comforting to fill up cheaply each time, even though you may have spent substantially more buying the boat in the first place).

With a twin installation there is twice as much to maintain, as well as twice as much to go wrong! A twin installation is also less efficient than a single of the equivalent combined horsepower (eg 2 x 100 hp is roughly equivalent to a single 150 hp in performance terms).

A well maintained diesel engine is a very reliable piece of kit these days, especially when fitted with a substantial fuel filter and water separator to cut down on the chances of fuel problems.

You could always carry a small outboard as a reserve engine. This has it's own problems of a separate and limited fuel supply, plus secure storage, but is quite a common solution. I suspect, however, that quite a number of these engines get very little maintenance and may not be up to the job if things got serious enough to really need them.

A few of the bigger RIBs have been fitted with twin diesels, but this is out of the scope of most RIB cruisers!

A final option is a diesel outboard as a reserve. This avoids the problem of carrying a separate petrol supply, but they are very heavy and not widely available. This is the option that Alan Priddy has gone for in "Spirit" his round-the-world RIB.

What are the conditions like off Queensland? Will you be on your own, or with another boat?

John

------------------
John Kennett
RIBnet

[terry]

Thanks John for the very thorough and informative reply.
The Queensland coast with the great barrier reef has a mulitude of possiblities. The Ocean can be rough between the reef and some of the bars(not the liquid sort)on the edge of the estuaries still can be challenging.

The coastline can often be quite long without harbours, so a good range is useful (and reliable kit) So far I have not yet found the same interest in ribs that has developed in Europe....this is really sad as the scope for some excellent trips is endless. But I will be working on finding/developing more local interest. Certainly the mass of information available on your web site is a great help.

Being orginally from Portsmouth, I have followed with (jealious) interest all that you have going on....not so sure about your weather...perhaps its not just the boats that have to be tough! At the moment I just have a 4m avon inflatable which I used for simple trips in the outback and Africa. But for the Ocean I am working on the next stage which is searching out a good 2nd hand rib from the UK (your market is much bigger for robust ribs).It is not so expensive to ship it back in a shared sea container.

In Oz petrol outboard support appears easier to find (where I am ) than diesels engines, and petrol is a more reasonible price. But you gave some good reasons why diesel and this is the direction I would like to go. From your experience can a specialist diesel (vehicle shop) handle them?
Talking about support, if I need to get a rib repaired should I be looking when I buy one at a rib which has a agency in Oz or can they usually do goods repairs on most makes?

I have a few dozen other questions so will come back with them.....regards and good ribbing.

Terry

[John Kennett]

RIB cruising in Oz sounds superb! Make sure you let us know about how you get on. There are loads of places around the world that would be ideal for exploring in RIBs -- the Caribbean, the Florida Keys, New Zealand -- I'm sure the idea will catch on world wide before too long.

Buying a second hand RIB in the UK and freighting it across does seem to be the best plan, people just need to get to grips with the idea!

As to servicing a diesel, they are not wildly different to car or truck engines -- most of them are based on automotive blocks anyway. I've just had a turbo rebuilt by a car turbo specialist for about half the price that Yamaha would have charged.

So long as the tubes are hypalon, tube repairs are generally a fairly straight forward gluing job and the techniques won't very much from one manufacturer to another. Repairs to tubes that have welded seams will need a more specialist service. You should be able to get GRP repairs done just about anywhere that mends boats.

Have you decided on what sort of RIB you want to go for?

John



------------------
John Kennett
RIBnet

[terry]

John,

Thanks for your advise, I also think the whole rib scene has considerable room to develop and expand further..... certainly in Oz their is excellent potential. With 90% of the population close to the ocean, where already the sea and boats enjoy healthy followings. I was thinking an article about rib cruising in one of our boating machines would be a good start, also something like a rib expedition around the Australian continent would go someway to sparking interest.

As regarding what type of second hand rib I am looking for, that is certainly difficult from here where we do not have anything like the UK selection. I try and read any article I can find that describes the performance of a particular rib. Their seems to be endless possibilities, for crusing here I was looking for: something strong and robust, with a proven record, manufactured by a company that supplies the military/commercial users, designed for off shore work .....perhaps ex-North Sea/fire service rescue boat, about 7 meters, 150hp inboard diesel, internal tanks 150 plus miles range, hydraulic steering....(ideally not bright, bright orange!) The boats companies that have caught my eye are Halmatic with their Pacific 22, Zodiac Hurricane range and of course Ribtec.

It would be certainly interesting to learn more about from other rib.net followers what cruising ribs they use and how they have fitted them out.

Regards, good ribbing