Which engine for chugging about in?

Zagato · 23 September 2011, 06:49

I am either going to get a 6m RIB with a 90HP or 6.5 with 115HP or slightly larger. I would like an engine just out of warranty so I know it has been serviced properly BUT I want something frugal with fuel equally capable of chugging around at 8 knots in Chichester Harbour as well as occasional blasts out in the Solent!

I was very impressed with the Suzuki 90HP yesterday, sooo quiet but would really like to go up a size in boat to a 6.5m. If i get a Humber 6.5 a 115HP is recommended by Humber but the fuel shoots up on one of those as it doesn't have lean burn and is a bigger engine block

They probably don't go back 4-5 years anyway.....

Any suggestions for a good reliable engine that will never really get thrashed? 125HP maybe, other wise I'll get a 90HP something and a 6M RIB!

Leapy · 23 September 2011, 07:03

Quote:

Originally Posted by Zagato

I would like an engine just out of warranty...
I was very impressed with the Suzuki 90HP yesterday...115HP is recommended by Humber but the fuel shoots up on one of those as it doesn't have lean burn and is a bigger engine block

The 'lean burn' 1502cc Suzuki DF90 was launched at the Southampton Boat Show 2008 so all those engines are still in their 5 year warranty.

The Suzuki DF100/115 are 1950cc and not advertised as lean burn as you say. But, they also weigh 35kgs more...

If most of your cruising is lowish speed (you say it'll never get really thrashed) do you need the extra hp/weight/cost/fuel consumption?

willk · 23 September 2011, 07:54

Sounds to me like you need a small diesel inboard (merc 140/170hp?)

90hp would be fairly pants on that size of RIB and certainly not attractive if you were reselling. The diesel would happily creep around all day and still be fine for faster cruising. Fuel efficiency would be very good. Obviously you'd be paying a premium for it, but resale values should be good?

9D280 · 23 September 2011, 08:39

Or buy an 8-ish Hp aux & use that for the slow speed stuff?

dnv · 23 September 2011, 08:46

Quote:

Originally Posted by willk

Sounds to me like you need a small diesel inboard (merc 140/170hp?)

90hp would be fairly pants on that size of RIB and certainly not attractive if you were reselling. The diesel would happily creep around all day and still be fine for faster cruising. Fuel efficiency would be very good. Obviously you'd be paying a premium for it, but resale values should be good?

Can second that. Have a Parker 630 with the old 1.7l Merc tdi.
My fuelconsumption is 17h/l when blasting WOT in heavy weather out in the North Sea. The total average FC incl going offshore in a blast is 8.6l/h. Excluding offshore it is 5.9l/h.

Its both less fuelconsumption, and cheaper fuel. Further, you'd get Diesel anywhere.
In addition the feeling of being in a real ship :-)

Jan

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Leapy · 23 September 2011, 09:42

Quote:

Originally Posted by dnv

My fuelconsumption is 17h/l when blasting WOT in heavy weather out in the North Sea.

Now that's impressive

Or, a typo...

willk · 23 September 2011, 10:01

Forgot to add, no meaningful restrictions on transport or storage of fuel either...

dnv · 23 September 2011, 10:02

Quote:

Originally Posted by Leapy

Now that's impressive

Or, a typo...

No typo. Bookkeeping.
To be fair I need to mention the revs - 4100 WOT, 3400/3700 cruise. The FC is pretty much inline with the data supplied from Mercury
The max rated revs of that engine are 4400, but I've never seen them :-(

However, averaging 18kn over ground (against 25-30kn wind and against a 2kn tide with 2.5m breaking waves) over 2hours at 3500 revs is good enough to me

Jan

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