Diesel ribs?

[Andre]

There aren't any Quicksilver engines. Perhaps Willk had in mind Mercury Diesel. These are the QSD 2.0 QSD, 2.8, QSD 4.2, TDI 3.0 and TDI 4.2 and there is nothing wrong with these engines

[willk]

Originally Posted by Andre

There aren't any Quicksilver engines. Perhaps Willk had in mind Mercury Diesel.

You're not wrong! Mercruiser was the word I was reaching for. There are a lot of them kicking around over here on older/smaller ribs - just waiting to trap the unwary so I thought I'd warn the OP. My bad.

[Maximus]

Originally Posted by willk

You've been looking in the wrong engines

https://www.yanmar.com/media/global/...Zdatasheet.pdf

Could well be...
I'll cadge a go on yours in the Summer if our paths cross!
....Not tried a Big Goldfish either!

[Fender]

Originally Posted by willk

Wheezy 240hp old school Yanmar diesel on a 8m "sports" rib? Horribly underpowered - no wonder he was twiddling with the trim!

Try that same rib with a 370hp V8 twin turbo Yanmar 8LV

But then a little old 250 hp outboard on a 7.5 would be a lovely combination.................

[willk]

Originally Posted by Fender

But then a little old 250 hp outboard on a 7.5 would be a lovely combination.................

I'm not sure a 250hp outboard on a 8m Scorpion would be particularly scintillating either. IMO, your mate has a poor choice of engine if he plans to impress his buddies. Possibly suits him very well for offshore cruising though? Sounds like he'd forgotten to trim his leg down - there's no way that boat was going to get out of the hole trimmed up. I've tried that in an 8.5m with a Yanmar 315hp (4 up) and it was spectacularly unsuccessful. The combination of turbo lag and a 1/2 ton of iron in the stern made sure of that! Effectively the power comes at a rev you won't easily achieve off the plane - so you have to use the noggin - trim down, power on. So a lardy old diesel wouldn't be my choice over a petrol o/b, no.

To return to your mate's problem again - maybe a 260hp, maybe a 7.5 or 8m, history does not relate - but he was in bother not because he had a diesel engine, but because he had one with piss poor low rev performance.

My 370 lifts a 2.5 ton RIB out of the hole in short order, with the leg trimmed waaay out, with six people on board. I know this because I did it by accident last season!

[Fender]

Originally Posted by willk

I'm not sure a 250hp outboard on a 8m Scorpion would be particularly scintillating either. IMO, your mate has a poor choice of engine if he plans to impress his buddies. Possibly suits him very well for offshore cruising though? Sounds like he'd forgotten to trim his leg down - there's no way that boat was going to get out of the hole trimmed up. I've tried that in an 8.5m with a Yanmar 315hp (4 up) and it was spectacularly unsuccessful. The combination of turbo lag and a 1/2 ton of iron in the stern made sure of that! Effectively the power comes at a rev you won't easily achieve off the plane - so you have to use the noggin - trim down, power on. So a lardy old diesel wouldn't be my choice over a petrol o/b, no.

To return to your mate's problem again - maybe a 260hp, maybe a 7.5 or 8m, history does not relate - but he was in bother not because he had a diesel engine, but because he had one with piss poor low rev performance.

My 370 lifts a 2.5 ton RIB out of the hole in short order, with the leg trimmed waaay out, with six people on board. I know this because I did it by accident last season!

He'd not forgotten, if you check my earlier post you'd see he was working the trim to achieved the best acceleration ( I use the term 'acceleration' loosely ) and he said if he didn't keep on top of the trim the boat was even slower out of the hole.
Surprised you don't rate a 250 outboard on a 7-8m, you see loads around the Solent every weekend and, you might not believe this but some even on the plane Oh well, back to my buoyant explosive device

[Mollers]

Originally Posted by willk

My 370 lifts a 2.5 ton RIB out of the hole in short order, with the leg trimmed waaay out, with six people on board. I know this because I did it by accident last season!

Bet it looked dead pro outside of a busy waterside boozer on a nice summer's eve?

You fixing the embarrassed grin whilst turning the place white.

[willk]

Originally Posted by Fender

Surprised you don't rate a 250 outboard on a 7-8m, you see loads around the Solent every weekend....

You're no more surprised than me because I didn't say it! I specifically said 250hp/8 meters. There's a world of difference between 7 and 8m!

It might help if you could remember what size of Scorpion it was that you were on!

Try not to explode

[mick]

Not sure what make but it can shift

[beamishken]

The thing is you can't compare a petrol outboard with a diesel inboard as there so different it's like comparing a hot hatch with a landcruiser
Totally different horses for different courses

[Mollers]

Surely the best way to pep up yer diesel, is to drop another in beside it and let them have some fun together?

[rocknrolla]

Originally Posted by mick

Attachment 111632
Not sure what make but it can shift

i think that may b one of franky n bennyz Looey

[Zippy]

We had a steyr 256 in a 9 meter stepped hull cougar and it was about a close to an outboard as I have driven a diesel rib.

High 5 prop and very little turbo lag and never had a problem even towing skiers (mono ski / wake boarders)

The cougar was a light boat so would be comparable in weight to an 8.1 scorpion I would guess?

even with the cost saving for fuel, I would stick with a new petrol outboard but then my boating is in namby pamby south coast where waterside petrol is easy.

[Low Flyer]

Have Twin diesels in 8.5m great all round and economy to die for.


Sent from my iPad using RIB Net

[beamishken]

Originally Posted by Zippy

We had a steyr 256 in a 9 meter stepped hull cougar and it was about a close to an outboard as I have driven a diesel rib.

High 5 prop and very little turbo lag and never had a problem even towing skiers (mono ski / wake boarders)

The cougar was a light boat so would be comparable in weight to an 8.1 scorpion I would guess?

even with the cost saving for fuel, I would stick with a new petrol outboard but then my boating is in namby pamby south coast where waterside petrol is easy.

Probably the reason for the lack of turbo lag in that set up would be possibly partly due to the engines turbo set up which is smaller dia & will therefore spool up quicker than a yanmar 6lp which runs a relatively large diameter turbine & comp wheel.
But more likely due to you running the bravo 1 drive with a well matched prop

So many yanmar installations run bravo 3 duo props or bravo2 which is essentially a big cruiser leg with a big dia lower unit & huge dia prop which leads to very little prop slip on either drive which prevents the turbo spooling up to get the thing actually going
For a fast rib a far better set up is a bravo 1 drive with a well matched prop of which there are many variations unlike the b3 and b2 which your stuck with mercruiser's limited standard props

[whisper]

Tony the dude has advertised that Scorpion now, if didn't already have a diesel rib I would have bought this, I think the op should take a look at this:

https://m.apolloduck.com/feature.phtml?id=466213&z=ie




www.customrib.co.uk n

[willk]

Originally Posted by whisper

Tony the dude has advertised that Scorpion now, if didn't already have a diesel rib I would have bought this, I think the op should take a look at this:

Looks like Barrowboy's rib. Nice boat, but the supply of Yamaha parts may become an issue over the next couple of years - particularly drives/dive parts.

[whisper]

Originally Posted by willk

Looks like Barrowboy's rib. Nice boat, but the supply of Yamaha parts may become an issue over the next couple of years - particularly drives/dive parts.

Yeah that's the Barrowboy's

What's up with Yam parts?


www.customrib.co.uk n

[willk]

Originally Posted by whisper

Yeah that's the Barrowboy's

What's up with Yam parts?

I suppose it depends on the existing stocks if they're no longer being produced? Obviously there will be aftermarket stuff - but whole drives or very Yamaha parts like pistons could get tricky in the midterm. Unless you know different - I'm kinda out of the Yamaha loop nowadays.

[beamishken]

I'd imagine someone (if not yamaha) will do or start doing the service parts for the drives, bellows anodes gear cables etc
I can't see there being much demand for pistons etc as the engines once at that stage will be uneconomic to repair & owners will probably opt for used parts to keep old engines going
Drives are a fairly easy replace with merc bravo as they use same splines & transom drilling pattern
I'd imagine a yam powered boat should be a little cheaper than a yanmar but not a total nono