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Old 01 April 2016, 16:12   #71
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Country: UK - England
Town: Southampton
Boat name: SMH Rib / War Shot
Make: Ribtec / Scorpion
Length: 4m +
Engine: 10hp Yam / 150hp opt
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Quote:
Originally Posted by Iron Dials View Post
So, to ask a "how long is a piece of string" question of people's experience.....

Apart from the particular personalities of petrol v diesel I'm curious as to the general view on diesel inboards in ribs?

If a man was looking at buying a second hand daysil boat (eventually) that he might hope to travel a few hundred miles from home in a week diesel seems to be much more widely available if you aim for fishing harbours.
The three spots you can get petrol on E coast of Ireland are all within the Dublin bay area, so tankering petrol would be v necessary.

What's the max engine hours you'd accept? Are diesel engines assumed to have a finite service life? Assuming a reasonable level of service history.
Do rebuilt engines make you nervous or is that generally a good sign?
How do outdrives survive the non-judgemental love they get from weed and barnacles?

Are they noisy, smelly, slow, hateable beasts? Or smooth, economical, reliable and desirable?
Are they generally the preserve of commercial boats?

I was thinking something of at least 150 hp upwards in 6.5-7.5m.
And this is a longer term planning question rather than money burning a hole in my pocket tonight question.
I was looking for diesel 10 years ago at the last boat change. Great fuel consumption was the main draw. However, I was looking at 6.5m and back then diesel didn't really work. The engine choice for that size of boat was basically the 120hp mercruiser - which wasn't a great Engine and not really enough power for 6.5m. We tried a 6.5m Coastline with this engine and the hull was just getting into its stride as the engine ran out of puff at 30ish knots.
A Volvo Penta KAD32 in a 6.5m would have worked well.
Also the engine takes up a whole row of seats.

There are a couple of 7m coastlines in the dry stack near me with Volvo Penta D3 engines which seem to work quite well.

Volvo Penta KAD42/43/44/300 series engines I feel are ideally matched to a rib. Turbo to get the power allied with a supercharger for low speed torque to get you in the plane quickly. There were a couple of 7.4m Ribtecs built with these.
Drove a 7.4m ribtec with a Yamaha 4.4litre, 240hp. Ok once up and running but no go until the turbo spooled up.

I had some time driving Sunseeker superhawk 34s with both KAD300s and Yanmar 315s. Totally different beasts - Volvo boats felt as they should. Easy up on to the plane. The Yanmar boats were faster but the turbo lag was horrific. If you floored the throttles from a standing start it could be 20 seconds or more before they spooled up!

Depends what your budget is. The 370hp V8 twin turbo Yanmar should be a good rib engine.
Volvo Penta D6 with a supercharger as well as the turbo will also be good.
Each of these engine and drive packages will be at least 30k however, possibly more.

Hours - many thousands with good maintainance not a problem.
Rebuilt engine - OK as long as the person who rebuilt it knows what they were doing.

Stern drives. Horrible hateful things that just suck up money every year - but a necessary evil!
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Old 01 April 2016, 17:36   #72
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Country: UK - England
Town: Poole
Boat name: El Mono
Make: Ribtec 9M
Length: 9m +
Engine: Yanmar 315/Bravo III
Join Date: Aug 2012
Posts: 368
Whisper,

I put an IMCO drive shower (http://teaguecustommarine.com/em0011...ve-shower.html) on my B3 as the first thing after buying it, to try and help prolong it's life! I picked up one cheap secondhand from Dave Crawford Marine in Lymington.

Regards,

Paul
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Old 01 April 2016, 17:52   #73
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Country: UK - England
Town: southampton
Boat name: hydradrive
Make: yamaha
Length: no boat
Engine: sterndrives
Join Date: Sep 2012
Posts: 289
Yam hydradrive parts are still ready available , The last 2 months or so they have introduced complete drives again . Owners are still wanting there engines to rebuilt than re engine which more economical .
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Old 01 April 2016, 18:17   #74
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Country: UK - Scotland
Town: north ayrshire
Boat name: charlie girl
Make: reiver 3.8/regal3760
Length: 10m +
Engine: 40hp 2st 2x6lp 315
Join Date: Jul 2009
Posts: 1,502
Quote:
Originally Posted by Searider View Post
I was looking for diesel 10 years ago at the last boat change. Great fuel consumption was the main draw. However, I was looking at 6.5m and back then diesel didn't really work. The engine choice for that size of boat was basically the 120hp mercruiser - which wasn't a great Engine and not really enough power for 6.5m. We tried a 6.5m Coastline with this engine and the hull was just getting into its stride as the engine ran out of puff at 30ish knots.
A Volvo Penta KAD32 in a 6.5m would have worked well.
Also the engine takes up a whole row of seats.

There are a couple of 7m coastlines in the dry stack near me with Volvo Penta D3 engines which seem to work quite well.

Volvo Penta KAD42/43/44/300 series engines I feel are ideally matched to a rib. Turbo to get the power allied with a supercharger for low speed torque to get you in the plane quickly. There were a couple of 7.4m Ribtecs built with these.
Drove a 7.4m ribtec with a Yamaha 4.4litre, 240hp. Ok once up and running but no go until the turbo spooled up.

I had some time driving Sunseeker superhawk 34s with both KAD300s and Yanmar 315s. Totally different beasts - Volvo boats felt as they should. Easy up on to the plane. The Yanmar boats were faster but the turbo lag was horrific. If you floored the throttles from a standing start it could be 20 seconds or more before they spooled up!

Depends what your budget is. The 370hp V8 twin turbo Yanmar should be a good rib engine.
Volvo Penta D6 with a supercharger as well as the turbo will also be good.
Each of these engine and drive packages will be at least 30k however, possibly more.

Hours - many thousands with good maintainance not a problem.
Rebuilt engine - OK as long as the person who rebuilt it knows what they were doing.

Stern drives. Horrible hateful things that just suck up money every year - but a necessary evil!
Only downside of volvo d series is the need to plug in vodia everytime the engine so much as sneezes you hear many horror stories of volvos in cruisers having electronic gremlins I'd hate to think what they'd be like after a few years in the average damp rib engine bay
I'll stick with old school mechanical injection for now and put up with the turbo lag ☺
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Old 02 April 2016, 05:03   #75
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Country: UK - England
Town: Margate / Ramsgate
Boat name: Ballistic
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Engine: Yam HPDI 250
Join Date: Feb 2002
Posts: 2,835
Since this has turned into a "where can I get parts" thread I'll do a sales pitch on behalf of Ken /\ who I happen to know has a barn full of Yamaha diesel / hydradrive spares if anyone reading this is looking
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Old 02 April 2016, 08:58   #76
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Country: UK - Scotland
Make: HumberOceanOffshore
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Engine: Volvo KAD300/DPX
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IMHO there is a lot more to consider when considering a diesel installation than just 'this engine is better than that engine'. Water is the engine's enemy, internally and externally. I've seen diesel installations that are horrible after a couple of seasons simply because of an inadequate engine compartment and venting arrangement. And, there have been plenty of engine failures because of ingestion of water, either via inlet or exhaust. If you're on the Easdale cruise, ask Tony Hill about Ribcraft and Yanmar water ingestion. - Silly louvre air intakes. If you're on Loch Ness ask the guys running the 10mtr Humbers about water up the exhaust of the Volvo D6s. - No risers. Everything looks fine, until it isn't!

Compared to an outboard engined boat the diesel engine is vulnerable since it is largely below the water line. Also, the outboard engine is pretty much a sealed unit except for intake air but the engine bay has to provide this role in a diesel installation. In installations where the diesel exhaust exits below the water there is always water present within the exhaust system and therefore the possibility of back flooding through the exhaust. Even when this seems safe there is constant condensation whithin the turbo and exhaust system when the boat is at rest. The metals used are usually alluminium alloy and cast iron, both of which are not salt water friendly materials. Perhaps OK if monitored and the boat is in regular use but a consideration nevertheless. Then there is the rubber exhaust bellows, often at or below the water line, it'll have a life of only a few minutes without exhaust cooling water. - Poly bag around the drive, mussels growing in the raw water system. At the minimum an exhaust riser should be considered as very good insurance, if not essential.

I've run for a good number of years with these limitations but they've always been there as a niggle of vulnerability. Presently I'm redesigning my Volvo exhaust system to eliminate these vulnerabilities once and for all - peace of mind at last.... maybe.

There's a lot to consider. It can be made to be very successful but be under no illusion that the diesel boat is similar to a boat with a couple of outboards bolted to a transom.
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Old 02 April 2016, 10:13   #77
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Country: UK - England
Town: Mighty Penryn
Boat name: Little Joe.
Make: Avon Searider
Length: 4m +
Engine: Honda BF50
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Quote:
Originally Posted by jwalker View Post
IMHO there is a lot more to consider when considering a diesel installation than just 'this engine is better than that engine'.
Similar to the diesel/petrol car scenario, we can tend to focus on the cost of fuel and ignore the wider picture/costs.

Most of the issues that you've highlighted, also apply to petrol inboards, of which I've had a couple. When they go wrong, you can easily throw the purchase cost of a good size outboard at putting them right. Then, a few quid a year saved on fuel becomes a drop in the ocean.

I'll stick with the floating bombs for a few more years.
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Old 02 April 2016, 10:59   #78
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I doubt over a typical ownership even taking fuel savings into account it's cheaper running a diesel inboard than a petrol outboard unless your doing high hours
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Old 02 April 2016, 11:14   #79
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I doubt over a typical ownership even taking fuel savings into account it's cheaper running a diesel inboard than a petrol outboard
Yeah, but at least it won't blow you to kingdom come.
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Old 02 April 2016, 11:30   #80
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