Boat with Yamaha Diesel

[ontheplane]

Have found a used boat that somewhat busts our budget - but it comes with a diesel.

Given everything asked / written etc in these parts about diesel (they don't blow up, better availability dockside and longer range etc etc...) I thought I would ask a couple of questions...

1) Boat is approx 22ft, weighs 2000kg ish. Standard Deep V planing hull. Engine is the 175HP Yamaha Diesel with a single prop. Will this boat be too sluggish to waterski/tube/wakeboard from? Will it happily stay on the plane without being flat out all the time?

2) What kind of consumption should I be expecting from that engine on that boat at a cruise speed (realise that this will all be best guess) - but I know a V8 would be burning 5-10gph perhaps 12-15gph flat out - so how much better would this boat be?

3) If we pay a decent premium for this boat because it's got a diesel - will it still attract a premium when we're paying full price for waterside diesel, or will it only be worth a tiny amount more?


All in everyones Humble Opinion of course!

 

[volvopaul]

I will say a couple of things about yamaha engines and drives.

Very good engines, drive good if oil changed every year.

Bad side parts cost, worse than volvo.

 

[Spi D]

175 hp, even with diesel torque, will struggle with 2 tons+persons and gear + watertoys. Do the maths and calculate the ready-to-go weight with fuel and all.

As a rule of thumb, hp = weight divided by 10 will give you 30 knots in a planing hull of that approx size. Less hp needed if lighter...

 

[landlockedpirate]

Fletcher 22 ?

If it is, they are nice boat, hold value well and cruise nicely with the oil burner. But imho its just not enough to put the 'sports' in sportscruiser.

Give it a try, but having had a 19 with 190hp I wouldnt want any less for watersports. I would however buy 1 for general cruising.

 

[neale]

1) Boat is approx 22ft, weighs 2000kg ish. Standard Deep V planing hull. Engine is the 175HP Yamaha Diesel with a single prop. Will this boat be too sluggish to waterski/tube/wakeboard from? Will it happily stay on the plane without being flat out all the time?

My 25ft Bayliner has 170hp diesel and is good for 30 knots flat out and cruise at 25. The supercharger means it is not sluggish, without it I think it would be. Does the Yammy have a supercharger?

2) What kind of consumption should I be expecting from that engine on that boat at a cruise speed (realise that this will all be best guess) - but I know a V8 would be burning 5-10gph perhaps 12-15gph flat out - so how much better would this boat be?

Having had a V8 in the Bayliner before I can tell you that the typical consumptopn was around 9gph with petrol and around 5.5gph with diesel.

3) If we pay a decent premium for this boat because it's got a diesel - will it still attract a premium when we're paying full price for waterside diesel, or will it only be worth a tiny amount more?

Difficult call in a sportsboat. In a cruiser I think diesel will always command a premium. In a sportsboat I think it will be much less so.


All in everyones Humble Opinion of course!

NB

 

[Jim@sea]

A diesel engine is a lot heavier than a petrol engine so to have a sports boat with a diesel engine you will get less performance than the boat was designed for.
Jeremy Clarkson once said something like "Petrol was for Fun and Diesel was for work".
I havent ruled out buying a petrol boat. At the moment on ebay there is a 21ft Sports boat with a 210 v8 Petrol, Cuddy Cabin, Trailer at under £10.000. The seller is moaning that nobody is bidding on it. But thats ebay. I put an immaculate 1985 Speedboat (in time warp condition) on ebay and nobody wanted it But a Polish Boat dealer bought it.
Petrol boats are getting seriously cheap and if it costs £200 extra per year on top of what you would spend on diesel you would have got their faster and after 5 years you would only have spent £1000 more and still have a cheap boat.
Mind you there are brilliant outboards now. Is it Merry Fisher who are going out of Inboard Diesels and everything is the Suzuki Outboard.

 

[PCUK]

Neale, can't see that a supercharger would make any difference to performance apart from take off. Bhp is bhp no matter how it is produced.

 

[neale]

Neale, can't see that a supercharger would make any difference to performance apart from take off. Bhp is bhp no matter how it is produced.

The question wasn't so much about performance but about sluggishness. The take off that the supercharger provides is what makes the boat 'not sluggish' I had a problem once with the supercharger not kicking in when it should and I can tell you it felt very sluggish, barely getting on the plane.

 

[ontheplane]

Its a Chaperral.

Having looked, it's actually nearer 24' but it weighs 2000kg give or take.

We don't monoski - just need enough poke to use pair of ski's wakeboard or ringo.

Also would like to be able to cruise about 20-25kts and do the occasional watersports.

Nope there is no supercharger - just a turbo I think. I've often thought that a little electric motor fitted to a turbo with a clutch would be a good idea - just to help the turbo spin up quicker - not sure how you'd set that up though and I wouldn't be messing with such a pricey bit of kit....

I wouldn't mind particularly if I had to have 2 different props - one for cruising and one for watersports - but I DON'T want to buy it and find it can barely get on the plane like my last boat (145hp in 1800kg 23ft cruiser) - that REALLY struggled and once loaded up with a weekends cruising gear it really couldn't get up and get on the plane.

 

[JKay]

"Solitaire" ran a one of those Yams in a Fairline Sprint an it went really well might be worth a pm

 

[ontheplane]

Hopefully he'll pop up in a bit - he's a regular!

I'll PM him if he doesn't ta

 

[Latestarter1]

The question wasn't so much about performance but about sluggishness. The take off that the supercharger provides is what makes the boat 'not sluggish' I had a problem once with the supercharger not kicking in when it should and I can tell you it felt very sluggish, barely getting on the plane.

Just because Volvo Penta have always been poor at turbo matching please, please do not assume other manufacturers suffer the same affliction.

Simple fact is that YOU DO NOT NEED a supercharger for good out of the hole performance. Much of this stuff was smoke and windows marketing to cover up for a base engine which was a bit if a slug. The oversquare 40 Series really struggles to produce power low down, always a problem with short stroke diesel engines, you have to use throttle as a weapon!

On the other hand the Toyota base Yamaha M372 has pretty decent 102/112 bore stroke ratio which enables you to produce enough 'ows yer father' at the bottom end without resorting to whacky solutions.

I have been playing with compound supercharging on 2.8 four jug and 4.2 V6 marine diesel engines as well as 6.7 automotive engine and yes the results can be eyewatering, however much of it is to do with emissions.

The Yamaha is only 123 kW by the way......165 real horsepower! Only answer is to give the vessel a trial, if nobody telling porkies about weight, could just work.

 

[neale]

Just because Volvo Penta have always been poor at turbo matching please, please do not assume other manufacturers suffer the same affliction.

Simple fact is that YOU DO NOT NEED a supercharger for good out of the hole performance. Much of this stuff was smoke and windows marketing to cover up for a base engine which was a bit if a slug. The oversquare 40 Series really struggles to produce power low down, always a problem with short stroke diesel engines, you have to use throttle as a weapon!

On the other hand the Toyota base Yamaha M372 has pretty decent 102/112 bore stroke ratio which enables you to produce enough 'ows yer father' at the bottom end without resorting to whacky solutions.

I have been playing with compound supercharging on 2.8 four jug and 4.2 V6 marine diesel engines as well as 6.7 automotive engine and yes the results can be eyewatering, however much of it is to do with emissions.

The Yamaha is only 123 kW by the way......165 real horsepower! Only answer is to give the vessel a trial, if nobody telling porkies about weight, could just work.

Good info. Just to be clear I wasn't suggesting that just because my engine has a supercharger, all engines need one. I was simply giving a real world example to the OP as someone who has a boat of a similar size with a diesel engine of similar HP. It would be good to hear how this boat performs. If the Yammy/Toyota doesn't require a SC then I think the 165hp will be enough to cruise well below WOT. I tend to cruise at 3000prm against a 3800rpm max and achieve around 24 knots.

 

[Solitaire]

Hopefully he'll pop up in a bit - he's a regular!

I'll PM him if he doesn't ta

Read your PM. I will get back to you. I am about to go down to boat that has the 420's. My engine was a 370sti and it was great. I reluctantly sold the boat when I was driving other people's more than I had time to drive my own.

 

[Solitaire]

Here are a couple of pix of my now ex Fairline Sprint re-engined with the 370st Yamaha engine.

Top seed was around 32 knots when all clean and she cruised very comfortably at 24-26 knots. As to power for pulling a skier - never did but with a change in prop pitch - I ran at 21- I reckoned it would be OK, but don't have too many on board and not sat on the rear seat! I loved the engine/boat combination and would still have her but for the fact that I didn't use her enough as I was always teaching and on other people's boats.

I had the engine installed by Bill Brown and he always maintained her - best Yamaha man around - he devised a leg cooling system that was adopted by Yamaha. Although retired from running his own full time business (BBMS) - he is now chief bosun at the RAF Yacht Club, he still does a few "selected clients"

"Solitaire"