Which is the best Stern drive???

TIM · 08 April 2003, 21:59

This is something that is puzzling me a bit

From what I can see Volvo is the most common Stern dirve in hard Boats why??, And no one seems to fault there legs... ( they charge like a wonded bull for parts though...)

But in Ribs , Yanmar/ Mercurser combo seems the most common??

Also People have broken a couple of bravo 3 legs, but I havent heard of anyone breaking a Volvo duo prop leg.... well if this is the case why not use Volvos in RIBS then?????( I know some do, but why not more common)

And then there is Yamaha and Hydradrive.... Well Alan Priddy Proved that one, But he did go through a couple legs...

NOTE.... Alans legs seemed to die from heat and heavy loads. I heard of a guy in New Zealand in a fast commercial fishing boat with the same problem, On leg No 3 in 18months he dicovered by taking of the top cover on the leg and fitting a water spray hose over the top of Leg ( like the shower system on SOC) this Solved the problem and the leg is going about 2 years now without a hitch...????

SO which is the best???? and why

Richard B · 08 April 2003, 23:00

Quote:

Originally posted by TIM
Volvo is the most common Stern dirve in hard Boats why??,

- Heresay is that Volvo have a good scheme for large boatbuilders, something along the lines of "you pay us when you've sold the boat" - the ultimate cashflow solution for a builder who might have a million quid's worth of stock engines in uncompleted hulls - how could you turn that down if you're a boat builder? Even if it means that you only offer one propulsion system!

crazyhorse · 08 April 2003, 23:04

Tim we have all gone Volvo,

I have gone volvo New Kad 300 DPG Drive.

JW has gone Volvo New Kad 300 DPX drive.

Seafriskye has gone volvo Kad 44 not sure of the drive but its volvo.

We have all reserched the market this yr and last and decided for our own reasons that this gives us the best chance of getting what we hope are the best drives and engine combinations we could get for our new ribs.

There are others who have got Yanmars with 3x/2x that they felt was there way to go,we shall see over time which has indeed turned out to be the best decision

Alans leg I believe didnt fail cos they wore out but cos he hit a fish farm in it.He was doing extream milleage as you know.

The problem is if you want the best combination IMHO then you are going to have to be a bit unpopular to achieve it as the Trade will want you to have the engine they get the best deal on,not nesesarily the best engine and leg combination for you.

I hope this helps and feel free to email me if you want to get to the real nitty gritty.

Ps As far as I am aware none of us above have decided on Volvo Kads for the above reasons

Richard B · 08 April 2003, 23:22

Quote:

Originally posted by crazyhorse
I have gone volvo New Kad 300 DPG Drive.

- Really? Well, I'd never have guessed

But seriously, from Alan's book didn't he reckon that poor fuel quality had a major contribution to drive leg reliability (resulting in higher combustion temperatures)

Anyway, have you ever used a Yamaha Hydra Drive?

They are lovely

being from an engineering background, I love them... none of this "crunch" as you engage gear, just a smoooooth transition from neutral to drive... just like a Merc auto box!

crazyhorse · 08 April 2003, 23:52

Pepper what engineering background and experience have you on the Hydra Drive.We went for the New Kad based on reports from people who were using them day in and day out.And the Trade and press and what we could see for our selves.

So tell me Pepper Given your explanation of it goes into gear smooth what are these enginering bits that make it very good?

Have you owned one? If so what boat and how many hours you done and what do you base the recomendation on?

Have you had any problems and what is the service like.

AP recomends them as he has been round the world on them

But forgive me for being a little scepticle on your recomendation but please explain your case.

Richard B · 09 April 2003, 00:01

No, I don't own one... otherwise it would be on my profile over there

<===================

wouldn't it?

And I ain't taken one apart - that would just be foolish, wouldn't it... I'd be no more likely to take a yamaha hydra drive leg apart than I would to stip down my merc's auto box. I just know what I like, and enjoy using things that work correctly and feel "right".

As I said, anything that don't go "crunch" as you engage gear has got to be good!

crazyhorse · 09 April 2003, 00:09

Pepper please dont take this the wrong way but when your spending more than the cost of your new Merc car on an engine for your boat.

I promise you you look into things a little bit more deeply than if it dont go crunch when you put it in gear it must be ok.

But all opinions on this subject are of interest.

Thanks Pepper

Phill · 09 April 2003, 00:14

Certainly used a Volvo duoprop leg that has self destructed. Have to find engine/leg details for you tho' - cos it (fortunately) wasn't one of mine, I was just the semi regular coxswain - can tell you where the dipstick, inlet filter etc. is tho' !

Dirk Diggler · 09 April 2003, 09:57

Quote:

Originally posted by Pepper
But seriously, from Alan's book didn't he reckon that poor fuel quality had a major contribution to drive leg reliability (resulting in higher combustion temperatures)

I'm a bit confused by the above statement, why would poor fuel quality cause drive failure?

Using Alan Priddy as an example doesn't really stack up, last time I was at his place he seemed to have rather a lot of drive parts, and he is a gearbox specialist, and was sponsored by Yamaha.

A better example of Yamaha drive reliability might be the guy with the twin installation in a Delta, based at Drivers Wharf. He has done an amazing amount of miles with this boat, but has gone through an amazing amount of drives!

I suggest you ask him what he thinks of them!

As for Volvo drives being the choice of most British boat builders, I think you will find that the Engine is the deciding factor, and you then use what ever drive this comes with.

Volvo just happens to have an excellent choice of engines in the 2-300hp diesel range, best suited for 30+ foot cruisers, where as the Merc range is crap, IMHO and the Yanmar good but not suited to the Merc drive for reasons to numerous to mention.

Alan · 09 April 2003, 10:15

Thats presumably Jim Mackintosh and Still Deep One Too. And yes he has done a helluva lot of miles on his Yamaha's and hydradrives and swears by them.

Brian · 09 April 2003, 10:45

Xcuse my ignorance, but what's a Hydradrive?
Is it the same as a waterjet?
Or how does it difer from a "normal" drive leg?

Julian · 09 April 2003, 12:40

Hi Brian

The Hydradrive is Yamahas gearbox basicly, just like you and me have the Bravo 3 x leg, Yamaha have the Hydradrive. Its a very smooth gearbox and runs very well.

Julian

Brian · 09 April 2003, 12:50

Julian, thanks for that.

PS YOU MAY have a Bravo 3x. I now have a Bravo 1 with a 4-bladed left-handed prop.

I must say I feel a bit more confident now about running way off-shore.
There was a time when I felt I shouldn't go on any long-range cruise without taking Hot Lemon 4 along as my support boat!!

Daniel · 09 April 2003, 12:55

I quite sure as peper said the HydraDrive is similar to an automatic gear box in that when it engages gear it's not cogs interfering together, rather hydrolic fluid flowing through valves and things. This removes the crunch we are all so used to. I don't know any more about it than that though.

What i do know is Alan P did have problems with the unit, caused by overheating, which was, in turn, caused by poor quality fuel.

The reason - simple i guess (and i am guessing here) but don't nearly all of us have exhaust's that exit through the prop?

Poor fuel = inefficient combustion = hotter exhaust gasses per HP = boiling hydrolic fluid in said gearbox.

Julian · 09 April 2003, 12:55

Brian

How does the performance compare between the Bravo 1 leg and the Bravo 3x that you used to have. I know what you mean about running ofshore on your own with the Bravo 3 leg, its a bit worrying at times, Touch wood mine is still going strong (for Now at Least ).

Julian

TIM · 09 April 2003, 15:25

The Title should have read WHICH IS THE BEST STERN DRIVE, But the the other half was bending my ear, for spending hours on the internet.....

< It does now! JK >

DIRK..... Please name a few reasons why the bravo units are not suited to Yanmar engines......

It appears to me that Volvo and Yamaha are taking the lead on this thread..... then why are Yanmar/ Bravo units seem to be the most common?? Is it price???

But I think now its heading towards which leg you have, that seems the weak spot... in Diesel inboard Ribs

Alan · 09 April 2003, 21:33

I believe the 300 Yanmar / Bravo 3 (x) combo is so popular cos it offers the best power to weight ratio. IIRC the KAD300 is only about 285hp whilst that Yanmar is actually about 320.

I can offer no ownership experience of outdrives but I having done lots of miles with Brian on Cyanide and being there 25nm out of Stornoway when the second B3x drive failed in a major way I would not for a moment use this combo for extended cruising in a single engined RIB. The risk of failure would be too high for my own peace of mind.

As I posted earlier, Jim Mackintosh has done 1000's of miles on his Yamaha drives and has absolute confidence in em. I'd trust his judgement and experience.

Volvo's are widely prevalent in the gin palace market so must be a reasonably reliable product. Although not cheap I hear, but then what the hell is when we are talking about big RIBS!

-<=[Tw18]=>- · 09 April 2003, 23:31

ok so what are the differences between the bravo 1 and 3 that render the 3 less reliable and the 1 a better choice??

i presume price has a big part to play, but what technical aspects deem this?

Richard B · 09 April 2003, 23:41

Quote:

Originally posted by Daniel
The reason - simple i guess (and i am guessing here) but don't nearly all of us have exhaust's that exit through the prop?

Poor fuel = inefficient combustion = hotter exhaust gasses per HP = boiling hydrolic fluid in said gearbox.

Thanks, Dan - it's confusing for people with silly names. They have problems keeping up with our simple logic

jwalker · 10 April 2003, 00:36

The reason - simple i guess (and i am guessing here) but don't nearly all of us have exhaust's that exit through the prop?

I think you'll find that most Yanmar/3x folk expel most of their exhaust through the transom and 3x drives fail. There has to be another factor.

How does poor fuel quality increase the exhaust gas temperature?

JW.