Inboard Sterndrive Vs Outboard

[choteo]

Hi All,

This topic may have already been previously discussed, however I’d like to hear your comment… I’m looking at a custom made Razerline 7.6m, Cuddy Cab, Enclosed HardTop, alloy plate hull. Weight approx 1200 – 1400kg (hull only)

My option are:

2 x 150hp Outboards (4 stroke)

1 x 260hp Inboard Sterndrive Diesel Turbo (Duo Prop)

While I love the thought of redundancy, I’m also looking at reliability, long distance and fuel economy….

What is your thought?

Regards,

JM

[a boat]

Hi, if I had narrowed it down to those two engine choices I would definately go the 260HP Diesel sterndrive. It will give you better range and economy and I would be surpirsed if one 150HP 4-Stroke of any brand would comfortably plane that boat if you had to get home on the one engine. We see it all the time with twin rigs, people underpower them and when both engines are running it is fine, but the point of twins is the safety of getting back on a single engine and if that engine struggles to plane the boat then there is not much point going twin engines with the extra costs and running expenses that come with twins. Also unless the boat has seperate fuel supplies, most modern engines that we see having troubles are with the fuel systems, so if both engine are running off the same tank than both with have the trouble.

As with any new boat, go for a run with twin 150HP 4-Strokes if that is what the dealer/builder is saying and see for yourself. Take a few mates and make sure the boat is loaded as you would have it and then trim one engine up and see what happens.

Just my 2 cents worth,

Huey.

[choteo]

Hi Huey,

Thanx for your opinion. I'm inclined towards the Sterndrive.... I comparing, Cummins, Steyr, Yanmar and Volvo. Cummins, Steyr and Yanmar come with the MerCruiser leg and the Volvo is Volvo. All Duoprop.

Do you have an opinion on the makes above? What about Duo vs Single prop? Any comments are appreciated. Thanx...

Regards,

JM

[a boat]

Hi JM, I have a limited experence with duo-props, but the boats I have driven with them do perform very well. They give you lower planing speed and better all round performance than a single prop like a Bravo 1 or 2 drive, but come at a cost to initally buy and maintain, but if you are trailing this boat and it is going to live out of the water and get flushed with fresh water I would be tempted to go the Bravo 3 or Volvo duo-prop.

I have not seen many Steyr so I can not comment on them, but the other players being Cummins, Volvo and Yanmar are all good units and I do not think you could go wrong with any of them. I would be leaning towards the Cummins myself because of the tie-in with Mercuriser and the fact that the parts supply and cost will be lower with this engine.

If possible you should get a run in as many of them as you can and then decide of what you like.

Sorry I could not be more helpful, but we mainly deal and service outboards here, even though we are Mercuriser agents, which we are seeing more of because of the cheap US boats evading our shores and the fact that they mainly all run M/cruiser.

Cheers,

Huey.

[choteo]

thanx for the advise.

Regards,

JM

[Boban]

Not having any mechanical training the following is based on my discussions with boat owners, charter operators and marine mechanics in the Whitsundays.

Let's just say that they prefer Yanmars over every other type of motor. They spoke in terms of fuel economy, reliability, initial cost and parts. The last conversation I had was with a mobile marine mechanic who services and repairs the charter yachts. He had a number of disparaging remarks about some of the other brands you mentioned and gave his reasons why they would not be his motor of choice.

I think the number of motors in service in the charter yachts is something like 90% Yanmar. I think that says enough in itself.

When I build a cat, that is what I will be powering it with.

[choteo]

Hi All,

Thanx for all your input. I'm inclined to 7.5 - 8m mono (Alloy Plate) with 270hp Sterndrive, Diesel Turbo charged. Thanx again...

Regards,

JM