Revisiting O-1

[Willallison]

I've always thought it a bit of a shame that we never managed to get Option One to any real conclusion. But I'd like to re-visit one of the more hotly contested discussions that took place... that being the choice of power.
I was, and still am , a great advocate of outboard power, particularly for smaller boats. But there comes a cross-over point - not just in size, but also in vessel complexity - where other choices can start to make more sense. At around 28ft long, O-1 is probably close to this threshold. When you toss in other requirements - like hot water - is an outboard still the best choice.

In the couple of years since the O-1 thead dwindled, there have been enormous advances in marine propulsion. Not so much from a drive point of view, but certainly in terms of the engines themselves. 4-stroke and direct-injection outboards have really come of age, whilst advances in diesel engine technology now means that they are a viable alternative to their petrol sipping inboard/sterndrive cousins. New packaging ideas - like Mercury's 100hp Vazer - whilst probably too small for O-1, demonstrate that there's still life left in the conventional petrol sterndrive set-up too.

So - with a number of boats of O-1's sort of size and configuration being discussed in various places, what do we think now.....?

[marshmat]

I'll agree that Merc's new Vazer sterndrive is probably not quite enough for most of the O-1 concepts that have shown up here so far. But I bet it will catch on, big time- Vortec 1600 block, internals pilfered from the Alpha- good, reliable stuff that you can find and replace anywhere. If it were a choice between that and a 100hp outboard, I'd go for the sterndrive.
At the same time, outboards have been getting darned big. 250 hp is now routine and 300 hp outboards are popping up here and there- stock and with full warranty, no mods. So the size limits are starting to break down. But outboards, for the most part, are still engineered and built for light, high-speed craft. The electrical and heating requirements of a long-range cruiser do seem to favour an inboard of some form, not to mention the difficulty of performing mid-lake repairs on an outboard cantilevered a metre past the transom.
I think the diesel's Achilles heel is, and will for some time remain, its huge capital cost. In the size that something like O-1 would want, a diesel seems to come in at over double the cost of the comparable gas engine. That's a lot of extra dough. With diesel car engines all the rage these days (Volks TDI, Benz Bluetec, Smart, etc), we might see some mass-produced blocks suitable for marinizing that could come in somewhat cheaper than the current offerings from Volvo, Yanmar et al. The premium for a TDI or Bluetec-powered car is now only $3-5k over comparable gas versions, and that gap is shrinking. These are light engines but from what I've seen they are far from fragile.

[Willallison]

Even that barrier is being broken down somewhat. I just priced a couple of engines the other day. In Oz $ -
Merc Verado 150hp, 20K. 175hp 21.5K
Yanmar's new 150hp BY 4-cyl diesel with Merc's Bravo 3 drive is 23K

So the price difference certainly isn't that great. There's a weight penalty with the diesel - but even that itsn't huge...
The 150hp Verado weighs 240kg, the Yanmar 250kg (excluding the leg)