Not sure if anyone has seen this, but here is the latest and greatest in inboard propulsion. No keel, the props pull the boat, not push, so they face the bow! They also claim 30% better fuel consumption. It looks like an outdrive, but it goes thru the hull, not the transome. I went to the boat show to see this motor on a boat, but none were there. So far these are for boats 30 - 50ft. I wonder how they handle hitting a potline or any rope?

http://www.volvo.com/volvopenta/na/en-us/#

the picture

Thats wild, your right about hitting stuff. you'll hit the prop before the skeg.

I don't get it though, its the same design, why turn it around????

Still it looks good, maybe its to new or to radical to be in boats yet.

You turn it around so the prop is in "clean" water, not the %($^($ed up flow around the gearbox.

Will be messy when you hit something...

I was just reading about this a couple of days ago. Very interesting concept. Kind of like front wheel drive on a car. Hitting things was the first thing I thought of too, but not really a small boat application I guess so it wont be used for getting tight with the rocks. Good performance numbers though.

You don't need to be getting cosy with the rocks to hit something. There's plenty of crap floating around out there in the ocean.

Amen... sheared a rudder off at the hull a few years ago running at night....:(

As far as hitting ropes and cords I wunder if you could or more to the point if they make a line cutter that would attach to a rig like that. I did read that the new drive is spose to snap off if you hit something and leave the hull water tight. I think it's a great idea they (according to the article I read) turn 30% tighter than any other drive out there.
I'm still not sold on them yet but for bigger boats they should be a good option. :btu:

In this months boatus magazine, there is an article on these and they ask "What happens if you hit something" -
if it is a soft hit on the bottom the skeg handles it, if its a major obstuction , the drive unit is designed to shear off cleanly :eek:
without any hull damage or water intrusion.

I am familiar with this style of propulsor. There are some advantages to shedding all that old inboard support structure, that is a big resistance maker and a rudder is poor at low speeds and terrible in reverse. Moreover you direct the thrust in the fwd direction instead of along a shaft at an incline. Clean water (props first) get you less vibration and a couple points on the eff curve.

Yeah impact is an issue but it is a small for the intended consumer. The initial runs show some benifit but wait till you see when they actually start designing hulls specifically for this (not just retrofitting inboards) AND get the props tuned just right.

IMO this will start getting really noticed when gas hits 3 bucks/gal this summer.

Eventually, I expect to see a nozzle or duct house the props and the props re-desinged again for a nozzle. The entire thing will rotate. This will get a few more eff points and not add as much resistance as you think, while providing the protection you are looking for.

*****FINALLY****** decent technology is trickling its way down to the consumer boat market.

Sandy,
Yeah impact is an issue but it is a small for the intended consumer

H'mm I've sheared off a shaft & prop twice in the last ten years or so. I'm sure it was lot cheaper replaceing the shaft & prop than replacing that whoe shebang. I'll predict that if they become popular the insurance companies are going to charge a substantial extra premium for them.

"I've sheared off a shaft & prop twice in the last ten years "
For you definetly, ever consider a navigation course? ;) )just kidding MM!! :laughs: I've dinged a few props but never cleaned it off completely (came close in moriches though). For most others wiping out the bottom is a pretty rare event .
Also, if you shear off the entire thing, it may not be destroyed. It is designed to shear off. cost of shear pin is about $1.00 :laughs: (just kidding) If you wipe off an inboards hardware, there usually is some damage to the hull, it is not designed to break free in event of an impact.

Most people that really wipe off shafts and struts normally end up on a reef (a la that large Sport Fisherman on Pigs) on the beach or sink altogether. This system, you actaully don't do hull damage if you wipe it off, the boat is intact. There may be an insurance rebate....lives are more $ then outdrives :)

Although exposure is an issue and I would not use a drive like this fishing tight to the beach, for a lot of boaters this is a good solution. (the sea-ray weekender types) There is no doubt about it in my mind, there are a lot more +'s then -'s with this system.:

with all the weight form the engine being in the bow, your boat would jump onto a plane quicker too...

The two times it happend I was more than ten miles off the beach, hit a log floating just under the surface. The impact broke the shaft and I lost the rear of the shaft and the wheel, no hull damage, because I was up on place, almost no boat in the water. Ironically, both times the struts were fine, I must have hit the prop behind the strut.

Eben, they aren't ahanging where the engines are mounted just the drive system, the engine mounts just in front of the drive.

I was pulling your chain MM. ;) No offense.

The engine can go fwd (via a jack-shaft) as well. But the 315 volvo has engine mounts in the same place as the 454 chevy block...gee I wonder who their target is?:rolleyes: