[CODOG]

I'm not asking the question, but I'd be very interested in seeing your take on the centreline engine / keel treatment one day. There's a few reasons why I shouldn't, but the interest is there.

[AMG]

Absolutely, as soon as it is launched!

The fact is, I have several ideas but nothing is in my computer yet. I think this must be tank tested, even if I have no idea what I will look for...

My main concern is not to achieve the speed, but building a light boat that also has a smooth ride in rather heavy sea. It must also be as silent as possible, which always is a problem with a light and covered boat where the noise from hitting the water at high speed can be pretty annoying...

[NoRudder]

This thread has gone on a long time now. Very interesting indeed.
AMG, your point over triple 600 vs twin of the new IPS 2 is interesting. But I am so curious about the need for a "tank test". It is my understanding that Volvo Penta has been very open in support for designers/builders through the BEIC (Boat Engine Integration Center) and with the relationship with Donald Blount that many questions have already been answered regarding triple and quad installations. Certainly information on the new higher horsepower like in the Lazzara 92 is harder to come by so far.
Another item of note is the power options offered in a new boat. I was there to witness the shock when members of the press asked Dick Lazzara what other power options were offered in the LSX 75 besides quad IPS. The answer was none. If the system is truly superior to traditional shafts, then why continue to offer the option? This is an old thing with boat building that I am so tired of. Having been on the customer service side of things for many years, boats with less than optimum power options should simply not be built. We would all be better off in the industry. With POD drives, the new engine room arrangements and added staterooms in many cases make it clear that you need to dedicate the design to take every advantage possible and forget the old way.
This is what is selling POD boats, added live-ability, using less fuel, less smoke, quieter operation and joystick. Now Yanmar announced a joystick for their new sterndrive (in about a year) to follow CMD and Volvo Penta.

Sorry, I got carried away. I have extensive experience with the old and the new. I think we are going in the right direction.

[AMG]

The need for tank testing is more to find out the hull resistance with different loads as I intend to make something very different and special for this power option. As you say, it will be only IPS since all is built around them.

Personally I like sterndrives better, for many reasons, but except for a small power increase I don´t expect them to compete with the POD drives when it comes to boats above 50 feet.

[NoRudder]

AMG, certainly a valid point. The arrangement can make significant changes in the LCG and other important matters. It deserves the proper investigation.

The POD drive is not really designed as an alternative to stern drive, but really to bring stern drive efficiency to the inboard boat market. Stern drive already has directional thrust and underwater exhaust that the inboard has not had. But it also has not had independent steering for example that led to the joystick option. It also has severe limitations regarding exhaust flow and the ability to handle higher torque loads. The joystick application is simply being adopted from the pod drives to the stern drive market to help overcome issues related to docking. But engine center-lines are typically narrower as well which may complicate matters.

I also must note that those outside of North America will deal with Volvo Penta through their Market Regions, not the US branch. So the BEIC I mentioned is mainly for those in North America. Just to clarify the point.

[Dan Evans]

Hi everyone, please allow me to butt in with a question that has concerned me since these drives first came out. Are they built to break away from the hull clean leaving it still watertight incase of an underwater collision or are they going to rip a chunk off your hull? Sorry if this has already been brought up.

Dan

[Capt J]

Originally Posted by Dan Evans

Hi everyone, please allow me to butt in with a question that has concerned me since these drives first came out. Are they built to break away from the hull clean leaving it still watertight incase of an underwater collision or are they going to rip a chunk off your hull? Sorry if this has already been brought up.

Dan

Supposedly, they are supposed to break away and leave the hull intact. I have never seen one that ran across a reef, so I couldn't say for sure.

[NYCAP123]

"Are they built to break away from the hull clean leaving it still watertight"

They are made to break off clean and leave the hull sealed. It's ironic that that seems to be most people's first reaction (myself included). Meanwhile most of us know what happens when you rip the shafts or rudders out of a hull.

[Dan Evans]

Thanks CaptJ and NYCAP123. The drives breaking off was my only concern about them. Hopefully this will never happen to anyone on yachtforums but maybe if it does they will let us know what happens.

Dan

[K1W1]

Hi,

Go back to Page 1 of this post and read a few posts from No 5 onwards.

There are two stores of broken drives and a link to another YF Article

[Blair]

Originally Posted by K1W1

Hi,

Don't bank on being able to plane with just 3 of engines/drives working.

I spent a bit of time running a 3 engine Sunseeker Superhawk 52, twice we were down to two engines (66% power remaining ) and both times we were unable to get her on the plane and had to limp along at about 10 kts.

With multi engine apps however you get a wide range of suitable speeds and loading condition for the engines running.

Maybe the 4 engine boat wants to speed to the fishing grounds and then take it easy on two while they drag the gear?

Salthouse have a very good reputation and I have done a few miles on a Ketch they built in the 80's, I for one am looking forward to their 4 drive motorboat project.

The Salthouse Marine Group website has some informative stuff and links to articles on their first quad IPS driven 65 footer - and another one is in build. It seems that when trolling at least the craft works well with two of the 4 engines going. Another NZ builder, Genesis Marine is heavily into IPS options and their market seems to be convinced about the advantages.

There's quite a bit of reference being made to joy stick control and that is a great advantage available for most steerable drive systems I understand. Jet boats have used this for many years now, after original development was done for Hinkley's I think, but it has now extended into much more varied military, commercial and now other recreational applications overall and not just with jets. Nothing new or exceptional about such controllers being now adapted for drive systems IPS/Zeus therefore or at least not as much as marketing people would like us to think. These days such steerage innovation is often also coupled with dynamic positioning capability using GPS input, particularly useful for military and commercial users. Just observe the huge cruise ships with their steerable pod drives and thrusters manouvering in close quarters or just staying put in one spot without anchoring under 'hands free' control. It's just money afterall as is probably most evident when you see the high end superyacht tenders being built recently that dance in every direction or stay put under a 'sky hook'. Become a good boat handler after 2 minutes tuition? It ain't natural but eminently safer!

[NYCAP123]

"Become a good boat handler after 2 minutes tuition?"
That's what the sales staffs want people to think, but that's also what's holding up the "dynamic positioning capability" for recreational craft. When you dumb it down far enough it's hard to then say you have to think enough to maintain a watch and manual control. (While we wait for the bridge let's go below for lunch. ) I expect that the joy stick will catch on more and more, but I kind of hope that automatic station keeping doesn't (except on professionally manned vessels).

[Blair]

I actually fully agree with you - just like the a...holes who set an autopilot in busy waterways whilst doing 20+ knots and then pour themselves another gin.

[NYCAP123]

Oh, you've met him too.

[FISHTIGUA]

Volvo offer IPS with 2 options for the EVC-C2.

One is slow speed throttle control, just click into gear and the hydraulic clutch slips at just the right speed. The other is a traditional trolling option.

These programs are an aftersales option but I think most builders should fit them as standard. The Vodia programs also activate a joystick control anywhere you wish to put one. I'm starting to like them (that from an old-school boat handler like me is saying something).

One further issue is that IPS has an active corrosion device, like the Mercathode system, that uses Aluminum anodes. They are designed to fizz in the water, builders are still fitting Zinc ones right next to them and wondering why the Ally ones don't last? DOH!!!