"This is what happens to an IPS propelled boat when it hits a rock!"

NYCAP,

If you believe you sold them on(to) Chris Craft and they were among the first to use them, you are quite torn with delusion. Best to study history before such a loose statement and equal self-promotion. In 2003, when the IPS concept was finding a home in its first US builder's hulls, Chris Craft was a long-fading brand looking for a savior, not a new power concept. Better fact here than fiction.

And again, one cannot only look at a product upon failure, but also who installs it, and how. Look into AFRI-CAT, for example, if you want to learn this principle.

Self-promotion? Talk about delusion. I don't sell boats or anything else except my services. However I do ocassionally help out at boat shows promoting a product. This was the Javits show in I believe '04 or '05 (maybe even '03). Chris Craft had found their savior and was introducing the IPS on their Roamer. Fact! I seem to recall one other boat at the show having it, but don't remember who that was.

You're right CAP, Julius & Heese were indeed in place before '03. My error, best bone up on my own history. But I believe the first year the Roamer was offered with IPS was 2006.

Back on target, this thread title and opening comment are quite misleading and irresponsible IMO.

No problem Capt. Us old guys are often off a bit on dates and people's names. There've been too many of them and very few that were important. We seldom forget good women or boats. I agree with you about the thread title as this may well be a pod problem and not just an IPS problem. They just have the big name right now and this did seem to happen to an IPS. I still think pods are the future, but this is a problem that needs to addressed fast. Maybe the break-away point needs to be an inch lower with a support ring above. DK, I'm not an engineer.

Looks to me like the hull to drive connection is the problem. The fixed part of the drive has tipped in the hull opening. There are some broken bolts or sheared fiberglass bits in there, most likely. I'm sure Volvo will want to see the procedures for installation as well as the laminate schedule in that area.
That type of movement should never happen. That's why the seal failed.
The drive to hull bolts / connection as well as the greater portion of the hull bottom must be able to absorb all the energy up to the point of the drive falling off.

I think that the design problem is similar to a downhill ski binding. The retention has to be strong enough to resist a high impact, short duration event, like bouncing off a mogul and at the same time protect against a broken leg caused by a slow twisting fall.

What we see in the pictures is like a slow twisting fall into a semi hard bottom, the peak shock loads were not enough to snap the drive off but the slower impact into a softer bottom created a higher total energy, causing a lot of deformation.

An old Senior Cheif I worked for in the Coast Guard always used to say "only drive as fast as you want to hit somthing"

I have demonstrated and taught on both the Zeus and IPS systems. Both are a ton of fun and easy to operate. At a boat show last year I had people who had never driven a boat docking within 5 minutes with the Zeus system. I found that the IPS system felt stronger. With the Zeus there was a bit of slapping and there was some stalling with a mistaken move. Both have very similar mounting and breakaway which, judging from the earlier pictures, needs some looking into. Someone recently told me about a guy who has knocked off 2 sets of IPS drives and it worked as designed although I have no personal knowledge of this. Forward facing props are slightly more suceptible to strike damage, but anyone who's ever hit knows that props always seem to find the object no matter if you're running inboards, I/O's, outboards or pods. Don't expect to see the skyhook feature from anyone until they can figure a way around the idiot factor.
And CaptEvan, who are you to tell anyone to "shut up" and why are you accusing everyone of being a salesperson for Zeus? Could it be that you sell IPS? Pods are the future and the more ideas, comments and competition the better for those of us who are buying and using and not selling.

The 40' Cabo has the skyhook feature installed in the software boat. I've been on in, but as of yet have never run either the Zeus or IPS

NYCAP123

Thanks for the info and for taking my post in the spirit that it was posted. Good information from someone who has done it.

They've had it installed in both IPS & Zeus for some time but as of last fall they hadn't activated it because they've got to cover themselves from the idiot factor.

I've seen it installed on both a 40' Cabo and a 45' Formula....... I'm pretty sure the dealer can activate the skyhook function with any computer each dealer has.........

Evan,

Your recent post has been removed. Subsequent responses (in quotes) have been edited to reflect the same.

Let's avoid confrontations and focus on solutions.

Last Fall I was doing demos on I believe it's the 36 Formula with Zeus and the dealer had a 45 Formula there with IPS as I recall. A friend/client also has a 35 Tiara with IPS from last summer. At that time the skyhooks were installed but weren't active; I heard because they had to find a way of avoiding liability in case some fool used it as an anchor while swimming or some such move. Maybe the lawyers have figured it out by now. Scares me though. I've known of boats that have gone 200 feet up on rocks because people thought autopilot was a good idea so they could go below for play time at 20 kts.. Talk about interruptus,

My apologies, poor choice of words in haste.

The insinuation of the now removed post I confronted was that forward facing props had a role in the grounding destruction, and that a Zeus system would have fared better. All it presented was an advertisement, thus seemed a bit opportunistic. While not selling anything, my little crusade for posting justice red-lined at overzealous.

I firmly believe both IPS and Zeus are wonderful innovations, as well as the concept in general as ZF endeavors to spread the love. While having had the opportunity to put over 10,000nm on one, I doubt my impressions would vary much with the other.

This thread could have been more fairly presented by sharing the facts and images without the wholesale judgment. Bottom line, no body wants a hole in their undersides and this incident will be an improvement opportunity for those involved.

BTW I have Cats, shafts & struts on my present boat and love them as well.

Welcome back Evan. You're right on all counts. There was another thread about IPS vs; Zeus a while back and, when it comes to damage from groundings it's very much speculation. I'd love to see the results of side by side grounding tests, but that's not likely to happen. So basically, if you hit it's expensive (well there's something new) with any drive. This thread would have been more appropriately called................POD propelled... It just happened to happen with an IPS which meant that the props bent one way instead of the other.

This thread is getting a bit too polite so I figure it's time to toss in some more fuel.

First, the IPS isn't really a POD propulsion system, it's more a Z drive, it's an azimuthing propulsion system. The prime mover is not in the underwater component so it is not a "pod" no matter how much the marketing folks want you to believe you are now driving a cruise ship.

Second, if a boat hits any submerged object - including the bottom - the part that contacts first will absorb the impact energy first. If that first point of contact is the structural element of a drive leg then the prop will be protected to a much higher degree than if it were the first to arrive.

Common outdrives swing upward when they hit objects in order to protect the drive system and props, if they were turned around so the prop hit first then the prop would be destroyed by impacts which would otherwise cause little if any damage.

To claim that it doesn't matter where the prop is located simply goes against common sense and history.

Yeah, I can see them calling it an "azimuthing propulsion system". Yes the first gets the most, but Murphy's law dictates that the prop will find a way to catch the ground no matter which way it faces. I am very curious about your view on why the drives pulled away from the hull instead of breaking off and what you think should be done to correct it.

Well, they call it an IPS, everyone else seems to be calling it a "pod." It's just a Z drive with a clever control system. It's an outdrive with a horizontal transom and DP dreams.

I don't have any more information than anyone else so it's just speculation but the photos don't show much evidence of contact with a rock. And, obviously, the loading on the leg was less than that required for it to fracture but more than the clamp rings or suspension could handle. That must be giving Volvo a bit of heartburn at the moment. It's a marketing nightmare come true. I bet they broke records getting that boat repaired and fitted with a new set of drives. Too bad the only thing faster than a frightened marketing exec is the internet.

This may have been the single type of event that Volvo didn't design for, a high speed contact with a firm bottom where the impact load is spread out over sufficient time to create bending loads that were less than required to shear the leg but more than enough to overload the rest of the mounting structure.

In any event, putting the props at the predictable point of impact on a small recreational boat is just plain laughable in my opinion. The small gain in efficiency hardly outweighs the high probability that such boats will, at some point in their life, touch bottom.

"accident happened in the early evening but by next afternoon the engines had been removed for repairs."