Discussion in 'Props, Shafts & Seals' started by SandEngXp, Apr 5, 2011.
I still don't like them.
That film shows what could be argued as the best case scenario. It runs into a vertical immovable object and the shock load shears the leg off.
How about running it up on a real life pile of rocks or a shoal where it gets slammed around a bit at something other than 90 degrees to the cliff.
This has been up before: http://www.yachtforums.com/forums/117620-post176.html
And discussed a lot as you can see in my search: http://www.yachtforums.com/forums/search.php?searchid=645489
That second link doesn't seem to be active anymore.
Granted different circumstances may have different results, but running up onto a pile of rocks seldom has good results. With conventional drives and rudders you're quite likely to hole the boat or even rip the running gear out of the boat, and that hole won't be sealed. Personally, I love IPS. Between the fuel savings and the maneuverability their great. Certain bugs are sure to surface as time goes on though same as with any new technology. One thing that I wonder about however is, where are the crash, economy and maneuverability stats, etc. for Zeus? Have they reached the fuel savings of IPS? What happens when they hit something?
....Me neither. Fancy parts to break. Very expensive. Those things transfer power 3 directions, with duoprops at the shaft none the less. A shaft in a shaft. Too many moving parts.
Good idea from an autocad drawing, but not practical...Ships and tugs that use Z drives aren't cruising around at high speed in shallow water, such as a recreational vessel fitted with pods.
OK, but what is better with grounding a shaft and rudder boat that sinks..?
Anybody here ever have to replace shafts, props, struts and rudders and repaired the bottom damage after running into a rock? Fortunately, I haven't, but I suspect to will cost near the same as replacing the lower unit for an IPS. Then you have what's saved on fuel and the other perks. Better to just stay off the rocks with either.
Anybody here ever been asked by an Owner of a 70m yacht why his boat doesn't seem as smooth as when it was new a year before and then found when it was hauled that both props were beat up like rose buds and the only Captain who had ever driven it knew nothing about it?
.......Ignorance does get expensive! And can cost you a job among other things.
To be fair, one trip through NY Harbor will leave you a bit dinged and you'll never be near the bottom or rocks. I've been through there when you could almost walk from the Verizano to the Bklyn Bridge on the debris. We're talking everything from garbage cans to dock and pilings. Some dings go with using a boat. (A captain should notice when they're rose buds though).
Yea, Looks nice from idealistic standpoint, but any chance that will actually save a boat? I wonder if there are any reports of unsunk boats from the Penta Design.
I've seen outdrives ripped off as well as shafts and rudders, always leaving a big hole. Anything can be ripped off if you try hard enough. I do know of one IPS that nailed a sandbar. It sheared off and sealed as planned. Still curious if anyone knows about how Zeus handles this?
I'd like to see a video where researchers throw chunks of drift wood onto high revving IPS props.
I think the Zeus is a superior system, after running it extensively. You can do very finite adjustments with the zues because it uses the trolling valves, it's not just in and out of gear like the IPS system. The Zues props face rearward instead of foward like the IPS. Also the drive oil and all maintanence can be done IN the water, unlike the IPS which has to be out of the water to change the gear oil, and also no rubber bellows like the volvo. Supposedly they have the same efficiency whether the props are facing foward or in reverse. Also on the Zues the exhaust can be routed out of the transom, not sure if it can be on the IPS.
The Zues is designed to breakaway and the built in trim tab keeps the props from hitting the hull on breakaway. Providing you have the units it costs $3k to re-install both of them after a breakaway. The drive costs $20,000 if you lose it. If you lose a Volvo and don't have the core, you cannot get another one.
I only know the economy on the 40' Cabo. With 800hp MANS and conventional shafts it cruises at 31 knots and 60gph. With 600HP Cummins Zues it cruises at 32 knots and 45gph at cruise......25% better fuel economy.
However, I've heard that triple and quadruple installations on the larger boats are like 3 and 4 outboards on a center console......you get less and less returns % wise with the more zues or ips you have in the water, you still get 15-20% with 3 pods less than 10% with 4 from what I've heard from several people. Plus the downside of maintaining 3 or 4 motors. I think they need to design drives to handle more HP and do it with 2 engines.
Granted, I have little experience with IPS.
That's a day in NY Harbor, and I've come through with a few. NBD. Pretty much the same with whatever. If you hit hard enough to stop an IPS (or Zeus I'd imagine) you'd be stopping with a shaft drive as well. With anything you've got a few inches of protection whether it be the shaft, the unit or the cone. Beyond that it's just blades.
Capt.J, most info I've seen on the Zeus. Thanks. Can you lead me to a good site for Zeus info?
www.cmdmarine.com Cummins Mercruiser Diesel is the actual company behind Zues.......
It is always interesting with news and opinions on a product, so please post it here. But before we start repeating ourselves, here are already 289 posts on IPS vs Zeus drives:
We were thinking of having twin IPS900 instead of triple IPS600 in our 54', but they were more heavy, giving less speed and mileage at a higher cost.
For our coming 80' I am planning to have triple IPS1200 (the biggest available today) but perhaps we should just have two and reduce the top speed.
There are three sizes of IPS drives as you can see here:
This I do not know, I think part of it depends on the hull design and speed of the hull. As with any hull, the faster you push it, the more hp you need, and the more fuel you'll consume. I was just told the performance figures and efficiency from several captains, one of them ran a Lazzara with the 4 engine configuration. Several of them thought they were great on the smaller boats with the twin engine installation and that is where they thought they shined, not as beneficial in the larger yachts. One thought not worth the trouble above 80'.