Discussion in 'Hinckley Yacht' started by misterT123, Dec 26, 2011.
I wish more comments were based on real world experience than googling and gossip...
I understand the cause and effect, but in the limited number of IPS installations I've run this has not been an issue.
Ok...i have been boating since over 30 years. I am friend with few boat builders and few boat racers. I tested tons of boats, from friends and from yards. I had boats with shaft and with surface (ips only tested many times and never liked them). Is that googling or gossip or it is real life? You tell me. I do not like ips system because i think disadvantages are much bigger than advantages...said so...someone likes fat women someone slim someone with small boops someone with big ones...if ypu like ips just go for it
You may have, but you're still woefully lacking in knowledge of IPS. It's fine as you say to like or dislike. I'm not a huge fan of IPS and when I had the choice on my last boat, I chose shaft. However, I'm a fan of the boats AMG designs with IPS. But here are some specific points I'd argue with.
1) main aspect is the hull : a hull must be made either for shaft, or for surface or for IPS.
Be very careful if a boat builder offers his boat with multiple choice of propulsion, for sure some of them will not work properly.
In general I'd agree with designing the hull and the propulsion together. However, I've handled a boat identical except on had IPS and the other shaft and it worked quite well on a hull that's used shaft for years.
3) this bring us to consumption : for sure IPS might be slightly better than shaft, but not as much as Volvo advertises. Mainly the differences in consumption come from the shape of the hull : more you increase the deadrise more you increase the consumption, and difference with the same hull between IPS and shaft is no more than 5% (and remember that fuel consumption it is not the voice that bring high the general running cost of a boat)
Just not true in my experience. I'll use just one of many examples I have of a boat with both IPS and shaft options. This is a Sunseeker Manhattan 65. Fuel consumption of 1000 hp MAN vs. 1200 MAN vs. IPS 1200. At 24 knots, a nice comfortable cruise for all three. The 1000 MAN uses 298 lph, the 1200 MAN uses 260 lph, the IPS uses 191 lph. This is real world. 36% less than the 1000's and 26% less than the 1200's. Yes, the 1200 does get better economy at that rate than the 1000's. Looked at another way, I'll take all three at 75% load. The 1000 uses 290 lph and goes 23.6 knots so 12.3 lpnm, the 1200 uses 332 lph and goes 26.5 knots so 12.5 lpnm and the IPS 1200 uses 230 lph and goes 27.6 knots so uses 8.3 lpnm so 33% and 34% more efficient than cruise.
4) about joystick : if you have a bow and stern thrust you can have a joystick also with shaft (Xena or Yachtcontroller for example), so zero difference in maneuvering.
True only if you have DPS as well as part of your system. The handling is very similar but there are features with IPS that some other systems don't have. We do have it all with shafts but that's not standard.
5) IPS are much more expensive in maintenance, almost double than shaft.
Perhaps more expensive but more in the low percent difference and definitely not double.
6) IPS is like a big hook under your boat : system detaches in case of hitting against something, so you will not sink, but you remain without the pod........
I see not sinking as being a plus. However, you hit something hard enough with either pod or shaft and you have big trouble. In fact easier to just pop on another pod than to repair/replace shafts and props and adjust.
7) IPS tend to produce a unpleasant rolling on the way (and this is why Volvo bought Humphree, in fact now Volvo pushes to sell IPS together with automatic intruders which balance the rolling tendency of the boat)
I didn't experience any more roll than with shafts. Most boats in the size and type we're talking about need stabilizers. Doesn't matter what type propulsion.
So why yards use more and more IPS ?
I read all you wrote in that regard. Don't give any of it much credence. The reality is yards use IPS because of handling and efficiency and most importantly, because of demand. IPS is a popular choice on certain size and types of boats. With many of these builders there was a sizable investment of time and design and testing to start using IPS.
Now, I do think some of it is marketing. The handling factor in particular when it can be achieved other ways.
With all this said, why didn't I choose IPS? One, I wasn't worried about the economy. Saving 20-30% in fuel honestly wasn't important to me. I used it because I was getting the boat for the Loop and inland rivers and Bahamas a little, but going many places and figuring there were fewer knowledgeable and expert IPS staff in boatyards where I'd be than there were with traditional staff and fewer Volvo trained mechanics than there are MAN trained mechanics. Even my engineers lack IPS experience, although they could easily be trained. Also, a very minor issue was the draft is 3" greater on the IPS. Last, the boat I was buying didn't really do a great job of utilizing the additional space gained from IPS.
I argue with a close friend all the time about my choice of shafts vs. IPS. However, the arguments you made are opinions not based on facts or real life experience or numbers. That's why AMG objects to them and that's why I do as well. No one asking you to choose IPS, but don't misrepresent it either.
You don't have to like IPS, but what you are saying about them is not really the truth. You can have both twin and triple IPS on a deep V hull, but it is an advantage if the drives are not angled too much.
I disagree with everything he has said also and I've run many pod boats well over 10,000 NM's. My sentiments and experiences mirror Olderboaters for the most part when it comes to handling and efficiency of the pods......
I also do not agree with this IPS or even the Zeus bashing. Pod drives for faster boats may have its pro and cons but from the experience I have gained with IPS boats in the family, I must say, we like them.
In the beginning I was also afraid of this "hook" under the hull but after 3 seasons with no incidents or happenings at all. The two boats in the family both are owner operated by non professional skippers (son and son in law), a 65 ft twin IPS 1200 production boat and a 82 ft quad IPS 900 one off, work flawless, perform great and are great fun for their owners. But we do not have the same problem with fauling like Florida or the Caribs.
What would we / they do different, if we would buy again in that range. The 65 was a matter of personal taste and because of its type and magnitude of use a good boat for the purpose. The next one will have Volvo Penta IPS too.
The 82 ft is a great boat but both the son and I would not buy it again. Instead of 4 x IPS 900 I would now go for tripple IPS 1200. Same ore better performance with less weight. And we would go for an production boat, the one off was far to expensive.
And this would and will be both for my sons and the humble me, a Delta 80. In our opinion the best looking and best performing 80 feeeter on the market. At first I had my reservation with tripple IPS, bcause of its steering laws and the special hull form. But watching the Delta 80 perform, this was only lack of knowledge on my side.
I am buying the point with Volvo Penta maintenance and repair in certain areas. On the US side of the pond, the Volvo service seems to be more expensive with even lower quality in certain areas. But here in Europe, the service net is very good and dense, availability of spare parts is reasonable and pricing of service and parts are not higher than any other competitor.
Larger Pods have some problems with cavitation when steering at higher speeds. But this is limited to only very few type of ships and only comes in effect at speed of 20 Kts and above. The Rolls Royce Pods of Q2 are the best example. They are the number one trouble maker on Q2.
But Volvo takes care of that cavitaion problem with speed versus angle related steering laws. And the IPS DP and Joystick modes are performing much better and more precise than the equivalent with shaft and wheel plus thrusters.
And if you get seasick on a wet lawn, dont go to sea .