Pod drives for large yachts

Captain J/Older, it is good to get feedback from people who have run these systems over a lot of miles. It is also interesting to hear different view points, but facts do matter.

When I was on merchant ships years ago we were burning oil, to heat water, to make steam, to turn a turbine. Technology is a good thing.

Well, there are many pods and some have long been used in large boats. As to IPS there are incidents of them fitted into 80-100' MY's with three or four units installed.

I am a bit surprised about your comment regarding maintenance headaches with Arneson Drives ... can you expand on that? What headaches have you experienced?

I owned a boat with IPS500's. I didn't see the real world fuel savings being discussed above. In rougher water they didn't have the torque of straight shafts and were much more in and out of the boost. Fuel savings were maybe 10-20% in what I call actual conditions. Lower vibration, low bow rise and quiet. I would buy another pair for the way I use a boat but I think they are great for some people.

We did 500 hours on a Sabre with IPS and not only got the expected increase in fuel mileage but also had no issues on multiple trips to the Bahamas and many other cruises. In fact, we have a new Sabre on order with IPS and expect similar results.
The maintenance costs are a little higher but if you use the boat, you have can offset some of that cost with the fuel savings.

We also have two friends who managed to drive their boats aground at speeds exceeding 20 knots. Both lost a pod but had NO water intrusion at all. Other people we know who did that same with shafts had a more serious issue with water into the boat.

The quiet operation and underwater exhaust make a boat with these drives much more pleasant to use.

I worked for a guy who had a set on a Magnum 56. They gave a lot of problems with seals and the circlip that retained the thrust bearing getting popped out

A little thread drift regarding the Arneson drives...There is a sunseeker at our marina that has them. I often stop and check out the props and marvel at their design. They remind me of a sub prop. I have heard on a different forum that at lower speeds a boat with these can be difficult to handle? They guy who runs this particular boat seems to have no issues coming down a narrow fairway.

Interesting. The guy who drives that Sunseeker drives in reverse several hundred feet, in a gap of about 75 ft. He then goes stern in, to a side tie, with a sea wall about 15 ft. away, and on low tide some very skinny water between the boat and that wall. I always thought he did a nice job parking, and now I have even more appreciation for it.

As far as I can see there are no pods available for the +/- 2000hp motor market correct me if I'm wrong , hence large sport fishers and the like have to have multiple pods i.e. 3 or 4 which negates the fuel savings and in fact just adds to the coats of running with maintenance etc.
Some of the yachts are running 45+ knots on shafts , yet it seems all pod IPS Zeus and even ZF claim only 37 knots top speed irrespective of multiple pods is this prop design or manufacturing limiters?
Perhaps this is why custom fishing boats builders are very slow to take the idea up.

The Wajer Osprey 38 is reported to do 45 knots at WOT with twin IPS 600

Yup my point exactly 38 foot the moment you get over 60 feet the problem starts

The problem being the pleasure boat market in that size range just isn't a big enough market to warrant large expenditure and risk in the design and development of a small pod to deal with that part of the market.

There are plenty of options for pods when you get bigger

German company, Reintjes make a fixed pod with fore and aft props that can handle up to 2,600 HP.

Rolls Royce too has entered the 2000hp market for smaller yachts.

https://www.rolls-royce.com/product...rs/azipull-carbon.aspx#section-product-search