Should I buy a boat with IPS drives?

It’s an interesting exercise to go through the data, I take away the benefits of pod propulsion are closer to 20% and not the marketing 35% numbers that you see in adds.

Keep in mind those factory Cabo test numbers could be before final prop selection but they would usually be propped light to give them enough margin, for owners equipment, Tuna towers or enclosed hard tops , higher heat and humidity conditions for Florida and tropical boats.

The aggressive maneuvering of SF boats is an admired trait in the US, not too many here concerned about it and when it comes down to it, the 800 hp MAN’s are a lot to pack into any 40’ Express or Flybridge (probably a 35’ waterline) but it’s overall performance on the water is second to none in the 40’ class when looking at speed, maneuverability and seakeeping, can’t think of another 40’ SF that I would want. Does it carry some extra hp - no doubt about it.

But keep in mind we are talking about a boat that was designed before the launch of pods and it is still a retrofit. When you specifically design for pods and get the best of both worlds you can see numbers like this 43 Spencer Express, about 30 knots at 32 gph.

https://books.google.com/books?id=s...nepage&q=spencer 43 express boat test&f=false

Interesting comparison and I just looked at some of my engine display photos. My 40 Cabo with Man R6's burns 50gph at 30knots. That is right at 1945 to 1950rpm. Looks like the Zeus package would be roughly 8 to 10 gph better. The Zeus reliability and drive maintenance is a bigger drawback IMO than the efficiency gains in real world. Especially considering there is no interior layout gain. Had this allowed Cabo to fit a mid berth bunk on the 40 Express then perhaps I would feel differently. Access in the ER with the R6 is actually pretty good.

The reduced fuel economy varies widely from boat to boat and at different speeds. I've seen data revealing a savings from 10-35%, so a wide range. I have the fuel charts on a Sunseeker Manhattan 65 with 1000 hp MAN's, 1200 hp MAN's and IPS 1200's.

It's interesting that at slow speed such as 11 knots, the 1200 MAN's and the IPS get nearly identical usage and are around 0.54 nmpg. At the same speed the 1200 MAN's get better fuel economy that the 1000's all the way up the range. For instance, the 1000's get 0.30 nmpg for 24 knots at 2150 RPM, but the 1200's achieve 24 knots at 1850 RPM and get 0.35 nmpg.

Now then comparing the 1200 MAN's to the IPS, at speed there's a big difference. To achieve 25 knots, the 1200 MAN's turn 1950 RPM and get 0.32 nmpg and the IPS turn 2000 RPM and get 0.47 nmpg. That's a savings of 32% and to achieve 30 knots, the MAN's turn 2300 RPM and get 0.27 nmpg vs. the IPS at 2200 RPM getting 0.44 nmpg, a savings of nearly 39%. In this example the IPS requires 30-35% less fuel at a normal cruise.

Our conclusion on that boat was that it was underpowered with 1000's. We did try both IPS and 1200 MAN's and decided for the loop there was just too much debris for IPS, especially since it's draft was greater than the MAN's. For all those who mention joysticks, we had joystick on our boat without having IPS.

About the heeling with IPS, as I said earlier, Volvo Penta are doing predictions, recommendations and testing of each hull they deliver to. Our boats are doing very close to "true turns" which means you can put a glass on a table and it remains there regardless of speed and radius of the turn. And this is without the use of the interceptors or gyro of course.

Good info, that puts it at about 16% - 20%, numbers that I see repeatedly especially for pods that have 600bhp or less.

Above that bhp, there is an added benefit to the hydrodynamic gains from the pod units versus the stock shaft/strut/rudder set-ups which doesn’t seem to influence as much on the lower bhp side.

Joy stick steering is not uncommon with yachts and commercial vessels to control rudders, thrusters or even all (not to mention pod drives) but with IPS it requires a steady hand and attention while cruising because IPS reacts very fast to it. Hence it being easier to steer with the wheel. For docking that joy stick can't be beat.

One key to the IPS system is proper design and setup. Response time to changes with the joystick is adjustable. I have found with the new joystick driving mode that it does take a little getting used to but then it is truly easier to steer than the wheel particularly in rough seas.

But many of the comments are correct in that the boat really needs to be designed for IPS to get the real advantages.

I also find the criticism of it's steering to be largely unjustified and somewhat a function of age and experience. If you've used a wheel for 40 or 50 years, then adapting to anything different will take some time and effort and you may never feel as comfortable. If you're a video game professional then joystick feels perfect from the outset.

I owned a Tiara 39' with IPS and took it all through the Bahamas all the time. Much of what the naysayers worried about like ripping a POD off, complexity and so on I think is unfounded. The service is indeed higher and more expensive and I treated the PODS like glass.
Real world fuel consumption was about 20-30% better but in my experience there is a big BUT. The engines for like performance have lower torque so in rough seas they tend to labor more. Said another way, your mileage will vary based on conditions.

PODS are great for getting people into boating and they've developed them dramatically since mine.

There seems to be a big difference between this side of the pond (Europe) and the US, especially the south east coast of the USA, as far as Volvo Penta IPS is concerned. The VP service network, the qualification of their (?) service personnel and the availabity of spare parts appear to be much worse than in Europe.

From what I read on YF about IPS boats and its problems with the pod drives, I would not buy a boat with Volvo IPS for example in FL.

The IPS system needs a specific hull design for the pod drives. A boat with a hull designed for shaft and wheel / rudder will not perform perfectly and far less efficient with IPS.

We have two IPS boats in the family. My son in law (a medical doctor, definately not a professional boater) and my oldest daughter own a Prestige 680 with twin IPS 1200 and my oldest son owns a 80+ft Dutch custom built quad IPS boat. Both hulls are designed for IPS only. The Prestige 680 lives on the Weser river above the first lock in sweet water but is operated mostly in the North Sea. The 80+ ft Quad IPS lived the first two seasons in the Baltic Sea but has been relocated as deck load to the Med last year.

Other than regular maintenance and anual inspections (out of the water), they have not seen any Volvo mechanic. The Prestige 680 gets about 250 hours per season and the quad IPS a little bit more, may be 400 hours. Volvo Penta service in Europe is great, there is always a service station in reach and the mechanics are well trained. Prices are a little bit higher than a VW car shop but still reasonable. Both boats are owner operated without crew. Only cleaning and cosmetics are done by local contractors.

Both boats are on market now. The Prestige 680 will be traded in for a new 680 with a different interior and twin IPS 1350 and the quad IPS will be exchanged with something bigger with surface drives. My son wants to see 40 Kts, which IPS cannot deliver.

As BoulderGT3 said, IPS pods are great for getting people into boating. And Volvo Penta has definately a problem in the US. But the same seems to be valid for high speed MAN engines in the US. And when reading the numbers posted on YF for service, repair and parts / haul out in the US, I must say, You guys are being ripped off. The only thing which is much more expensive in Europe is fuel. At the moment about 5 US $ per gallon for EN 590 diesel.
But most German North Sea boaters refuel at the tax and VAT free Island of Helgoland anyhow.

What’s is the maintenance and other trade offs between surface drive and pods?

My son is very happy with his quad IPS setup. He only wants more speed which the Volvo IPS pods are just not build for. Around 35 Kts seems to be their limit. As far as handling at all speeds, close quarter maneuvering, docking, efficiency and comfort of ride, IMHO nothing can beat IPS in that size, as long as You have a boat that was designed for that system from the beginning and is equipped with interceptor stabis additional.

For higher speeds, if You do not want conventional shaft and prop, You have only the choice between surface drives and Water jets. Waterjets are awfully inefficient at low speed but work nicely at their design speed. And low speed maneuvering and backing into a slip is no real fun either. With surface drives, You will get most likely the highest speed for a given engine package, depending on the type of surface drives You are choosing.

My son and I have tested some speed boats in the 80 to 100 ft class with waterjets and Arneson surface drives a few years ago. Also he got addicted to those nice Rooster tails at speed, he bought the quad IPS, as strongly requested by his wife . She was afraid of that wave pattern and that roaring noise.

But now he wants to go bigger and faster. With quad IPS 1350, the size limit would be at around 120 to 130 ft and still with max. 35 Kts. Lars Modin has some very nice designs in his portfolio at 105 and 130 ft. I personally think, 35 Kts are more than enough, especially with all the advantages You gain with IPS. I am still trying to talk him into one of those.




We do not prefer the Arneson drives. My son has some jetty neighbours in the Med with Arneson drives (Pershing). They are either not used at all or have a lot of trouble with their propulsion train. But with 4 non steerable surface drives like the Levi drives or the Q-SPD drives, the props ventilated with the exhaust gasses, one could go up to 165 ft LoA. With quad MTU 16V2000 M96L and 4 Q-SPD drives even a Mangusta 165 E could easily make 40 Kts cruise.






These are pictures of smaller variants but bigger ones are available on request for up to 3.000 HP each. I am sure those drives are far less trouble prone, cause less maintenance and are even cheaper to buy than Arneson drives.

With the Corona travel restrictions, I have most likely some more weeks to convince him. I would like to hear the opinion of Lars about IPS in general and especially about a larger IPS boat with quad IPS 1350 versus
one with surface drives, versus conventionell shaft and wheel.

HTMO

Hello my friend,

First, with IPS/1350 they have props for speeds up to 42 knots. With the D8/800 the limit is 40 knots and with the D6 range up to IPS/650 you today have props for speeds up to 50 knots!

The 105' boat with quad 1350 was intended to be built in carbon fiber as our other large boats and with the same approximate performance of top speed near 40 knots and cruising 30+.

At the same time as I did this design, Volvo Penta presented a hybrid solution, with integrated electric motors, why the project was waiting for more info. Since then this hybrid has vanished from their map and we don´t know if it ever will be launched or be replaced with a new concept. Whatever, a semi electric drive would be the perfect combination for the IPS drives. Especially compared to water jets or surface drives.

Conventional shafts are of course a good solution on displacement and semi displacement yachts, but not that efficient compared to IPS between 20 and 30 knots cruising speed. As always the decision must include your personal preferences on speed, vs range and cost...

Hello Lars,

Great info Lars. My Volvo IPS knowledge seems to be not up to date then. Your connection to the Volvo guys is definately much better than ours as normal mortal end users. When talking to VP Germany in Kiel, they only told us to talk to the boat manufacturer for more details.

I will tell my son in law about the higher speed props for his new Prestige 680. His dealer did not say anything about them. He probably did not know either.

The 105 quad IPS is a perfect design Lars. Will Delta Power Boats still build it?

What kind of propulsion did You plan for the 130?

HTMO

The 130 was intended for pods or shafts, but just semi displacement with cruising about 12-14 knots, a floating beach house.

The 105 could be built by Delta Powerboats if we could sell a few before making moulds, but we are not actively marketing it now.

Instead we are making moulds for a big catamaran that can be ordered in different lengths, from about 24 up to 40 meters with the same beam of 13,6 meters. The first built should have IPS...

/L

Our boats are infused with divinycell core and an average sound level from our measuring is around 7o db(A) in all planing speeds. Like in a modern car, you talk without raising your voice.