[CaptEvan]

I have had the privilege of covering nearly 5,000 miles on Tiara's 5800, with triple IPS 600's. The experience has shown the following:

1.) The fuel economy gain is very real. Cruising at 28 knots fully loaded to over 50,000 lbs. displacement she burns 50 gph.

2.) The best fuel economy is spread over a wide rpm range, 2,600 to 3,200.

3.) With any engine shut down, she will get on plane and run 22 knots at WOT or 18 knot cruise, however, the 2 engines are running extremely overloaded and consume 6 gph more than if running all 3 engines at the same speed.

4.) The boat stays on plane down to 14 knots, but that speed is not very efficient.

5.) I am now beyond calling the use of a joystick cheating, as docking in a stiff breeze can make you a hero. The joystick maneuvering is an easily learned skill, easier if you never used bow or stern thrusters and tend to ask for all or nothing. The longer the vessel in a beam breeze, the more you need to keep your bow with you with a twist of the stick.

6.) The steering response is extreme, like running a 60' ski boat. In evidence, try to track a waypoint you've already passed.

7.) A failed steering unit can be manually set straight to get home.

8.) Holeshots to plane are impressive due to superchargers carrying you to the turbos.

And thankfully I cannot report what happens when the drives are slammed into concrete,

Evan

[denizci]

Thanks guys, especially CaptEvan, for sharing your IPS experiences. So far, it's clear to me that IPS pod drives are superior to the conventional shaft drives. There are more boats are buing build with this new system. Also, whenever you have a chance, please check Sept 08 PMY magazine pages 81-86. There is an excellent article on IPS triple config. You will realize that the necessary space required is so little. Based on the pictures I have seen and other specs I have gathered, a very wide beam is not necessary to be able to have quad engines; a 171 inch beam can do it (this info was not in the article, it came directly from Volvo Penta engineers) There are already plenty of boats out there which can accomodate quads in terms of necessary beam width... I guess it's matter of time to see these boats with quad IPSs on the market...

Regarding electric or hybrid engines, there are two car companies made some interesting advances which I believe boat manufacturers should keep close eye on:
- A California firm called Tesla Motors came up with pure electric vehicle with 185 kW engine (I believe it translates to over 200 hp). And the rotor (electric motor) weighs only 115 lbs and a size of an watermelon. Of course this excludes the battery and the transmission..

- Lexus has come up with a hybrid engine 200+ hp gas and 200+ hp electric. They are experimenting it with their race cars and results are positive.

All these developments are prompting me to see this kind of products with marine vessels. I am simply dreaming about very efficient and yet powerful hybrid engine coupled with IPS drives. So I can cover many thousand nms without refueling on a low speed or drive over 40+ knots if and when I want to...

[Skiffy]

I get the strong impression that some are backing away from IPS slightly and at least two major builders are not considering them for the next two or three years production at all.
In my work I talk to builders specifically about drive options.

[AMG]

Originally Posted by Skiffy

I get the strong impression that some are backing away from IPS slightly and at least two major builders are not considering them for the next two or three years production at all.
In my work I talk to builders specifically about drive options.

Hi Skiffy, when you say backing away, it means that they have used them and didn´t like them? After spending yesterday at the IPS test center, driving both existing and coming versions, I found that docking was almost too easy. They told us that customers usually found that the whole family now could drive and dock their boat, sometimes the wife and kids better than the husband...

Compared to shafts and rudders it improves on speed and range, liberates living space inside and the joystick makes the handling safe and easy.

They said that even conservative sport-fishers are now starting to use them since they are so easy to handle when fishing.

I have not yet seen a Zeus drive in real life, but since you have to make a special hull for them, they are probably facing more problems with boat builders than IPS and the only other drive system that comes near in handling, is waterjets which have other limitations.

I am pretty sure that pod drives with joystick steering is what the clients will ask for in boats from about 40 feet and up. Below this the stern drives are still better for most inboard engine boats.

[Skiffy]

That's what I'm seeing from builders.

I agree they are fantastic systems and the manouvreability is a great incentive to new owners, really easy to park. The joystick is a great development as close quarters control has always been very stressful for owners and the family and friends aboard, it's the bit most people hate. It will be what lots of people want and they will be pushing builders to offer the system on a bigger range of boats. But there is a bigger group of builders and users that see this as complex and high risk in terms of maintenance and reliability.

They will grow in popularity but I'm getting the impression many builders will now go in a different direction.

It has made builders sit up and think with regards to propulsion systems and efficiency though, which is great for hull designers and end users.

[NYCAP123]

That sounds a bit like you may be trying to wag the dog. The only thing I hear is excitement over IPS. I don't think orders for IPS are slowing down so much as orders for boats and subsequently IPS and everything else.

[Skiffy]

Not wanting to upset the forums non commercialism, but we will get a one sided view, as builders who come to us are looking for alternatives. I'm more likely to hear the problems than the praises of other systems. But that's what is great about forums you'll hear from a range of people with a range of knowledge or industry experience.

[CODOG]

Things will get more interesting when the higher powered versions are commercially available. The smaller boat sector can be argued to be suffering most from the current financial climate, yet the current crop of engine and drive packages suit the smaller boats best. Unless you have a hull form that allows multiple engines abreast (either a totally new hull design developed around the drive system and all its hydrodynamic quirks, or an existing one that can be modified to a point where the drive system can work with the hull design and not against it) then the overall size / construction / fit-out will be limited.
As always, power to weight is paramount...some builders will struggle to balance what has become their accepted fit-out and construction standards and materials with the overall weight restrictions dictated by current drive packages, and yet still be as attractive and acceptable a package to their established customer base...come the larger powered engine and drive packages, the market will shift quicker.
There is a strong argument for brand new hull designs that are tailored specifically to get the most out of these drive systems....the offset to this is that these new hull designs will no longer have the optimised form to suit other drive systems such as stern drive, shaft or surface drives. This will need a lot of thought from series production builders as to which way their resources and ultimately volume of product should be directed.
Zeus and IPS work in different ways, each putting different steering / directional and heeling stability / longitudinal trim demands through a given hull design to be able to make the most of their respective handling / efficiency promises. A universal hull design that works fairly well with all of these new and more established drive systems will compromise the running and handling for each to some degree.
As such, a builders decision to go with one or the other of these new systems is rather involved. Once the higher powered options are available, larger market sectors open up and for those builders that produce a wider range of sizes and types, that decision may be easier.

[NYCAP123]

"the offset to this is that these new hull designs will no longer have the optimised form to suit other drive systems such as stern drive, shaft or surface drives."

That's a very interesting point. I see no problem for the coustom sector, but what of the Sea Rays, etc. Will they start setting up 2 or 3 molds for each model or throw all their chips in on one or the other? On top of this financial crisis this sounds like a lot of risk. These drive systems could end up like jets and surface-piercing; decades later still trying to find a way into the mass market.

[Capt J]

Originally Posted by NYCAP123

"the offset to this is that these new hull designs will no longer have the optimised form to suit other drive systems such as stern drive, shaft or surface drives."
That's a very interesting point. I see no problem for the coustom sector, but what of the Sea Rays, etc. Will they start setting up 2 or 3 molds for each model or throw all their chips in on one or the other? On top of this financial crisis this sounds like a lot of risk. These drive systems could end up like jets and surface-piercing; decades later still trying to find a way into the mass market.

I know that Searay offers the 48' Searay with Zues drives and Cabo has a 40' Zues drives. Both have great fuel economy in comparison to traditional diesels. Check out this test on the 40' Cabo with Mans, Cat, and Zues including speed, fuel burn etc. Although the CATS with traditional drives have a better range at near cruise speed (1800rpm's), they seem to be better then the MANS across the board
http://www.caboyachts.com/yachts/40X/INDEX.ASP

What I have heard is that Brunswick is offering/ or let's say venturing in to create one hull size in each brand that they feel is BEST suited for the zues drives. Yet, with the economy and so forth they will not take any deeper plunge then that at this time. This is only what I heard through the grape vine. Which makes sense, they may be underkill or overkill for other hull types or sizes and not perform as well.

I personally at this time would be leary of convincing an owner to buy a boat with them. They have a lot of pluses and no negatives that I really know of. However, I feel the current buyers are going to be the long term gunea pigs of them. They have a lot of electronics and components, and I would like to see the longterm durability and maintanence costs of those components because they're not cheap.

[CODOG]

An improvement in propulsive efficiency has to be a good thing, gains in fuel economy, same speed for less power etc. Trouble is, these gains are subject to a suitable hull form, suitable running trim, suitable heeling characteristics in a turn etc. IPS and Zeus differ in what they want a hull design to do. One of them is easier to get to work well in a typical deep-v hull designed originally for higher speeds, both can work well with flatter, shallower deadrise and less inherent high speed stability. Taking composite hulls from out of a mould...Both can be incorporated into existing hull designs by implanting the mould accordingly and shifting the final build LCG. This is the rub...existing hull designs / moulds were not designed for these drive systems. Whilst there are several successful boats running around with these drives now, the best must be boats developed around the drive system rather than a happy out-come to a 'fit it and see what happens' experiment...the science is relatively new, with very small numbers of case histories (and hence real-world design experience). As mentioned before, once larger powered versions are available, the impetus may accelerate.
If only stern-drives were available that could throw larger props and take bigger power and torque...similar increase in propulsive efficiency, but with the added bonus of trimmable thrust...they would take some of the compromise out of the equation when trying to make existing hull designs and LCG layouts work well.
I still advocate a hull design and package displacement specific to the new-age drive system and associated hydrodynamics is the best way to market boats with these sytems. Some builders can and will, some cant and wont.
Ironic that a system to improve the efficiency and economy of pleasure boats may prove to be uneconomic to develop and incorporate in todays market. Increasing the range of sizes and hence the range of suitable installations will obviously spread the bets and reduce the risk commercially. Big question short term is will the market still be there when the product hits the shelves.

[rampage38]

Did anyone notice that Viking announced a 42' convertible and express with IPS drives? They say that it is a boat for "hazy economic times."

http://www.vikingyachts.com/models/p...p?numIdVal=42C

[AMG]

I am in the middle of this now, started to develop a 54´hull for the IPS II (pictured), but found out that the added size and weight of the IPS/900 will be negative for the outcome and I am now back to using the IPS/600 as double or triple installations.

This hull will be purpose built for the smaller IPS and since none of the IPS drives have props for more than 45 knots, this will be the top speed anyway.

I agree that more power to stern-drives would be better, but the joy of joystick handling is not there yet and I don´t think they will work as smooth as with IPS.

[CODOG]

I can envisage a purpose designed hull with triple IPS set up being rather amazing Lars. Puts a different slant on things power to weight wise.

[AMG]

Originally Posted by CODOG

I can envisage a purpose designed hull with triple IPS set up being rather amazing Lars. Puts a different slant on things power to weight wise.

Yes, it will be a 25% weight saving and the flexibility of using two or three. Plus the hull can be with more bouyancy with smaller drives. We are building very light and today many of our competitors are using 50 % more fuel, going 10 knots slower. Hoping to achieve similar results with this one..