Which 50' coupe with Volvo pod drives best?

If your worried about sleeping with pitch ,roll and wave slapping you better never choose a marina that docks sail boats . The song "hells bells" comes to mind, especially if you have a hangover.

I remember waking-up, when I was a lad, at 3am to see my Dad in just his undercrackers up the mast of another yacht. The rattling halyards of that yacht's rigging was driving him mad, so he clambered over the rails to tie them off for a peaceful night's sleep!

We have no problem sleeping in the 45 or in the 38 for that matter. The new hull shape on the 45 really reduces wave slap at anchor and pounding underway.

We also have a Seakeeper at anchor and Humphree auto trim underway as well so she really runs flat.

Yes, hull number 1.

Aqua, if you are seeking seaworthiness, durability and optimum handling in less than perfect sea conditions I will advise you to choose a vessel fitted with conventional shaft drives instead of the IPS drives.

Why is this?

Better and accurate boat handling at low and high speeds with a direct shaft system and a set of rudders rather than a 360 deg. rotating propeller. There are no power losses with a propeller always facing aft, but a lot of power losses when a propeller starts rotating to steer a boat. Much higher engine torque levels with the larger propellers on a direct shaft system with lower engine revolutions compared to the high engine revolutions and high propeller speed needed on an IPS system with small propellers. The transmission is inside the water on an IPS system which makes it very vulnerable in the event of a collision. Much lower revving engines with conventional shafts as opposed to very high revving engines when coupled to an IPS system in order to achieve the same cruising speed. A low revving engine is certainly a more reliable option when it comes to mechanical reliability and engine longevity. There are more advantages for a direct shaft system which I can list but these will suffice.

What you wrote is not my experience at all, and the efficiency of IPS is a lot better than shafts. If you compare a San Lorenzo 78 with MTU:s and a Delta 88 IPS, it is ten knots slower at the same rev despite more Hp..?

I agree with you. None of what T.K. wrote ties to anything I've seen. I am not a fan of IPS, choosing shafts myself, but IPS is more efficient and it handles excellently at low speed.

Is it fair to compare a lightweight carbon fiber boat with a conventional hull? I think the performance of the Delta is more a result of its design and construction than the IPS power.

The maintenance problem with an IPS boat is service and repairs if traveling outside areas with service, like inthe Bahamas or Caribbean where you ll be stuck for days while getting a tech to fly over where as just about any yard can pull a shaft and or conventional wheel.

Probably not fair to compare Delta, but I'll compare some that are fair. A 63-63' Sunseeker Manhattan. Comparison, Volvo IPS-1200 vs. Man 1000 and Man 1200. At WOT the IPS gets 32 knots the M1200 gets 31 knots and the M1000 gets 28.5 knots. So what about efficiency and economy, the M1200 uses 443 L/H vs the IPS using 306 L/H, a huge difference. To achieve 25 knots, the M1200 turns 1950 RPM and uses 300 L/H and the IPS turns just under 1967 RPM and uses 200 L/H. At 15 knots and under, their usage is virtually identical, no advantage to the IPS, but this isn't a boat designed to be run at those speeds. Low speed handling wise, I would stay the bow and stern thrusters and a joystick, you can get nearly as good a handling out of the shafts as the IPS. Certainly no better. No, this boat doesn't have a huge rudder nor do most of the boats these are installed on. We chose the MAN 1200's but it had nothing to do with efficiency, handling, or performance as those all favor the IPS slightly. It was due to using the boat on the loop and the potential of service throughout the area used as well as many of the shallow areas and the IPS boat having a 3" greater draft and we felt more potential exposure in soft grounding.

I also have demoed a Sea Ray L 590 Fly which uses Zeus and an L 650 Fly which uses shafts. Obviously not the same boat. However, the performance of the two was nearly the same and in efficiency the L590 had about a 20% advantage above 15 knots or so. Handling of the 590 with Zeus was excellent, but it also was good on the 650. What I didn't like conceptually was the limitations of Zeus due to Cummins and the fact that a 59' boat required triple Zeus 600 hp vs. the 65' with twin CAT 1150's. I would have preferred the 59' with twin conventional shafts vs. trip Zeus. However, this wasn't a negative on pods, just a negative on Zeuss pods being so limited in hp.

I have seen and talked to owners and captains of many pod driven small to medium boats, most of them IPS. I'm convinced the IPS has great handling and is more efficient. This is coming from someone who still prefers shafts, because of experience and concerns over repairs and maintenance. At the same time, if the boat I loved had IPS, I would still buy it. Many builders have matched IPS and their boats very well like Delta has done but also people like Sabre have done.

Some basic beliefs. In a boat 40-70', IPS offers an advantage in efficiency and may offer better handling. (offers better than standard shaft boats but with thrusters and joysticks and dps a shaft can come very close). I personally have concern over repairs and maintenance in some cruising locations. I also, although I prefer to have no groundings, believe IPS is more exposed to damage in soft groundings than shafts are.

I stand with what I wrote and it comes from vast experience of owning and using a variety of boats including IPS driven boats. I did not refer at all to fuel efficiency and fuel consumption. This is irrelevant to me especially in my region where fuel costs USD 0.20 per liter.

High revving engines with small IPS propellers which turn almost at twice the speed of conventional shafts are certainly not an advantage from my point of view. IPS is definitely a weaker system highly dependable on electronics, an electrical SUS servo motor and an electro/mechanical rudder brake. Too many variables can go wrong and I have seen them all.

If an owner or a skipper is seeking reliability and dependability and his objective is to tackle any weather or sea condition over long and remote distances, then I will always suggest a conventional shaft drive system over an IPS system.

Furthermore, an IPS system is very sensitive to growth and fouling. The slightest fouling of the hull or propellers prevents an IPS boat from achieving expected performance figures. This is mainly due to the very low torque values an IPS driven vessel can achieve at low rpm. It cannot easily overcome the drag and will struggle to get on the plane with a slightly fouled hull. This is not the case with a vessel fitted with conventional shafts. Due to the high torque output of the large propellers, the vessel will be able to easily overcome the friction and drag and achive planing speed quicker without the need to struggle. It is the same concept of a tractor with large rear wheels compared to a tractor with small rear wheels. The tractor with the large rear wheels will handle any terrain condition and nothing can stop if from moving forward and will overcome any condition and any terrain whereas a tractor with small rear wheels will get stuck in the slightest mud and cannot pull behind it much weight because it lacks the torque to move it forward. The IPS is the tractor with small wheels.

The Delta 88 does not gain it's efficiency from the IPS system but from the carbon fibre construction and the low weight.

I don´t know what boats you have in mind, but the IPS we have in the D88 is turning 1800 RPM at 26 knots. What figures do you have on a shaft boat? I can also add that in this season only, one of our boats has travelled more than 14.000 Nm, most of it around 30 knots, and I have not heard of any IPS problems... And I can also add that the acceleration with the "small" props is 10 seconds from idle to 25 knots...

AMG, the Delta 88 is not a benchmark or a comparison. It is achieving it's high performance figures as a result of the carbon fibre hull construction and triple 900hp engines. This is the only reason why the Delta 88 can achieve 26 knots at 1800rpm. This is not the case with any IPS vessel fitted with twin engines.

The original poster wants a 50ft boat and not an 88ft boat. Most 50ft fiberglass boats will come fitted with twin Volvo Penta D6-435 IPS600 engines. In order for this configuration to achieve a cruising speed of 23 knots the engines will turn at approx. 3100 rpm and will achieve around 30 knots at WOT and an engine rpm of 3500 rpm. The same vessel but with a shaft drive will achieve a cruising speed of 23 knots at approx. 1900 rpm and a top speed of 30 knots at WOT and at an engine rpm of 2400. I am sure you will agree to these figures.

No, I don´t agree with those figures. The reason Volvo Penta is calling their D6-435 for IPS/600 is that the IPS makes the 435 Hp engine comparable with a shaft 600 Hp engine. This difference should appear also on our carbon fibre boats.

I can guarantee you AMG, the figures I have stated above are very accurate. A Fairline Targa 48 or a Princess V48 both fitted with D6-435 IPS600 engines will achieve the following figures: 23 knots @ 3100 rpm and 30 knots at 3500 rpm. On the otherhand a Fairline Targa 47 or an older Princess V48 both fitted with D9-500hp engines and conventional shafts will achieve the following figures: 23 knots at 1900 rpm and 30 knots at 2400 rpm. An IPS boat needs to turn way higher with the smaller IPS propellers and the engines need to work much harder in order to achieve similar results of a vessel of the same size running on conventional shafts. If I were to choose between both options, I would certainly choose a 50ft boat fitted with D9-500/575 engines with conventional shafts.

The cost of a service for a D9 is the same as a D6 + IPS, that's before fuel consumption is taken into consideration.