POD Drives

[capttonyf]

Opinions on POD Drives compared to Inboards. I'm an Inboard guy probably because it's what I know,,,, BUT. Is one design better then the other, or do they each have an equal amount of Pros and Cons to where it becomes a matter of preference? I would think the pros and cons between the two are similar to the pros and cons between an Inboard and say a Mercruiser I/O.

For years people didn't keep I/O designs in Saltwater because of corrosion and all the moving parts and gears. Even though an I/O is more responsive with more trim capabilities it wasn't worth the Maintenance trade off when compared with an inboard.

That being said with a POD you have Joystick docking, GPS Position holding, great efficiency, and making a "NEW" boater more confident at the dock where it becomes as simple as playing a video game, Correct??? Or am I wrong? I've only ran one and it's nice for a new boater but for a guy who can run dock an inboard boat, I prefer inboard, for these reasons below.

1. If I lose steering I can use the throttles to steer me home.
2. If, If I would hit something and rip running gear from the boat would the hole be smaller?
3. Maintenance, No moving parts under the boat. Plus I would assume a Shaft is Cheaper then having to replace a POD if corrosion does happen.
4. Simple, it's what I know and am comfortable with.

These are assumptions, if anyone knows the facts I'd appreciate it. One of the Motoryachts my client is considering has ZF PODs and I don't want to give him my Blessing with out more knowledge on the subject.

I see all the Benefits of POD's just as I see the benefits of I/O's, but I wouldn't want a 35 ft offshore boat with I/O's I'd want Inboards, are POD's the same. I'm just wondering if their are more things to worry about with them then a conventional Inboard Boat.

Last thing, can a POD Boat be steered home like an inboard boat if the steering does go out?

Any insight would be Greatly Appreciated.

Thanks

Tony

 

[TopHattandTails]

Having maintained a pod boat for 4 years, I have a little insight. First, pods offer a big advantage over shafts for docking and close quarters maneuvering. Even better than a shaft boat with a bow thruster. They are fuel efficient. But that's about where my appreciation ends. The do require quite a bit more maintenance. To answer your q's - it all depends. Depends on the pod mfg, version, etc. my experience is with Volvo penta 1.0. This is a the smallest of the pods. This particular pod system is also outfitted with the "sport fish" option - which isn't found on any other version 1.0's in captivity, except for this manufacturer (Spencer). You would need to go to the 2.0 or 3.0 for that on other volvo's. The main gasket on the lower unit on the 1.0 is a typical replacement (oil leak). Not so on the 2.0 or 3.0. I have zero experience with the ZF' s so - you gotta ask.
1) sport fish mode allows single shifter/ torquey drive to turn and back down on fish. So it could be used to drive without stearing real easy.
2) the force that you would have to hit something to pull a pod off would be earth shattering. Assuming everyone was able to walk after that, the design is supposed to release the lower unit with no water in the boat. A shaft boat would have a hole where the shaft was removed from the tranny. In my opinion - this is not a valid concern but always comes up.
3) shaft is way less expensive to maintain. Again- will be model/ make specific. Ask the maintenance guys, not the dealers. Ask if you can change the lower unit oil with the boat in the water
4) there is a short learning curve with the different modes. But if you can handle trolling valves on a shaft boat - pods are no more difficult.

 

[capttonyf]

Having maintained a pod boat for 4 years, I have a little insight. First, pods offer a big advantage over shafts for docking and close quarters maneuvering. Even better than a shaft boat with a bow thruster. They are fuel efficient. But that's about where my appreciation ends. The do require quite a bit more maintenance. To answer your q's - it all depends. Depends on the pod mfg, version, etc. my experience is with Volvo penta 1.0. This is a the smallest of the pods. This particular pod system is also outfitted with the "sport fish" option - which isn't found on any other version 1.0's in captivity, except for this manufacturer (Spencer). You would need to go to the 2.0 or 3.0 for that on other volvo's. The main gasket on the lower unit on the 1.0 is a typical replacement (oil leak). Not so on the 2.0 or 3.0. I have zero experience with the ZF' s so - you gotta ask.
1) sport fish mode allows single shifter/ torquey drive to turn and back down on fish. So it could be used to drive without stearing real easy.
2) the force that you would have to hit something to pull a pod off would be earth shattering. Assuming everyone was able to walk after that, the design is supposed to release the lower unit with no water in the boat. A shaft boat would have a hole where the shaft was removed from the tranny. In my opinion - this is not a valid concern but always comes up.
3) shaft is way less expensive to maintain. Again- will be model/ make specific. Ask the maintenance guys, not the dealers. Ask if you can change the lower unit oil with the boat in the water
4) there is a short learning curve with the different modes. But if you can handle trolling valves on a shaft boat - pods are no more difficult.

Thanks for the reply, my biggest concern I think lies with maintenance and the fact I'm a creature of habit and fully understand how a shaft drive boat works compared to not knowing on a pod boat.

One question if you lock the steering straight on a pod boat and dock it the way you would dock an inboard boat does that work as well? I was thinking it would probably react similar to docking an I/O boat with the wheel straight which is not as good. I've heard mixed reviews similar to what you've mentioned. Change is good, "Sometimes", it's just I'm cautious about it when it invovles so much $$$$$.

Again Thanks

Tony

 

[Pascal]

I think it is a bit unfair to compare pods with stern drives as the construction, alloys etc is far better

Indeed pods are supposed to shear clean if you strike something so in theory there will be a lot less damage

Initially when Volvo launched IPS they claimed over 30% improvement in fuel burn but initial tests showed it was a lot less and not enough to offset the higher costs. With time builders have optimized hulls for pods and fuel efficiency must have improved

one issue is where will the boat be used. If you don't stray too far from a dealer then fine but if your plans in includes areas like the bahamas or places without dealership support any failure will be very costly as you will have to pay travel expenses. On the other hand any yard can swap a shaft, wheels, repair rudders.

 

[capttonyf]

I think it is a bit unfair to compare pods with stern drives as the construction, alloys etc is far better

Indeed pods are supposed to shear clean if you strike something so in theory there will be a lot less damage

Initially when Volvo launched IPS they claimed over 30% improvement in fuel burn but initial tests showed it was a lot less and not enough to offset the higher costs. With time builders have optimized hulls for pods and fuel efficiency must have improved

one issue is where will the boat be used. If you don't stray too far from a dealer then fine but if your plans in includes areas like the bahamas or places without dealership support any failure will be very costly as you will have to pay travel expenses. On the other hand any yard can swap a shaft, wheels, repair rudders.

The boat will be used in FL, Bahamas, and the FL Keys primarily. They did mention they may want to try to take it to the NE one summer but I'm pretty sure it will be a Bermuda Triangle Boat.

Tony

 

[Tim Powell]

The boat will be used in FL, Bahamas, and the FL Keys primarily. They did mention they may want to try to take it to the NE one summer but I'm pretty sure it will be a Bermuda Triangle Boat.

Tony

My problem would be if something goes bad it being in the triangle would be capable mariners. I have riden in one only once Fast but it was in a sport fish wooden boat 48 feet long, The thing will go sideways.

 

[spindrift]

Tony

I would take a few minutes and try to get ahold of Bruce Johnson who used to be head designer and President of Sparkman and Stephens. Bruce now works for 3 very good yards up on Maine (Lockport Marine, Brooklin Boat Yard, and Front Street Shipyard). Bruce has actually done a recent custom design
which I think was built at Rockport. He told me the Volvo people were very professional to work with.
For the size of the power plant Bruce claims they attained some incredible speeds and high fuel efficiency. That being said, the real win with the system was docking an maneuvering in close quarters.

One drawback that I have heard from the people at Hargrave is that Pods are not good choice are larger boats (70 feet plus) due to gearing issues required with heavier vessels. It does not sound like your client is in that larger size bracket.

If you want to speak with Bruce let me know and I will forward his cell phone to you.
He is extremely knowledgable about design and systems. I am hoping to let him loose this year on
two new design/ builds for me as the cash flow allows.

Cheers
Dennis

 

[Andy B]

I knew three boats with pod drives, after a couple years they became maintance nightmares. Seals leaking on the gear case leting seawater in. I think the overhaul cost was around 20k. All the owners have sold the boats. On tangle with a crab trap line and it was off to the boat yard.

 

[egaito]

I had to pull a pod boat off the rocks a few years ago, and I can confirm that they don't leak when sheared off. One drive came completely off the boat, the other broke a shear pin, leaving the boat with no propulsion, but it didn't come all the way off.

The upside was the drive landed in about 5' of water, was recovered, repaired and remounted. The downside was that at the time, there were few people qualified to work on them. Someone had to be flown in (to Georgia) to do the repairs.