Conventional or POD Drives?

Marin · Jan 10, 2011

I see no reason why pod drives shouldn't enjoy the same reliability over time as conventional drives. They will most likely require some different types of maintenance to a conventional drive, but I see no reason to believe they will be more costly in the overall scheme of things than conventional drives. How many posts do we see about conventional drive systems where they "make a funny rumbling," "the shaft vibrates," "the shaft logs leak too much, " and on and on and on. I don't think pod drives will be any different and by eliminating the long drive shafts and supporting structures and bearings and rudders they actually may require less maintenance and repair.

In my opinion, the comparison between pod drives (well designed and well built) to the drive systems in our boats today is like comparing a Mercedes to a guy rolling a hoop down the road with a stick

RickB · Jan 10, 2011

Pod drives

Jon · Jan 10, 2011

Marin,
I think, in my opinion, the comparison between pod drives, to the drive systems in our boats, that would be used on the Loop and the Bahamas ( with the fun of gunk holing and occasional groundings) is like comparing a Lamborghini with a (slightly dented) Toyota Landcruiser
Jon

JohnP · Jan 10, 2011

Jon wrote:

Marin,
I think, in my opinion, the comparison between pod drives, to the drive systems in our boats, that would be used on the Loop and the Bahamas ( with the fun of gunk holing and occasional groundings) is like comparing a Lamborghini with a (slightly dented) Toyota Landcruiser
Jon

Yeah, I would not go quite as far as Marin, on the hoop and stick thing!

*

Marin · Jan 10, 2011

RickB wrote:

Pod drives

Rolls can't seem to get anything right these days......

*

Marin · Jan 10, 2011

Jon wrote:

Marin,
I think, in my opinion, the comparison between pod drives, to the drive systems in our boats, that would be used on the Loop and the Bahamas ( with the fun of gunk holing and occasional groundings) is like comparing a Lamborghini with a (slightly dented) Toyota Landcruiser
Jon

I don't agree with that at all.* There is no reason a twin-engine pod-drive boat can't be designed to provide the same degree of protection to the drive system as converntional twin-engine boats have--- in other words, a keel or some other component to hit first.* Running a conventional shaft, struts, prop and rudder into the bottom is going to leave you every bit a screwed as hitting the bottom with a pod drive.

I'll go along with the notion that a single engine boat with its prop and rudder behind the keel could be less vulnerable to a soft grounding than a twin engine anything (other than a jet boat).

But I've always maintained that running aground is totally a function of a dumba*s driver and not an automatic consequence of the boat's hvaeing one, two, or ten engines or having shafts, props, and rudders or* I/O drives or pod drives.* But maybe I'm wrong......

-- Edited by Marin on Monday 10th of January 2011 03:07:32 PM

Nomad Willy · Jan 10, 2011

Well** ...if the builder would take the trouble to remove the center keel and install two keels along the propeller shafts of the twin the twin would have as much protection as the single. Furthermore the twin keeled craft would not lay over on her side when high and dry. Then w hydraulic thrusters fore and aft, plus the twin screws the pods would be cost effective.

Jon · Jan 10, 2011

Marin,
I guess I'm one of them dumb a?s drivers who ain't happy unless they're trying to get off the beaten track,and boldly go where no dumb a?s has ever gone before!
I couldn't imagine cruising if I thought a slow speed grounding was going to end the cruise - that's why we have tide tables,kedge anchors and shovels.
Jon

Moonstruck · Jan 10, 2011

The question was, " would the pod drive break off at a 20 knot soft grounding".* I am not defending any system.* Just trying to figure out what I would buy in the future.* I was surprised that there was so little damage done at that speed.

Grounding is a real problem as most of the areas south of the Chesapeake* have allot of shallow water around.* Fortunately, most of it is soft bottom.* Much of the ICW runs behind inlets that make the channel subject to shoaling.* Our bottoms shift with the currents and storms.*Soft groundings are commonplace.* I just want to know what happens.

-- Edited by Moonstruck on Monday 10th of January 2011 03:28:19 PM

BaltimoreLurker · Jan 10, 2011

nomadwilly wrote:

Well** ...if the builder would take the trouble to remove the center keel and install two keels along the propeller shafts of the twin the twin would have as much protection as the single.

Wouldn't that negate much of the efficiencies realized by having the pod props out in clear water?

*

Marin · Jan 10, 2011

Moonstruck wrote:Grounding is a real problem as most of the areas south of the Chesapeake* have allot of shallow water around.* Fortunately, most of it is soft bottom.*

Well, people relate things to their own surroundings.* I'm not sure if I regard running gently into a mud bank even as a "grounding."* Out here, a grounding generally involves a major, very expensive repair because what you hit is generally a rock or a rock ledge or reef.* Not much in the way of shallow mud banks around here.* You're either floating or you're on the rocks at a 45-degree angle when the tide goes out from under your boat.

*

Moonstruck · Jan 10, 2011

Marin wrote:

Well, people relate things to their own surroundings.* I'm not sure if I regard running gently into a mud bank even as a "grounding."* Out here, a grounding generally involves a major, very expensive repair because what you hit is generally a rock or a rock ledge or reef.* Not much in the way of shallow mud banks around here.* You're either floating or you're on the rocks at a 45-degree angle when the tide goes out from under your boat.

*

It is true that the*farther north there is much solid rock that can cause severe damage.* The good thing about that is that it takes an earth quake to move it.* With the shifting bottoms that we have, I have seen boats aground between a red and green marker.* Dredging channels is a reality.* There is alot of coral rock in the Bahamas and some in the Keys.* There is some on the OWW.* For the most part it is soft.

When you hit anything at 20 knots, it is not gentle.* Usually something has to give.* I just want to know what that is on a pod drive.* Some times it can mean bent running gear and damaged transmissions on a conventional drive.

*

JD · Jan 10, 2011

Moonstruck wrote:The question was, " would the pod drive break off at a 20 knot soft grounding".* I am not defending any system.* Just trying to figure out what I would buy in the future.* I was surprised that there was so little damage done at that speed.

Grounding is a real problem as most of the areas south of the Chesapeake* have allot of shallow water around.* Fortunately, most of it is soft bottom.* Much of the ICW runs behind inlets that make the channel subject to shoaling.* Our bottoms shift with the currents and storms.*Soft groundings are commonplace.* I just want to know what happens.

-- Edited by Moonstruck on Monday 10th of January 2011 03:28:19 PM

My thought is that the Pods are no more exposed than Stabilizers.* Yes they do get taken off but it isn't an everyday problem.* Maybe we need to take our heads out and keep a better watch.* Well at least if we have Pods.

*

JohnP · Jan 10, 2011

One thing good about an old slow boat is you cannot run aground at 20knots. The few times I have read about such accidents they have resulted serious injuries to the crew. Accidents happen when they are least expected and people can be thrown about with bad results.* Boat damage seems unimportant when people are hurt or worse.* I am pretty sure pod systems are built to take soft groundings at low speed. Don't know if they test them to destruction.*

Take care be safe.

Moonstruck · Jan 10, 2011

To me the most desirable drive would be a single screw protected by a keel and skeg.* Krogen and Nordhavn and porbably others protect their twin screw running gear with skegs.* Seems like a good solution to me.

With bow and stern thrusters available it seems to me that adding computers to control the boat is just complicating the mix.* I'm kind of in Eric's camp on simpler is better.

Moonstruck · Jan 10, 2011

JD wrote:

* Maybe we need to take our heads out and keep a better watch.* Well at least if we have Pods.

*

JD, I think that you are in NC.* Watch it at the Alligator River entrance,*in Bogue Sound, both channels going into Beaufort, behind Bogue Inlet, at the White Oak River junction at Swansboro, behind Bear Inlet, New River crossing,*behind Carolina Beach, and Snow's Cut just to name a few.* You don't have to be out of the marked channel to run aground.* That is just one section of the ICW.* Those Tow Boat/US and Seatow boats don't hang around for nothing.

I subscribe to the theory that those that cruise the ICW and haven't run aground probably will.* I operate my boat accordingly.* My charts are full of notes.* The above was from memory.* The charts are on the boat.

*

Marin · Jan 10, 2011

Moonstruck wrote:

With bow and stern thrusters available it seems to me that adding computers to control the boat is just complicating the mix.* I'm kind of in Eric's camp on simpler is better.

Simpler is better unless you are going for efficiency, flexibility, and capability.* You can do things with pod drives you cannot even come close to with conventional drives.* You can do things with power boats you cannot come close to doing with a rowboat even though a rowboat is a lot simpler than a powerboat.

So it all boils down to what you want to accomplish. Simple accomlishes simple things, complex accomplishes complex things. My wife would like to be able to park our boat in any slip, on any dock, in any wind, in any current with a single stick or better yet, a couple of pushbuttons.* She doesn't want to jockey throttles and shifters and rudders because she's not interested in that stuff.* She loves boating and driving the boat*but she wants maneuvering to be* an absolutley no-brainer operation.

Can't do that with shafts, props, shift levers,*and rudders.* You can do it with pod drives.

It's my understanding that the pod drives are designed to shear off outside the hull if they strike something.* So no big hole in the bottom of the boat.** Pricey to replace, I'm sure, but so are shafts, props, rudders, V-struts and bottom damage.

Nomad Willy · Jan 10, 2011

Hey Lurker,Speak'in of going aground it looks like you hav'nt got any problem w that judging by your avitar. *Efficiency? I don't think the average yachtsman's going to pay for his pod drives w fuel savings. As to my twin keel idea one would make the keels smaller and skinnier and faired on the trailing edge so the drag should be about the same. The same as the original keel not the pods. And if a guy said no the the pods he could prolly buy a 5 or 10' bigger boat w the savings. I'd much rather have a diesel electric drive or a completely custom boat w the savings from saying no to pod drive. Just say no to pods.

JD · Jan 10, 2011

Moonstruck wrote:

*
JD wrote:* Maybe we need to take our heads out and keep a better watch.* Well at least if we have Pods.JD, I think that you are in NC.* Watch it at the Alligator River entrance,*in Bogue Sound, both channels going into Beaufort, behind Bogue Inlet, at the White Oak River junction at Swansboro, behind Bear Inlet, New River crossing,*behind Carolina Beach, and Snow's Cut just to name a few.* You don't have to be out of the marked channel to run aground.* That is just one section of the ICW.* Those Tow Boat/US and Seatow boats don't hang around for nothing.

I subscribe to the theory that those that cruise the ICW and haven't run aground probably will.* I operate my boat accordingly.* My charts are full of notes.* The above was from memory.* The charts are on the boat.
__________________________________________________

Moonstruck,

I have been through almost all of those places and a few more here in NC with two different sailboats of over 5' 6"*draft.* For the most part if you stay in the channel you will be just fine.* Now I'm not talking about the channel on your chart plotter, I'm talking about looking forward and aft at the markers.* The channel does change and here in NC you must look out for the cans and nuns, not to mention the occasional green floater*or red ball.* I have run aground several times with the sailboat but one time was my fault (didn't pick up the markers switching sides at Oregon Inlet and Old House Channel*due to a dredge in operation) and one time two years ago in Adams Creek when a 60' Sportfish rolled me out of the channel with his wake.***Ocracoke Inlet is a tough one but all you have to do is ask for help from any*one of the Ferry Captains or the USCG station*and they will advise you as to where the problems are.* It is usually at G11 that the shoaling happens and there usually are a couple of cans out.* If you line up the Day Marks and don't see the cans you are going to bump.*

I think if you use common sense and are careful there won't be much of a problem.* BTW common sense includes looking out side at the*Day Marks, looking at the chart plotter and also looking at the depth finder.* The Ocracoke Inlet is 12' for the most part and when the depth finder starts reading 6' you are headed the wrong way.*

*

Conventional or POD Drives?

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