Fascinating new drive system from Volvo
 

Yeah, and at over 40 knots!

http://groups.msn.com/FishWishersHomePage
(Formerly MowerKing)

Very interesting.

I'm not sure I believe this part:

In the high-speed scenario, the leg and pod will shear off flush with the
hull. The lower bearing carrier has been engineered specially to break at a
point below the O-ring seal between the fixed and steerable parts of the
drive. As the leg bends backwards, the vertical drive shaft simply pulls out
of its spline. The inside of the transmission is now open to the ocean but
no water can escape into the boat and the vital mounting joint between
transmission and hull will remain not only intact but undamaged thanks to
the energy absorption of the big twin O-rings.

Leading with the prop?

That should work well in the log infested waters up this way. (not).

I assume that Tiara will offer this as an available upcharged option, not as
standard equipment?

Every so often, somebody tries to reinvent the wheel.

In article , WaIIy To wrote:

http://www.ybw.com/auto/newsdesk/200...42mbynews.html


Tiara is going to use it.

Forward facing propellors with no protection eh?

That ought to be interesting the first time you hit something solid at 40
knots.

Oh yeah, I read the part about the leg shearing off and not puncturing the
hull. Uh huh. And if that seal fails? Exactly how big is that mounting
hole? Bet 'ya can't jam a wooden plug in THAT slot.

--
--
Karl Denninger ) Internet Consultant & Kids Rights Activist
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"Karl Denninger" wrote in message
news:dfIvd.5060$jn.4591@lakeread06...

In article , WaIIy To
wrote:

http://www.ybw.com/auto/newsdesk/200...42mbynews.html


Tiara is going to use it.

Forward facing propellors with no protection eh?

That ought to be interesting the first time you hit something solid at 40
knots.

Oh yeah, I read the part about the leg shearing off and not puncturing the
hull. Uh huh. And if that seal fails? Exactly how big is that mounting
hole? Bet 'ya can't jam a wooden plug in THAT slot.

Wouldn't it also throw debris upward into the hull as well if it caught the
upward spin of the prop?



--
--
Karl Denninger ) Internet Consultant & Kids Rights
Activist
http://www.denninger.net My home on the net - links to everything I do!
http://scubaforum.org Your UNCENSORED place to talk about DIVING!
http://www.spamcuda.net SPAM FREE mailboxes - FREE FOR A LIMITED TIME!
http://genesis3.blogspot.com Musings Of A Sentient Mind

"Harry Krause" wrote in message
...
WaIIy wrote:

http://www.ybw.com/auto/newsdesk/200...42mbynews.html


Tiara is going to use it.



Forward facing props unprotected by any sort of skeg, with the units
coming out through a hole in the bottom of the boat?

Fascinating!

You didn't finish reading Harry.

Eisboch

"Harry Krause" wrote in message
...
Eisboch wrote:
"Harry Krause" wrote in message
...

WaIIy wrote:

http://www.ybw.com/auto/newsdesk/200...42mbynews.html


Tiara is going to use it.



Forward facing props unprotected by any sort of skeg, with the units
coming out through a hole in the bottom of the boat?

Fascinating!


You didn't finish reading Harry.

Eisboch



Yeah, I did. I wouldn't own an inboard with a rear-facing wheel unless
it were at least partially protected by a keel and skeg. The new Volvo
unit is totally unprotected. And I wouldn't want to depend upon the unit
simply breaking off under the hull without it creating a huge hole in
the bottom of the boat.

No more risk than a shaft, cutlass bearing mount, prop and rudder on a true
inboard without a keel. I saw a 43' Post that hit a rock going through
Wood's Hole last summer. It had a 1' by 2' hole in the bottom where the
port shaft went through the hull. Both shafts looked like bananas and the
props were, well they weren't anymore.

From what I read about the new Volvo drive, it has a pre-engineered break
point that will not result in a swamped boat.

Eisboch

System is being used on many large cruise ships (well, similar) it's
called azipods. as for protection .... hey add some kort nozzles.

Biggest problem? Forget the possible damage stuff .... for those with twin
screw experience, you'll have to forget everything you learned, be they
inboards or I/O's, and learn a whole new way of boat handling..... and for
many, it will be impossible.

Shen

"Gary" wrote in message
...


Very interesting.

I'm not sure I believe this part:

In the high-speed scenario, the leg and pod will shear off flush with the
hull. The lower bearing carrier has been engineered specially to break at
a
point below the O-ring seal between the fixed and steerable parts of the
drive. As the leg bends backwards, the vertical drive shaft simply pulls
out
of its spline. The inside of the transmission is now open to the ocean but
no water can escape into the boat and the vital mounting joint between
transmission and hull will remain not only intact but undamaged thanks to
the energy absorption of the big twin O-rings.





And hearing how much parts for Volvo's cost, this should result in an
undamaged hull, but a really damaged checking account.

On Wed, 15 Dec 2004 04:04:15 GMT, "Calif Bill"
wrote:


"Gary" wrote in message
...


Very interesting.

I'm not sure I believe this part:

In the high-speed scenario, the leg and pod will shear off flush with the
hull. The lower bearing carrier has been engineered specially to break at
a
point below the O-ring seal between the fixed and steerable parts of the
drive. As the leg bends backwards, the vertical drive shaft simply pulls
out
of its spline. The inside of the transmission is now open to the ocean but
no water can escape into the boat and the vital mounting joint between
transmission and hull will remain not only intact but undamaged thanks to
the energy absorption of the big twin O-rings.

And hearing how much parts for Volvo's cost, this should result in an
undamaged hull, but a really damaged checking account.

And, like most things that have Volvo stamped on them, incredible and
astronomic repair bills because the damn things are over engineered.

Later,

Tom

On Wed, 15 Dec 2004 06:40:23 -0500, Harry Krause
wrote:

Short Wave Sportfishing wrote:
On Wed, 15 Dec 2004 04:04:15 GMT, "Calif Bill"
wrote:


"Gary" wrote in message
...


Very interesting.

I'm not sure I believe this part:

In the high-speed scenario, the leg and pod will shear off flush with the
hull. The lower bearing carrier has been engineered specially to break at

a

point below the O-ring seal between the fixed and steerable parts of the
drive. As the leg bends backwards, the vertical drive shaft simply pulls

out

of its spline. The inside of the transmission is now open to the ocean but
no water can escape into the boat and the vital mounting joint between
transmission and hull will remain not only intact but undamaged thanks to
the energy absorption of the big twin O-rings.

And hearing how much parts for Volvo's cost, this should result in an
undamaged hull, but a really damaged checking account.

And, like most things that have Volvo stamped on them, incredible and
astronomic repair bills because the damn things are over engineered.

More impressive would have been an outdrive that tips completely out of
the water.

ROTFL!!!

Exactly - something actually useful. :)

Later,

Tom

On Tue, 14 Dec 2004 15:44:55 -0500, Harry Krause
wrote:

Karl Denninger wrote:
In article , WaIIy To wrote:

http://www.ybw.com/auto/newsdesk/200...42mbynews.html


Tiara is going to use it.


Forward facing propellors with no protection eh?

That ought to be interesting the first time you hit something solid at 40
knots.

Oh yeah, I read the part about the leg shearing off and not puncturing the
hull. Uh huh. And if that seal fails? Exactly how big is that mounting
hole? Bet 'ya can't jam a wooden plug in THAT slot.

--


Damn, Karl...I know this will make you nervous, but we're in total
agreement on this.

Don't take any drastic measures!

Here's another one for ya'. I'm also in total agreement. The whole
concept, despite their attempts at designing for minimum damage, seems
to be a recipe for a sunk boat.

Dave

On Tue, 14 Dec 2004 16:40:29 GMT, WaIIy
wrote:



http://www.ybw.com/auto/newsdesk/200...42mbynews.html


Tiara is going to use it.


While I applaud any advances in technology as applied to marine
propulsion, I see a few points that really bother me.

1. Despite the review's attempt to sell this as equivalent in
simplicity and maintenance as a straight shaft drive, it has far more
parts, and more closely resembles an outdrive than a straight shaft
drive.

2. Unprotected props pulling the boat? Again they attempt to put the
reader at ease when the obvious question of striking an underwater
object comes up. But I doubt that there are any guarantees. If that
drive sheers backward at 40 MPH, what's to stop it from punching a
hole in the hull directly behind the mount? Even if the drive sheers
off as designed, it's not going to be a cheap fix.

Dave

In article t,
otnmbrd wrote:


System is being used on many large cruise ships (well, similar) it's
called azipods. as for protection .... hey add some kort nozzles.

There's a HUGE difference between how its done on a cruise ship and this....
--
--
Karl Denninger ) Internet Consultant & Kids Rights Activist
http://www.denninger.net My home on the net - links to everything I do!
http://scubaforum.org Your UNCENSORED place to talk about DIVING!
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In article ,
Dave Hall wrote:


On Tue, 14 Dec 2004 15:44:55 -0500, Harry Krause
wrote:

Karl Denninger wrote:
In article , WaIIy To wrote:

http://www.ybw.com/auto/newsdesk/200...42mbynews.html


Tiara is going to use it.


Forward facing propellors with no protection eh?

That ought to be interesting the first time you hit something solid at 40
knots.

Oh yeah, I read the part about the leg shearing off and not puncturing the
hull. Uh huh. And if that seal fails? Exactly how big is that mounting
hole? Bet 'ya can't jam a wooden plug in THAT slot.

--


Damn, Karl...I know this will make you nervous, but we're in total
agreement on this.

Don't take any drastic measures!

Here's another one for ya'. I'm also in total agreement. The whole
concept, despite their attempts at designing for minimum damage, seems
to be a recipe for a sunk boat.

Dave

It'll be interesting to watch how this one plays out.

Until a few people run over a manatee with one (heh heh), or hit something
offshore, I'm not sold.

I've not managed to rip a screw off my boat or do significant damage, but I
have had some dings to the props over the last few years. You do your
damndest to avoid it, but it DOES happen.

Second, exactly how expensive is damage to that underwater unit if/when it
happens? What will one of those units plus whatever is trashed on the
mounting ring cost to replace?

Finally, I'm not sold on the wisdom of engines under the cockpit sole. I
know its a popular setup (V-drives and all), but it tends to make trim a bit
interesting with all that mass aft. And given recent trends, I'm more than
a bit concerned about service access.

--
--
Karl Denninger ) Internet Consultant & Kids Rights Activist
http://www.denninger.net My home on the net - links to everything I do!
http://scubaforum.org Your UNCENSORED place to talk about DIVING!
http://www.spamcuda.net SPAM FREE mailboxes - FREE FOR A LIMITED TIME!
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In article ,
P.Fritz wrote:



"Karl Denninger" wrote in message
news:dfIvd.5060$jn.4591@lakeread06...

In article , WaIIy To
wrote:

http://www.ybw.com/auto/newsdesk/200...42mbynews.html


Tiara is going to use it.

Forward facing propellors with no protection eh?

That ought to be interesting the first time you hit something solid at 40
knots.

Oh yeah, I read the part about the leg shearing off and not puncturing the
hull. Uh huh. And if that seal fails? Exactly how big is that mounting
hole? Bet 'ya can't jam a wooden plug in THAT slot.

Wouldn't it also throw debris upward into the hull as well if it caught the
upward spin of the prop?

That'd be delicious.

Your leg shears off cleanly, but the drive unit flips upward and punctures
the hull on the way off.

--
--
Karl Denninger ) Internet Consultant & Kids Rights Activist
http://www.denninger.net My home on the net - links to everything I do!
http://scubaforum.org Your UNCENSORED place to talk about DIVING!
http://www.spamcuda.net SPAM FREE mailboxes - FREE FOR A LIMITED TIME!
http://genesis3.blogspot.com Musings Of A Sentient Mind

My first thought when I saw this was, "Why is the engine so far behind
the outdrive and why is the skeg slanted backward??" Then I realized
that the prop was facing forward!! This sounds like something Ed
Faegol might have dreamed up......

Karl Denninger wrote:
In article t,
otnmbrd wrote:


System is being used on many large cruise ships (well, similar) it's
called azipods. as for protection .... hey add some kort nozzles.


There's a HUGE difference between how its done on a cruise ship and this....
--

I don't know that I'd call it a "huge" difference. Unless I mis read,
it's a pod unit which pivots 360 deg and is normally set up to pull
rather than push. Biggest difference I see is that most azipod units on
ships that I know of, have the motor in the pod.

otn

"WaIIy" wrote in message
...

http://www.ybw.com/auto/newsdesk/200...42mbynews.html

Tiara is going to use it.

This is going to be a nightmare. Look at the schematic and
read what will happen to the drive under impact.

Yeah - I really want the drive unit to break off and sit
on the bottom.

Are you sure it's not April 1st over in Sweden?

In article ,
Shen44 wrote:


Subject: Fascinating new drive system from Volvo
From: WaIIy
Date: 12/14/2004 9:56 PM Pacific Standard Time
Message-id:

On 15 Dec 2004 03:37:39 GMT, (Shen44) wrote:

Biggest problem? Forget the possible damage stuff .... for those with twin
screw experience, you'll have to forget everything you learned, be they
inboards or I/O's, and learn a whole new way of boat handling..... and for
many, it will be impossible.

Shen

Good point, it's something new, so it will be impossible to learn.

Duh



BG First off, in reading over the "press release", I'm not sure that this
unit is set up as I first thought. (360* azimuthing).
If, however, it is, then there will be a big learning curve, which some will
never master.
On Z-drives, those who have the greatest problems are generally those who have
a long history of standard twin screw, since you have to throw out everything
you learned, make sure you forget it and learn a totally new system which for
many, never becomes "second nature".

Shen

You can drive this as a standard twin-screw boat around the docks. Leave
the wheel centered and use differential thrust with the gears. My
understanding is that the system does not interfere with this.

--
--
Karl Denninger ) Internet Consultant & Kids Rights Activist
http://www.denninger.net My home on the net - links to everything I do!
http://scubaforum.org Your UNCENSORED place to talk about DIVING!
http://www.spamcuda.net SPAM FREE mailboxes - FREE FOR A LIMITED TIME!
http://genesis3.blogspot.com Musings Of A Sentient Mind

In article ,
otnmbrd wrote:


Karl Denninger wrote:
In article t,
otnmbrd wrote:


System is being used on many large cruise ships (well, similar) it's
called azipods. as for protection .... hey add some kort nozzles.


There's a HUGE difference between how its done on a cruise ship and this....
--

I don't know that I'd call it a "huge" difference. Unless I mis read,
it's a pod unit which pivots 360 deg and is normally set up to pull
rather than push. Biggest difference I see is that most azipod units on
ships that I know of, have the motor in the pod.

otn

The Volvo system does not azimuth 360 degrees. Its more like an outdrive in
its range of motion, among other differences.

Azipod units also aren't usually set up as "pullers".

--
--
Karl Denninger ) Internet Consultant & Kids Rights Activist
http://www.denninger.net My home on the net - links to everything I do!
http://scubaforum.org Your UNCENSORED place to talk about DIVING!
http://www.spamcuda.net SPAM FREE mailboxes - FREE FOR A LIMITED TIME!
http://genesis3.blogspot.com Musings Of A Sentient Mind

"S. N. Ot" wrote in message
k.net...

"WaIIy" wrote in message
...

http://www.ybw.com/auto/newsdesk/200...42mbynews.html

Tiara is going to use it.

This is going to be a nightmare. Look at the schematic and
read what will happen to the drive under impact.

Yeah - I really want the drive unit to break off and sit
on the bottom.

Are you sure it's not April 1st over in Sweden?



So, what happens when you hit a rock or log at 25 knots with an Alpha or
Bravo drive?

Eisboch

"Eisboch" wrote in message
...

"S. N. Ot" wrote in message
k.net...

"WaIIy" wrote in message
...

http://www.ybw.com/auto/newsdesk/200...42mbynews.html

Tiara is going to use it.

This is going to be a nightmare. Look at the schematic and
read what will happen to the drive under impact.

Yeah - I really want the drive unit to break off and sit
on the bottom.

Are you sure it's not April 1st over in Sweden?



So, what happens when you hit a rock or log at 25 knots with an Alpha or
Bravo drive?

Eisboch

Well when I hit a log at that speed, I lost a blade off the prop and about
3" off the skedge (sp?)

In article ,
Eisboch wrote:



"S. N. Ot" wrote in message
nk.net...

"WaIIy" wrote in message
...

http://www.ybw.com/auto/newsdesk/200...42mbynews.html

Tiara is going to use it.

This is going to be a nightmare. Look at the schematic and
read what will happen to the drive under impact.

Yeah - I really want the drive unit to break off and sit
on the bottom.

Are you sure it's not April 1st over in Sweden?



So, what happens when you hit a rock or log at 25 knots with an Alpha or
Bravo drive?

Eisboch

The nosecone is frequently destroyed or severely damaged, and often the prop
is too. The nosecone and housing, however, are clearly stronger than the
props on this thing!

However, it is on a swivel bracket and the hydraulic rams that control trim
will be destroyed before the unit is completely dismounted, leaving a huge
hole in the boat.

As such you're going to do a lot of damage, but its not all that likely to
sink you.

--
--
Karl Denninger ) Internet Consultant & Kids Rights Activist
http://www.denninger.net My home on the net - links to everything I do!
http://scubaforum.org Your UNCENSORED place to talk about DIVING!
http://www.spamcuda.net SPAM FREE mailboxes - FREE FOR A LIMITED TIME!
http://genesis3.blogspot.com Musings Of A Sentient Mind

Karl Denninger wrote:
Azipod units also aren't usually set up as "pullers".

Azipod is a trade name registered to the ABB corporation. Azipods are
podded azimuthing electric drives, and their design is based on placing
the propeller forward in undisturbed wake for highest efficiency.

You may be thinking of what are called "Z-drives" that are mounted on
tugboats and other small vessels. "Z-drives" are not Azipods but they
are azimuthing thrusters and may or may not incorporate a nozzle.

Rick

On Wed, 15 Dec 2004 17:02:27 -0500, "Eisboch"
wrote:


"S. N. Ot" wrote in message
nk.net...

"WaIIy" wrote in message
...

http://www.ybw.com/auto/newsdesk/200...42mbynews.html

Tiara is going to use it.

This is going to be a nightmare. Look at the schematic and
read what will happen to the drive under impact.

Yeah - I really want the drive unit to break off and sit
on the bottom.

Are you sure it's not April 1st over in Sweden?

So, what happens when you hit a rock or log at 25 knots with an Alpha or
Bravo drive?

I don't think it falls off as this one is designed to do.

Later,

Tom

"Short Wave Sportfishing" wrote in message
...
On Wed, 15 Dec 2004 17:02:27 -0500, "Eisboch"
wrote:


So, what happens when you hit a rock or log at 25 knots with an Alpha or
Bravo drive?

I don't think it falls off as this one is designed to do.

Later,

Tom

I don't know. I've never had the experience, but assume a 15,000 lb boat
doing 25 knots and it hits an unmovable obstruction like a rock ... lemmie
see, energy = mass x velocity squared ... seems to my intuitive analysis,
something's going to give.

Eisboch

On Wed, 15 Dec 2004 18:33:40 -0500, "Eisboch"
wrote:


"Short Wave Sportfishing" wrote in message
.. .
On Wed, 15 Dec 2004 17:02:27 -0500, "Eisboch"
wrote:


So, what happens when you hit a rock or log at 25 knots with an Alpha or
Bravo drive?

I don't think it falls off as this one is designed to do.

I don't know. I've never had the experience, but assume a 15,000 lb boat
doing 25 knots and it hits an unmovable obstruction like a rock ... lemmie
see, energy = mass x velocity squared ... seems to my intuitive analysis,
something's going to give.

You make a good point - I can't argue with it because my experience in
this area is extremely limited.

I've hit things at speed with my outboards and, well to put it
plainly, F'd 'em up pretty bad, but I've never ripped a lower unit off
at speed. Broke a casting once, lost a skeg once and seriously
mangled a prop shaft and prop once.

Then again, neither of my boats weigh 15,000 lbs either.

Later,

Tom

"Short Wave Sportfishing" wrote in message
...

I've hit things at speed with my outboards and, well to put it
plainly, F'd 'em up pretty bad, but I've never ripped a lower unit off
at speed. Broke a casting once, lost a skeg once and seriously
mangled a prop shaft and prop once.

Then again, neither of my boats weigh 15,000 lbs either.

Later,

Tom

When a youngster with a Sears 12' aluminum boat and 7 hp outboard, I seem to
remember leaving the motor unlocked, so if I hit something the motor would
just flip up. (It was embarrassing when you forgot and revved it up in
reverse). Anyway, it just seems to me that a heavy boat at speed isn't
going to stop in time=zero if it hits a rock higher up than the nosecone and
the energy of the impact has to go somewhere. Maybe the leg will stay
together, but the transom will get ripped off.

Eisboch

On Wed, 15 Dec 2004 19:00:24 -0500, "Eisboch"
wrote:


"Short Wave Sportfishing" wrote in message
.. .

I've hit things at speed with my outboards and, well to put it
plainly, F'd 'em up pretty bad, but I've never ripped a lower unit off
at speed. Broke a casting once, lost a skeg once and seriously
mangled a prop shaft and prop once.

Then again, neither of my boats weigh 15,000 lbs either.

When a youngster with a Sears 12' aluminum boat and 7 hp outboard, I seem to
remember leaving the motor unlocked, so if I hit something the motor would
just flip up. (It was embarrassing when you forgot and revved it up in
reverse).

Hell, I still do that. :)

Anyway, it just seems to me that a heavy boat at speed isn't
going to stop in time=zero if it hits a rock higher up than the nosecone and
the energy of the impact has to go somewhere. Maybe the leg will stay
together, but the transom will get ripped off.

The only incident I can compare to was off of Fisher's Island when I
hit a telephone pole type log going 30 or so in my Ranger. It was
just below the surface so I didn't see it until I was right on top of
it. The log hit the motor dead on between the middle section and the
lower unit. Totally cracked the mid section, broke the lower unit
open and mangled the prop shaft and prop.

Fortunately, nobody was hurt, but Sea//Tow had a long tow back to the
launch. :)

Later,

Tom

Eisboch wrote:
"Short Wave Sportfishing" wrote in message
...

On Wed, 15 Dec 2004 17:02:27 -0500, "Eisboch"
wrote:


So, what happens when you hit a rock or log at 25 knots with an Alpha or
Bravo drive?

I don't think it falls off as this one is designed to do.

Later,

Tom


I don't know. I've never had the experience, but assume a 15,000 lb boat
doing 25 knots and it hits an unmovable obstruction like a rock ... lemmie
see, energy = mass x velocity squared ... seems to my intuitive analysis,
something's going to give.

Eisboch


They get damaged the leg/gearcase part mostly badly damaged, but the
leg raises up & usually doesn't rip the transom out of the boat.

The hydraulic rams are designed to allow the stern drive to come up if
there's enough "sudden" force applied. The rams have twin walls &
compound pistons so they can sorta suck a momentary vacuum allowing the
drive to come up. The Volvo ones are similar & older ones had a
mechanical release.


K

In article ,
jetcap wrote:


Karl Denninger wrote:
Azipod units also aren't usually set up as "pullers".

Azipod is a trade name registered to the ABB corporation. Azipods are
podded azimuthing electric drives, and their design is based on placing
the propeller forward in undisturbed wake for highest efficiency.

You may be thinking of what are called "Z-drives" that are mounted on
tugboats and other small vessels. "Z-drives" are not Azipods but they
are azimuthing thrusters and may or may not incorporate a nozzle.

Rick


Yep....

--
--
Karl Denninger ) Internet Consultant & Kids Rights Activist
http://www.denninger.net My home on the net - links to everything I do!
http://scubaforum.org Your UNCENSORED place to talk about DIVING!
http://www.spamcuda.net SPAM FREE mailboxes - FREE FOR A LIMITED TIME!
http://genesis3.blogspot.com Musings Of A Sentient Mind

"K. Smith" wrote in message
...
Eisboch wrote:
"Short Wave Sportfishing" wrote in message
...

On Wed, 15 Dec 2004 17:02:27 -0500, "Eisboch"
wrote:


So, what happens when you hit a rock or log at 25 knots with an Alpha
or
Bravo drive?

I don't think it falls off as this one is designed to do.

Later,

Tom


I don't know. I've never had the experience, but assume a 15,000 lb
boat
doing 25 knots and it hits an unmovable obstruction like a rock ...
lemmie
see, energy = mass x velocity squared ... seems to my intuitive
analysis,
something's going to give.

Eisboch


They get damaged the leg/gearcase part mostly badly damaged, but the
leg raises up & usually doesn't rip the transom out of the boat.

The hydraulic rams are designed to allow the stern drive to come up if
there's enough "sudden" force applied. The rams have twin walls &
compound pistons so they can sorta suck a momentary vacuum allowing the
drive to come up. The Volvo ones are similar & older ones had a
mechanical release.


K

Makes sense. Nice to know they are designed to "give". I can visualize
the leg kicking back which would allow it to provide lift up and over the
object as an inclined plane, so to speak.

Eisboch

Karl Denninger wrote:



The Volvo system does not azimuth 360 degrees. Its more like an outdrive in
its range of motion, among other differences.

Azipod units also aren't usually set up as "pullers".

--

Yup, I mis-read and assumed azimuthing.
Azipods are set up as pullers.

At any rate, although I can see some increased risk for damage to props
and rapping up lines, If the breakaway feature is well designed, it
might be better than driving a set of skegs, props and rudders back up
through the hull .... time will tell.

otn

otnmbrd wrote:
Yup, I mis-read and assumed azimuthing.

You assumed correctly. They are azimuthing thrusters.

Rick

On Wed, 15 Dec 2004 17:02:27 -0500, "Eisboch"
wrote:


"S. N. Ot" wrote in message
nk.net...

"WaIIy" wrote in message
...

http://www.ybw.com/auto/newsdesk/200...42mbynews.html

Tiara is going to use it.

This is going to be a nightmare. Look at the schematic and
read what will happen to the drive under impact.

Yeah - I really want the drive unit to break off and sit
on the bottom.

Are you sure it's not April 1st over in Sweden?



So, what happens when you hit a rock or log at 25 knots with an Alpha or
Bravo drive?


The drive and trim rams are designed to "give" backward to absorb much
of the shock. At slower speeds, you might get away with only prop and
skeg damage. Higher speeds have been known to punch a hole into the
nose cone. I also had a friend who had an unfortunate encounter with a
rock at high speed and it pretty much sheared the drive off at the
gimbal mount. In this particular case, water started to seep in
through what used to be the shaft bellows, but it was not enough that
the bilge pump couldn't keep up until we towed him in

But without that built-in "give", something WILL break.

Dave

On Thu, 16 Dec 2004 07:00:46 -0500, Dave Hall
wrote:

On Wed, 15 Dec 2004 17:02:27 -0500, "Eisboch"
wrote:


"S. N. Ot" wrote in message
ink.net...

"WaIIy" wrote in message
...

http://www.ybw.com/auto/newsdesk/200...42mbynews.html

Tiara is going to use it.

This is going to be a nightmare. Look at the schematic and
read what will happen to the drive under impact.

Yeah - I really want the drive unit to break off and sit
on the bottom.

Are you sure it's not April 1st over in Sweden?



So, what happens when you hit a rock or log at 25 knots with an Alpha or
Bravo drive?

The drive and trim rams are designed to "give" backward to absorb much
of the shock. At slower speeds, you might get away with only prop and
skeg damage. Higher speeds have been known to punch a hole into the
nose cone. I also had a friend who had an unfortunate encounter with a
rock at high speed and it pretty much sheared the drive off at the
gimbal mount. In this particular case, water started to seep in
through what used to be the shaft bellows, but it was not enough that
the bilge pump couldn't keep up until we towed him in

But without that built-in "give", something WILL break.

Even with the give, something will break.

Later,

Tom

Does this remind anyone of an OMC(?) item called Saildrive??? I hope it
works and works well. Volvo seems to be an outfit that takes engineering
seriously. Not too many Volvo orphans out there such as the Yamaha stern
drive.

Butch
"WaIIy" wrote in message
...
On Tue, 14 Dec 2004 20:42:49 GMT, (Karl Denninger)
wrote:


In article , WaIIy To
wrote:

http://www.ybw.com/auto/newsdesk/200...42mbynews.html


Tiara is going to use it.

Forward facing propellors with no protection eh?

That ought to be interesting the first time you hit something solid at 40
knots.

Oh yeah, I read the part about the leg shearing off and not puncturing the
hull. Uh huh. And if that seal fails? Exactly how big is that mounting
hole? Bet 'ya can't jam a wooden plug in THAT slot.

--

Well, I'd guess Volvo and Tiara know a bit about boats.

jetcap wrote:
otnmbrd wrote:

Yup, I mis-read and assumed azimuthing.


You assumed correctly. They are azimuthing thrusters.

Rick

LOL Then I'm back to square one on this system. Like all systems, it
will have advantages and drawbacks which will require more or less care
when operating.
One big disadvantage will probably involve maintenance and repair cost.

otn