On 5/21/2015 9:30 AM, Keyser Söze wrote:
On 5/21/15 9:22 AM, Tim wrote:
I can understand running one engine for a 'trolling' speed. But the OP
was vague on what boat, engines, and purpose he's trying to achieve
besides merely 'saving fuel'

He hasn't been back either. Lol!


A friend has a 25 foot outboard fishing boat with a full transom
bracket. It has a 300 hp Yamaha centered on the platform, and there's a
20 hp outboard mounted on the bracket to the side of the big Yamaha.
Steering bracket connects both to the steering wheels. Nothing unusual
around here. He runs in and out of the harbor on the small outboard, and
also uses it to troll for stripers. The small outboard has no problems
maintaining the 6 mph harbor speed limit.

Nice to know, but not relevant to this discussion. :-)

--

Respectfully submitted by Justan

Laugh of the day from Krause

"I'm not to blame anymore for the atmosphere in here.
I've been "born again" as a nice guy."

On 5/21/15 4:26 PM, wrote:
On Thu, 21 May 2015 09:30:04 -0400, Keyser Söze
wrote:

On 5/21/15 9:22 AM, Tim wrote:
I can understand running one engine for a 'trolling' speed. But the OP was vague on what boat, engines, and purpose he's trying to achieve besides merely 'saving fuel'

He hasn't been back either. Lol!


A friend has a 25 foot outboard fishing boat with a full transom
bracket. It has a 300 hp Yamaha centered on the platform, and there's a
20 hp outboard mounted on the bracket to the side of the big Yamaha.
Steering bracket connects both to the steering wheels. Nothing unusual
around here. He runs in and out of the harbor on the small outboard, and
also uses it to troll for stripers. The small outboard has no problems
maintaining the 6 mph harbor speed limit.

Before the 4 stroke showed up, kickers were very popular. Now it seems
pretty unnecessary.


I'll be sure to share that bit of info with the guys I know and see who
have their fishing boats rigged that way.

Your point is well taken. I would never try to put the boat on a plane with only one engine. I was more thinking of trolling at low rpm on one engine.
I would still want to block the dead shaft, but still have not quite figured out how. Appreciate your input.

wenders wrote:
Wayne.B;1034351 Wrote:
On Tue, 19 May 2015 05:24:54 +0100, wenders
wrote:
-

If I shut down one of my engines to save fuel, am I supposed to block
the shaft of the dead engine in order to protect the transmission? And
what is the best way to do this?-

===

I've had numerous conversations with my mechanic and others on this
subject. The problem arises because the transmission depends on
circulation of oil for lubrication and cooling. The pump which
creates that circulation is driven by the engine side.

Some say that if you run slowly (under 7 kts or so), that there is
little or no risk. I've done this on numerous occassions without
experiencing any problems, and have observed no abnormal temperatures
as measured by an IR heat gun. Others say that it's OK if you briefly
restart the engine every hour or so to ensure lubrication.

On the other hand both my mechanic and the transmission manufacturer
(Twin Disc) strongly recommend against it, and consequently I have
stopped doing it. The generally accepted method of securing the shaft
from rotation is to chain it down, i.e., wrap the coupler with chain
and fasten it to a strong point on the boat. Obviously this has to be
done with the boat stopped.

There is a secondary issue that you may not be aware of. The shaft
log and/or cutlass bearing frequently rely on a flow of cooling water
from the engine raw water system to prevent wear and over heating. If
the associated engine is shut down, that flow will no longer be
present unless you have installed cross over hoses from the opposite
engine.

Bottom line for me is that the risks out weigh the potential fuel
savings. Rebuilding or replacing a transmission costs many thousands
of dollars plus the inconvenience and down time. Chaining down the
shaft is tricky and has its own risks. A possible alternative is to
leave the engine running at idle speed instead of shutting it down.
Diesel engines do not like to idle for long periods of time however
and will eventually develop carbon deposits and/or stuck rings.

Your point is well taken. I would never try to put the boat on a plane
with only one engine. I was more thinking of trolling at low rpm on one
engine.
I would still want to block the dead shaft, but still have not quite
figured out how. Appreciate your input.





Maybe there is a place for a device like the emergency brake on the 40's
Plymouth. Was a brake on the drive shaft. Would not be that hard to
implement.

Bill, I take it you're talking about a band brake?

Tim wrote:
Bill, I take it you're talking about a band brake?

Yup. But you could implement a small mechanical disk brake also.

Wayne.B wrote:
On Wed, 20 May 2015 20:03:00 -0400, Username
wrote:

wrote:
On Tue, 19 May 2015 05:24:54 +0100, wenders
wrote:

If I shut down one of my engines to save fuel, am I supposed to block
the shaft of the dead engine in order to protect the transmission? And
what is the best way to do this?
Dunno much about inboards but the outboard guys say you really should
swap props if you are running on one engine to prevent "lugging". If
it was properly propped to run 2 in the power band, one is going to be
straining at much more than hull speed.

Most twins have counter-rotating props. Swapping them would make you
run in reverse.
===

I think you misunderstood his comment. He did not mean swapping them
port to starboard and vice versa. He meant swapping them for new
props with a lower pitch, sort of like shifting to a lower gear.


You are probably right. I'm not afraid to admit when I'm wrong!

On Sat, 23 May 2015 06:55:21 -0400, wrote:

If you think you need the kicker for a backup, that may be another
issue but it is just going to get old and rot on that bracket. It is
cheaper to sell it and buy a tow pirate contract

===

I agree if you do all of your boating within cell phone or VHF range.
But if you go 40 or 50 miles offshore, twin engines of some sort have
a lot to recommend them.

On Sun, 24 May 2015 08:54:52 -0400, wrote:

On Sat, 23 May 2015 09:42:08 -0400, Wayne.B
wrote:

On Sat, 23 May 2015 06:55:21 -0400, wrote:

If you think you need the kicker for a backup, that may be another
issue but it is just going to get old and rot on that bracket. It is
cheaper to sell it and buy a tow pirate contract

===

I agree if you do all of your boating within cell phone or VHF range.
But if you go 40 or 50 miles offshore, twin engines of some sort have
a lot to recommend them.

This is where the discussion of the prop deal came about, on the real
boat board. Trying to idle home from 50 miles out or half way to the
Bahamas is not that attractive. That is where carrying a set of spare
props with "single prop pitch" came in but it would need to be slick
calm to be able to swap props at sea. On an inboard you are diving.
If I was going to do this I might look into that system with the
standard hub and replaceable blades for my spare.

===

None of the alternatives are real good if you lose an engine in the
Gulf Stream. You don't really need to run at idle speed however, it
will just seem that way if you're used to running on plane at 25 kts
or so. You can actually cover quite a bit of ground at 7 or 8 kts if
you have the patience to tough it out. Don't ask me how I know. :-)

Wayne.B wrote:
On Sun, 24 May 2015 08:54:52 -0400, wrote:

On Sat, 23 May 2015 09:42:08 -0400, Wayne.B
wrote:

On Sat, 23 May 2015 06:55:21 -0400, wrote:

If you think you need the kicker for a backup, that may be another
issue but it is just going to get old and rot on that bracket. It is
cheaper to sell it and buy a tow pirate contract

===

I agree if you do all of your boating within cell phone or VHF range.
But if you go 40 or 50 miles offshore, twin engines of some sort have
a lot to recommend them.

This is where the discussion of the prop deal came about, on the real
boat board. Trying to idle home from 50 miles out or half way to the
Bahamas is not that attractive. That is where carrying a set of spare
props with "single prop pitch" came in but it would need to be slick
calm to be able to swap props at sea. On an inboard you are diving.
If I was going to do this I might look into that system with the
standard hub and replaceable blades for my spare.

===

None of the alternatives are real good if you lose an engine in the
Gulf Stream. You don't really need to run at idle speed however, it
will just seem that way if you're used to running on plane at 25 kts
or so. You can actually cover quite a bit of ground at 7 or 8 kts if
you have the patience to tough it out. Don't ask me how I know. :-)

When I go on long range tuna trips out of San Diego, most of the trip
cruising is at 9-11 knots. And on a 7-8 day we end up as far south as
Rocas alijos. 460 miles from Point Loma harbor.