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Old 01-02-2013, 05:52 PM   #121
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A hypothetical question to all: If you were employed as a captain by a Brokerage in Florida that needed to move one of their two new Krogen 58's to Costa Rica and the boss gave you the choice of either taking the one with twins or the single screw, which one would you pick?
That's a no-brainer for me and my wife. We have no interest in running a single engine boat anywhere, let alone to Costa Rica.
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Old 01-02-2013, 05:54 PM   #122
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A hypothetical question to all: If you were employed as a captain by a Brokerage in Florida that needed to move one of their two new Krogen 58's to Costa Rica and the boss gave you the choice of either taking the one with twins or the single screw, which one would you pick?
Being an ACTUAL delivery captain...I would take whichever I was hired for...I've moved twins that never made it 100 yards to the fuel dock because the impellers had taken a set from 2 years on the hard...4 hrs later and I was still on my way...had it been a single..it would have been 3 hours and on my way.

Your question is idiotic...world class boats designed with one engine...ready and raring to go and you wouldn't go? I wouldn't either without tools and parts...but that would be the only reason.
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Old 01-02-2013, 06:09 PM   #123
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I guess I'm late to this....but there was a question to me specifically, somewhere a long ways back.......

There is no better or worse, good or bad, only different answers to every users slightly different requirements. While one person's priority is maneuverability, another's is redundancy, someone else is worried about efficiency, and all are concerned with cost......

In the Gulf of Alaska a big tug with an extremely valuable tow lost power in all four engines yesterday....now the tow is on the beach.....not sure if that's 300% redundancy but it didn't help.......fuel issues were mentioned....

A number of Nordhavn's have required use of the "get home" or pony engine. The 40' that went round the world used it a couple of times, once for a cooling/wet exhaust issue......A 62' used theirs on a crossing from US West Coast to Tahiti, and found it could not quite keep the bow into wind and big sea while they dealt with a cooling/wet exhaust issue. A bit scary and Nordhavn upped the pony size after that......

A single engine/shaft/prop will cost less to install, is lower drag and deeper draft, and a single larger prop turning more slowly is more efficient than smaller diameter props turning faster......For the ultimate in propulsion efficiency see the Marco Polo line currently produced by Cheoy Lee.....one big multi-bladed prop turning very slowly with twin rudders outside it (for prop protection).....

But the single offers zero redundancy....this is not acceptable to some folks. Some are okay with the pony engine concept. A small engine with it's own shaft and folding (for low drag when not in use - 99% of the time) prop....no rudder....Hummm? What are the statistics on steering failure? Auxiliary steering gear is of prime importance in the commercial boat and ship world......Again see the Marco Polo, two rudders (100% redundancy).

In my experience, if an engine is left to sit idle all it's life, it will fail when asked to operate under heavy load in some desperate situation.....So my take is that if you must have some redundancy, use it every day to be ready for that failure you know is coming.......This is why I conceived the use of smaller twin engines in my Passagemaker Lite series......Since the original we've gone smaller (the 39') with a single engine, to suit a particular client.

All my personal experience, including month long fishing trips offshore, have been in single (propulsion) engine boats. In thousands of hours and lots of breakdowns of various types, the only time I've been towed due to engine failure was with an old 60HP Mercury outboard when I was 17 years old.....
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Old 01-02-2013, 06:24 PM   #124
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I guess I'm late to this....but there was a question to me specifically, somewhere a long ways back.......
Thanks for your perspective, Tad.

This was the question from post #38:

"I'd love to hear Tad Roberts' perspective on the advantages, disadvantages, practicality and costs of protective bilge keels on twin recreational trawlers in the 30-45 foot range. I've often thought that they would provide the needed protection and roll stability on twin boats (like mine!!) that lack both. "
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Old 01-02-2013, 07:17 PM   #125
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Being an ACTUAL delivery captain...I would take whichever I was hired for...I've moved twins that never made it 100 yards to the fuel dock because the impellers had taken a set from 2 years on the hard...4 hrs later and I was still on my way...had it been a single..it would have been 3 hours and on my way.

Your question is idiotic...world class boats designed with one engine...ready and raring to go and you wouldn't go? I wouldn't either without tools and parts...but that would be the only reason.
Relax Captain. The hypothetical question as well as this thread is just for fun. If you don't like it just ignore it.

So if the choice was yours which KK58 would you pick? I'm just teasin'.
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Old 01-02-2013, 07:51 PM   #126
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Thanks for your perspective, Tad.

This was the question from post #38:

"I'd love to hear Tad Roberts' perspective on the advantages, disadvantages, practicality and costs of protective bilge keels on twin recreational trawlers in the 30-45 foot range. I've often thought that they would provide the needed protection and roll stability on twin boats (like mine!!) that lack both. "
Fly....

I would refer to them as skegs rather than bilge keels which to my mind are something completely different. Advantages would be they provide the necessary prop/rudder protection, and as you mention some added roll damping and upright drying out. Main disadvantage is added drag and expense.

But it's really a problem if you have a typical mid engine type boat. Often they have a fairly shallow shaft angle and a lot of shaft is exposed below the hull (sometimes with two struts on each shaft). I believe some Grand Banks are this way. The fixed skeg then has to become really long to fully enclose the shaft, not practical. I have used them on the PL series boats (in conjunction with prop pockets) but that's using high shaft angles (which adds some loss) and vee drives.
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Old 01-02-2013, 08:05 PM   #127
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The Great Harbor boats have twin engines with each prop protected by a skeg.

All the Grand Banks twin engine models except the new pod-drive boats have long shafts supported by one or two struts.
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Old 01-02-2013, 08:11 PM   #128
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Fly....

I would refer to them as skegs rather than bilge keels which to my mind are something completely different. Advantages would be they provide the necessary prop/rudder protection, and as you mention some added roll damping and upright drying out. Main disadvantage is added drag and expense.

But it's really a problem if you have a typical mid engine type boat. Often they have a fairly shallow shaft angle and a lot of shaft is exposed below the hull (sometimes with two struts on each shaft). I believe some Grand Banks are this way. The fixed skeg then has to become really long to fully enclose the shaft, not practical. I have used them on the PL series boats (in conjunction with prop pockets) but that's using high shaft angles (which adds some loss) and vee drives.
Thanks much for that reply. I really appreciate your perspective and contributions!
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Old 01-02-2013, 09:34 PM   #129
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Relax Captain. The hypothetical question as well as this thread is just for fun. If you don't like it just ignore it.

So if the choice was yours which KK58 would you pick? I'm just teasin'.
I AM relaxed...why in the world would you think I'm not?

I'm on a 4 month cruise till my work (if you can call it that) starts up again?

I wouldn't pick either if I had a choice...even for my own boat...as for doing it for a job???? Like I said...whichever I'm assigned and it's properly outfitted for the trip....
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Old 01-02-2013, 10:14 PM   #130
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Bruce K said:

"Marin, just how do you do that, so that the undriven gearbox is not being turned by the prop?"

Bruce, many transmissions/gear boxes do just fine rotating on a "dead" engine. Our Hurth book says no problem trailing the prop, which we indeed have been forced to do with no overheat resulting. Your manual should specify if it is a problem.
Interesting thought Tom. BW manual I previously downloaded for Velvet Drive 70C and 71C models (I have to check the plates on my transmissions the identifiers in my IG Manual are 10-13-000-003&4) has this:
"Freewheeling.
Under sail with the propeller turning, or at trolling speeds with one of 2 engines shut down, the design of the Velvet Drive gear maintains adequate cooling and lubrication"

Plenty of sailboats do 7 knots, an old trawler like mine should not exceed that on 1 engine. New Years Day I ran the boat after installing a thermostat in the port engine where there was none ( slow to warm, not reaching full temp),thinking it would be ok having renewed heat exchanger, oil cooler,and fixed the raw water pump. It overheated. At slower speed it was just ok, so I ran it only slowly going home. All was well next day with thermostat removed. Now the cause. New AD supplied thermostat came out dirty, maybe I need to flush the fresh water side, I`m yet to boil test the thermostat but doubt it`s at fault. Then query the fresh water pump.
Glad I had twins that day!
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Old 01-02-2013, 11:37 PM   #131
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BruceK the identifiers in my IG Manual are 10-13-000-003&4) has this:
"Freewheeling.
Under sail with the propeller turning, or at trolling speeds with one of 2 engines shut down, the design of the Velvet Drive gear maintains adequate cooling and lubrication"

A while back there was an extensive discussion on what constituted 'trolling' speed, I think 3-4 knots was the agreed figure
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Old 01-02-2013, 11:43 PM   #132
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What is the agreed-upon "under sail" speed? Many of my friends sail at 6-7 kts.
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Old 01-03-2013, 05:51 AM   #133
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A hypothetical question to all: If you were employed as a captain by a Brokerage in Florida that needed to move one of their two new Krogen 58's to Costa Rica and the boss gave you the choice of either taking the one with twins or the single screw, which one would you pick?
How much time do I have and who's paying for fuel?

New boat deliveries are tough because they can suffer from what I call SID (sudden infant death). If something is going to fail on a new boat or a new system, it seems to happen with in the first 30 days.

Now if you asked if someone was to give me a new Krogen 58 and I had my choice of engines, I'd take the single.
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Old 01-03-2013, 06:58 AM   #134
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New boat deliveries are tough because they can suffer from what I call SID (sudden infant death).

You bet , after the first 500 hours , with book maint, the failure rate should be close to ZERO.
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Old 01-03-2013, 10:37 AM   #135
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I AM relaxed...why in the world would you think I'm not?

I'm on a 4 month cruise till my work (if you can call it that) starts up again?

I wouldn't pick either if I had a choice...even for my own boat...as for doing it for a job???? Like I said...whichever I'm assigned and it's properly outfitted for the trip....
My bad Capt. When you called my game idiotic and refuse to give an answer, It gave me the impression that you were anything but relaxed.
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Old 01-03-2013, 10:49 AM   #136
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How much time do I have and who's paying for fuel?

New boat deliveries are tough because they can suffer from what I call SID (sudden infant death). If something is going to fail on a new boat or a new system, it seems to happen with in the first 30 days.

Now if you asked if someone was to give me a new Krogen 58 and I had my choice of engines, I'd take the single.
Time is unlimited and fuel is provided by the dealer.

Larry, as a Krogen guy you probably know that even though the KK58 is offered in single and twin configuration, almost all of them are twins and the very rare singles come with a wing engine which I don't really consider a true single screw. But for this game, let's assume that the single is a true single screw.
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Old 01-03-2013, 11:22 AM   #137
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I feel better with a back up power supply. It doesn't have to make sense. But I'd prefer something other than another of the same; just for interest. Back up sail power catches my interest. Really - it is difficult to accurately justify - go for whatever makes you feel at ease. How you maintain whatever you have makes more of a difference than what you have.
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Old 01-03-2013, 11:34 AM   #138
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Time is unlimited and fuel is provided by the dealer.

Larry, as a Krogen guy you probably know that even though the KK58 is offered in single and twin configuration, almost all of them are twins and the very rare singles come with a wing engine which I don't really consider a true single screw. But for this game, let's assume that the single is a true single screw.
A new boat delivery, sure I'd deliver the twin first but only because of SID and I don't know the boat. When I've done deliveries, I bring my own navigation system for the same reason.

As I said before though, I would take the single if someone were to give me one. What can I say, I'm a single kind of guy. If I wasn't, I never would have left Alaska.
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Old 01-03-2013, 11:39 AM   #139
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Single malt scotch, single barrel bourbon, single engine boats. See a patern?
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Old 01-03-2013, 11:40 AM   #140
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"I'd love to hear Tad Roberts' perspective on the advantages, disadvantages, practicality and costs of protective bilge keels on twin recreational trawlers in the 30-45 foot range. I've often thought that they would provide the needed protection and roll stability on twin boats (like mine!!) that lack both. "
Years ago, I was cruising the Sea of Cortez with my brother on his 42' Californian Sport Fisher. We encountered a pod of Killer Whales (Yes...Killer Whales in the Gulf of California) which came up just behind the stern of the boat. We were doing about 10knts & the whales found this to be a nice speed to "play with the boat." One of them dove under the boat and hit the prop shaft on the port side, causing a severe vibration. We limped in to La Paz and had the shaft straightened. Years later, while on a fishing trip, a similar thing happened with a Humpback in SE Alaska. Although I've had 4 twin engine boats since 1995, the fact that those twin shafts hang out in the slip stream is constantly on my mind.
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