Reply
 
Thread Tools Display Modes
 
Old 03-27-2013, 10:04 PM   #821
Guru
 
Moonstruck's Avatar
 
City: Hailing Port: Charleston, SC
Country: USA
Vessel Name: Moonstruck
Vessel Model: Sabre 42 Hardtop Express
Join Date: Nov 2008
Posts: 7,849
Quote:
Originally Posted by RT Firefly View Post
Greetings,
Ya, don't forget twins sink twice as often as singles as well...
Oh, good! I am going to break down 3 times as often, sink twice as often and the expense of maintaining all of that I don't even want to talk about. I think I'm getting the vapors.
__________________
Advertisement

__________________
Don on Moonstruck
Sabre 42 Hardtop Express & Blackfin 25 CC
When cruising life is simpler, but on a grander scale (author unknown)
http://moonstruckblog.wordpress.com/
Moonstruck is offline   Reply With Quote
Old 03-27-2013, 10:31 PM   #822
Scraping Paint
 
City: -
Country: -
Join Date: Oct 2007
Posts: 13,748
The problem with the "twin twice as likely to suffer an engine shutdown as a single" theory is that this is the wrong formula.

The meaningful formula is that AN engine in a twin is just as likely to suffer an engine shutdown as THE engine in a single. Which is why I know plenty of people who have been boating for decades in twin engine boats and have never had to shut an engine down due to a problem, and at the same time I know people who had been boating for two seasons in a brand new single engine boat (Nordic Tug) and had already experienced two engine shutowns and come home on the end of a rope. Twice.

And of course the whole theory is blown out the window when one starts taking into account the age, condition, operation and service practices attached to each engine. A well-maintained, properly operated engine in a twin engine boat is far less likely to suffer an engine shutdown that a poorly maintained, abused engine in a single-engine boat.

So the actual reality is, the number of engines in one's boat has absolutely no bearing whatsoever on that person's likelihood of experiencing an engine shutdown because there are far too many variables that affect the reliability of every engine in every boat.

I have a 40-plus year old, twin engine boat and in the 14 years we've owned it we have never had a driveline failure. Nothing's broken, we haven't hit anything, nothing.

Mark bought a brand new single engine boat and within what, a year? his driveline fell apart into a zillion pieces.

So much for the "two is twice as likely to experience a failure as one" theory. If everything was identical across the board in every boat--- same engines, same drivelines, same maintenance, same operating procedures--- perhaps the "twice as likely" theory would hold a degree of water. But given the total inequality between boats, engines, and owner practices, there is no way to make a blanket statement like that.

So as psneeld said, every boater should get the number of engines they want or are comfortable having and for whatever reason they want. Redundancy, speed, easier engine access, or like me a person simply likes running as many engines at the same time that they can, all these reasons and more are valid.

The one thing a boater should NOT base a decision on in my opinion is the "two is twice as likely to experience a shutdown as one" theory because in the real world, it's simply not true.
__________________

Marin is offline   Reply With Quote
Old 03-27-2013, 10:41 PM   #823
Master and Commander
 
markpierce's Avatar
 
City: Vallejo CA
Country: USA
Vessel Name: Carquinez Coot
Vessel Model: 2011 Seahorse Marine Coot hull #6
Join Date: Sep 2010
Posts: 10,265
Quote:
Originally Posted by Marin View Post
The one thing a boater should NOT base a decision on in my opinion is the "two is twice as likely to experience a shutdown as one" theory because in the real world, it's simply not true.
Sorry, Marin. That's not logical. If one has twenty (whatever) engines, eventually there will be twenty (whatever) failures. With one engine, only one failure.
__________________
Kar-KEEN-ez Koot
markpierce is offline   Reply With Quote
Old 03-27-2013, 10:45 PM   #824
Master and Commander
 
markpierce's Avatar
 
City: Vallejo CA
Country: USA
Vessel Name: Carquinez Coot
Vessel Model: 2011 Seahorse Marine Coot hull #6
Join Date: Sep 2010
Posts: 10,265
Quote:
Originally Posted by Marin View Post

Mark bought a brand new single engine boat and within what, a year? his driveline fell apart into a zillion pieces.
Yeah, but since we blessed the boat, that happened in the berth.



__________________
Kar-KEEN-ez Koot
markpierce is offline   Reply With Quote
Old 03-27-2013, 11:12 PM   #825
Scraping Paint
 
City: -
Country: -
Join Date: Oct 2007
Posts: 13,748
Quote:
Originally Posted by markpierce View Post
Sorry, Marin. That's not logical. If one has twenty (whatever) engines, eventually there will be twenty (whatever) failures. With one engine, only one failure.
I don't argue that but it doesn't reflect reality. Define "eventually" in terms a boat buyer will find meaningful.
Marin is offline   Reply With Quote
Old 03-27-2013, 11:46 PM   #826
Art
Guru
 
Art's Avatar
 
City: SF Bay Area
Country: USA
Vessel Model: Tollycraft 34' Tri Cabin
Join Date: Feb 2011
Posts: 7,980
Reality is any engine can/could/might/may break down... or not!

Single screw engine breaks down = No Mo Power / Tow In!

Twin screw one engine breaks sdown = Plenty Mo Power / Motor In!

Twin screw both engines break down = New Mechanic From Then On!! LOL

Art is offline   Reply With Quote
Old 03-28-2013, 12:05 AM   #827
Guru
 
BruceK's Avatar
 
Join Date: Oct 2011
Posts: 7,570
Quote:
Originally Posted by markpierce View Post
Sorry, Marin. That's not logical. If one has twenty (whatever) engines, eventually there will be twenty (whatever) failures. With one engine, only one failure.
Not sure that advances the issue. For present purposes, try this summary:
If you have twins, lose one, you almost certainly still have one; if you have a single, lose one,you unarguably have none. It`s why a member fried his single FL by not closing it down, as he would have if he had two.
How long will it take all 20(or whatever) to fail?
I`m sure if anyone trawls the previous 800+posts, this and probably everything else,is covered, more than once.
Just saw Art`s contemporaneous post. Spot on!
__________________
BruceK
Island Gypsy 36 Europa "Doriana"
Sydney Australia
BruceK is offline   Reply With Quote
Old 03-28-2013, 12:11 AM   #828
Master and Commander
 
markpierce's Avatar
 
City: Vallejo CA
Country: USA
Vessel Name: Carquinez Coot
Vessel Model: 2011 Seahorse Marine Coot hull #6
Join Date: Sep 2010
Posts: 10,265
Me thinks you want the ability to exceed hull speed with multiple engines and transform your boat from a trawler to a sedan cruiser.
__________________
Kar-KEEN-ez Koot
markpierce is offline   Reply With Quote
Old 03-28-2013, 12:38 AM   #829
Guru
 
BruceK's Avatar
 
Join Date: Oct 2011
Posts: 7,570
Quote:
Originally Posted by markpierce View Post
Me thinks you want the ability to exceed hull speed with multiple engines and transform your boat from a trawler to a sedan cruiser.
Not so, we`re strictly a hull speed "plodder" but figure the handling and "get home" capability is worth the cost of twins. I had a single, never had a failure, but concede a single will likely get more carefully (? fanatically) maintained. And I don`t rule out ever owning a single again.
__________________
BruceK
Island Gypsy 36 Europa "Doriana"
Sydney Australia
BruceK is offline   Reply With Quote
Old 03-28-2013, 06:24 AM   #830
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,527
The meaningful formula is that AN engine in a twin is just as likely to suffer an engine shutdown as THE engine in a single.

IF the engines were properly sized , not installed on lowest purchase price by the builder , the single engine boat would have a larger , probably more robust selection.

The larger engines frequently come from more industrial sources,so can run at rated rpm and load.

Most of the smaller lighter auto or yard implement conversions are time limited at high power settings.

EG , run a Detroit at 2100/180HP its rating ,no problem.

IF used as a single the engine would have to use the same light loading , which reduces efficiency.

Run a Ford Econo-Power marinization at 135HP , not for long!

The overrated twins survive because they are usually operated at only a fraction of their advertised rating.

As a single the light duty engine would need to observe the same light load requirements , which harms efficiency.
FF is online now   Reply With Quote
Old 03-28-2013, 08:26 AM   #831
Guru
 
Moonstruck's Avatar
 
City: Hailing Port: Charleston, SC
Country: USA
Vessel Name: Moonstruck
Vessel Model: Sabre 42 Hardtop Express
Join Date: Nov 2008
Posts: 7,849
Now that my heart rate has calmed down, let's talk about realities. I had a single screw trawler for 6 years. It had two failures that required towing. One was a collapsed fuel line that caused the engine to starve for fuel. The other was a broken E clip (a 10 cent part) in the transmission causing it not to shift. In either case if I had twins I would have made it home under power. On my Blackfin with a single engine about 20 miles off shore a hydraulic steering line ruptured beyond repair at sea. The engine was fine but from torque steer the boat would just go in big circles. If I had twins I could have made it home steering with engine power.

I have had twins for many years, and never had to be towed back to the dock. I have lost an engine, but never two at once.

Would I buy another single screw? Depends on the boat, but I definitely would not rule it out. There are advantages to both.
__________________
Don on Moonstruck
Sabre 42 Hardtop Express & Blackfin 25 CC
When cruising life is simpler, but on a grander scale (author unknown)
http://moonstruckblog.wordpress.com/
Moonstruck is offline   Reply With Quote
Old 03-28-2013, 08:36 AM   #832
Enigma
 
RT Firefly's Avatar
 
City: Slicker?
Country: Bumpkin?
Join Date: Oct 2007
Posts: 9,996
Greetings,
Mr. jorge. "Depends on the boat, but I definitely would not rule it our. There are advantages to both."
And THAT is the ultimate, sole and decisive answer to your question!.....#832
__________________
RTF
RT Firefly is offline   Reply With Quote
Old 03-29-2013, 12:19 PM   #833
Guru
 
City: coos bay
Country: usa
Join Date: Oct 2012
Posts: 1,203
Quote:
Originally Posted by jorge View Post
Hi Guys
For the last 30 years I have being sailing on sailboats, and because I`m moving to Fort Myers where I have an apartment with a dock included, that only accept up to 5`0 draftI So I sold my 52 Amel Supermaramu. Now I`m looking to buy a power boat, trawler, or similar. Because I`m ignorant on this matter the first question is: One Engine or two engines.Y will be concentrated in the ICW, or Bahamas.I had in mine Mainship or Grand Banks type.
Any suggestion are really welcome.
hahahah....a single is better for fuel economy and maintenance costs but twins are very popular with many because of better maneuverability and alleged get home capabilities. Many singles have get home capabilities as well. In today's world of escalating fuel costs I like the single with get home option.
__________________
Britt
bfloyd4445 is offline   Reply With Quote
Old 03-29-2013, 01:26 PM   #834
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,712
".a single is better for fuel economy"


Floyd you should say "most think" as there are reasons that show that twins could be more efficient. Bigger props for example.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 03-29-2013, 02:01 PM   #835
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,903
Tired arguement...if properly set up...hard to imagine a twin would ever be as efficient as a single...ALL things being equal.

Every boat test where they tried it (and there's only been a few as it's almost never equal)...the single edged out the twins...find those tests you say?

Sure I can't.... otherwise I would post the link...but the articles by the top writers for all the yachtie mags or manufacturer's seem to think singles are slightly more efficient...AND all the other costs do add up over time owning twins.

Of course this is more of a theoretical discussion than what most people will encounter in reality...because finding 2 identical boats for sale, setup properly with exactly the same hp...etc...etc...good luck.
psneeld is online now   Reply With Quote
Old 03-29-2013, 02:28 PM   #836
Art
Guru
 
Art's Avatar
 
City: SF Bay Area
Country: USA
Vessel Model: Tollycraft 34' Tri Cabin
Join Date: Feb 2011
Posts: 7,980
Slam Dunk!

Single - most economical... more ways than one!

Twin - greater maneuverability/safety ... more ways than one!

Single boats are great!!

Twin boats are great!!

Each Captain to their own...

That's the answer... What's the question??
Art is offline   Reply With Quote
Old 03-29-2013, 02:53 PM   #837
Guru
 
SomeSailor's Avatar
 
City: Everett, WA
Vessel Name: Honey Badger
Vessel Model: 42' CHB Europa
Join Date: Oct 2011
Posts: 784
All I know is my dock neighbor... in his single FL120 45 came in after cracking the block because he "limped it home". I said said I would have shut it down and came in on one screw. He said "I wish I had that option...". I didn't realize he was a single.

I thought of this thread when he made that comment.
SomeSailor is offline   Reply With Quote
Old 03-29-2013, 03:08 PM   #838
Art
Guru
 
Art's Avatar
 
City: SF Bay Area
Country: USA
Vessel Model: Tollycraft 34' Tri Cabin
Join Date: Feb 2011
Posts: 7,980
Quote:
Originally Posted by SomeSailor View Post
All I know is my dock neighbor... in his single FL120 45 came in after cracking the block because he "limped it home". I said said I would have shut it down and came in on one screw. He said "I wish I had that option...". I didn't realize he was a single.

I thought of this thread when he made that comment.
Overheating crack the block, frozen coolant??
Art is offline   Reply With Quote
Old 03-29-2013, 03:10 PM   #839
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,712
Another reason a twin could be more efficient is that it's not having to counteract the propwalk w a deflected rudder creating more drag.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 03-29-2013, 03:30 PM   #840
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,903
Quote:
Originally Posted by manyboats View Post
Another reason a twin could be more efficient is that it's not having to counteract the propwalk w a deflected rudder creating more drag.

I move the rudder and so does the autopilot so much more that the teeny tiny bit of rudder necessary to overcome the almost non-existent prop walk AT SPEED , that you can't even realistically measure it...at least not on the dozens (maybe more) of sngle engine boats I have driven.
__________________

psneeld is online now   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 07:26 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012