1 vs 2 diesels, insights please..

[mvweebles]

I'm glad I started with 2. Made the learning process easier. With more experience I can see advantages of one. It is a lot harder accessing accessing the hull side for service, but the low speed maneuvering capability is sweet.

With a single I would want a hydraulic bow thruster for sure.

FYI- learning to drive a single is not a bad learning curve. Not much more than a twin. It's different, and there are some maneuvers that are not easy, but 90% of the maneuvers are pretty straightforward. Few hours of practice for several days delivers remarkable competency. At least for 80% of the docking situations encountered.

Peter

 

[ofer]

. Luckily my wife is much smaller, so she fits in that space.
p.

if you have a small wife two engines are better

even with my single engine there are many times that i wish i had a small partner.

 

[Group9]

if you have a small wife two engines are better

even with my single engine there are many times that i wish i had a small partner.

You're not kidding. I'm 6'3" and 225, and sometimes I'll get claustrophobic when I'm working on the outboard side of my twin engines and I get hung for a second and can't move. I have visions of the boat sinking and I can't get loose, LOL!

 

[SteveK]

decades ago in my then marina a new owner of twin screws asked if I could help him as he was used to singles. Dual throttle, dual shifters can be overwhelming.

I wonder if some, not all that prefer singles because they cannot operate a twin in close quarters.

 

[Simi 60]

if you have a small wife two engines are better

even with my single engine there are many times that i wish i had a small partner.

ACME Inflatable midgets, every boat should have a couple of them

I'm a big guy, I have enough room all around our single 855 to be comfortably sitting on a milk crate when working on the lower half
Luxury.

 

[Comodave]

You're not kidding. I'm 6'3" and 225, and sometimes I'll get claustrophobic when I'm working on the outboard side of my twin engines and I get hung for a second and can't move. I have visions of the boat sinking and I can't get loose, LOL!

Many years ago we were rehabbing a 30’ cruiser. It was in Tucson so it was hot. I went in under the dinette hull liner to work on a through hull. I had both hands extended over my head and my belt got caught on a screw. I couldn’t reach back to unhook it. My wife was at work and the boat was on a vacant lot with nobody nearby. I knew she wouldn’t even start to miss me until late that night and by then I would have died from heat stroks since it was going to be 110 degrees that day. I finally just gave it everything I could and ripped my belt loose from the screw, left a hunk of flesh on the screw but I got out. Scared the crap out of me. Ever since when I need to crawl into a small space I don’t do it unless there is somebody with me to at least dial 911…

 

[ofer]

Scared the crap out of me. Ever since when I need to crawl into a small space I don’t do it unless there is somebody with me to at least dial 911…

according to the latest discussions this qualifies for PTSD

 

[hmason]

Whenever I go into the engine room I have my cell phone with me. It won’t cover every eventuality but it should cover most.

 

[Comodave]

Whenever I go into the engine room I have my cell phone with me. It won’t cover every eventuality but it should most.

It won’t help when both of your hands are trapped above your head…

 

[RT Firefly]

Greetings,
Mr. hm. Make sure you have your shoes on, as well...

 

[Portage_Bay]

Many years ago we were rehabbing a 30’ cruiser. It was in Tucson so it was hot. I went in under the dinette hull liner to work on a through hull. I had both hands extended over my head and my belt got caught on a screw. I couldn’t reach back to unhook it. My wife was at work and the boat was on a vacant lot with nobody nearby. I knew she wouldn’t even start to miss me until late that night and by then I would have died from heat stroks since it was going to be 110 degrees that day. I finally just gave it everything I could and ripped my belt loose from the screw, left a hunk of flesh on the screw but I got out. Scared the crap out of me. Ever since when I need to crawl into a small space I don’t do it unless there is somebody with me to at least dial 911…

I too have learned that lesson the hard way. Now I call a trusted friend, tell them if they don't hear from me within an hour or what ever time I need to call a number I give them. That will cover getting stuck but won't cover injury or other emergency.

 

[Greg QS]

For me its twins. Better close quarter maneuvering, redundancy, Higher power for high current situations.

 

[Mambo42]

You're not kidding. I'm 6'3" and 225, and sometimes I'll get claustrophobic when I'm working on the outboard side of my twin engines and I get hung for a second and can't move. I have visions of the boat sinking and I can't get loose, LOL!

Working on the StBd engine is a nightmare for me, often get cramps in my legs after a couple of minutes in an impossible position, hurts like hell. But by now she knows the StBd engine is her department, i will explain her what to do.

 

[Mac2]

"QUESTION: I'm leaning towards twin diesels for redundancy, safety - all the talking points from the twin engine crowd - that is comforting to me. That said, i really lean in and listen to the single engine trawlers group that say it's no necessary due to sea tows, cell /satellite services and so on. "The only thing that stops these diesels is bad fuel."

Bad fuel stops singles and twins. I've had both. I prefer my twins only because I have a huge engine room to work on them and both shafts/props are protected. On my single engine boat, I made it as bullet proof as I could. Fuel polishing system, bypass oil filter, alarms on raw water intake, oil pressure, exhaust temp. engine temp etc. I installed this myself. Not that hard. Not that expensive, and it made life a lot less stressful while cruising. In the PNW a protected prop and shaft (typically on a single engine) would be the priority for me.

 

[omoore]

Single v Twin

The long-range commercial fishermen who make their living at sea have single engines. I'm referring to the those who fish off South America and the King crabbers of the Bering Straights who risk death with an engine failure. On the yachting side, Bruce Kessler and his Zopilote , a Delta 70, made numerous trips to Alaska and Mexico and circumnavigated on a single engine--a commercial grade Cat whch was the engine of choice of the U.S. shrimping fleet back in the day.

The majority of Nordhaven yachts are single screw. It is safe to estimate that more Nordhavens have made long offshore passages than any other builder.

Twins give people a sense of safety and, of course, easy maneuverability.
Steve Dashew, the legendary offshore voyager and designer of the innovative "functional power boat", chose twin power. But it is important to note that Wind Horse, his first boat, was an 80-footer with twin 150 hp engines. By contrast my GB 42 has twin 120's and is over-powered.

More important to me for offshore voyaging is stability. Dashew points out that "the majority of powerboats, from launches to large tankers, would not survive a roll past 60 to 70 degrees" His boats can roll to 135. But they are unique. In shopping for a passagemaker I would look for the boat with the lowest center of gravity.

From experience, I agree with Dashew and Nordhaven that the rudders are too small on many, if not most, production boats which are not really designed for offshore passages despite the verbiage in the glossy brochures.
Bottom line: I would opt for commercial rated single diesel and a bow thruster.

 

[sunchaser]

OM

Either singles or twins are fine for most of us. Unless you're doing a new build the choices come down to a lot more than single Vs twin. A few clarifications to your post --

As you likely know, single power Nordhavns and FPBs have robust get home engines with separate drive trains. A decade ago I was in NZ contemplating an FPB 64. The first few were singles only, but converted to a get home system with the FPBs after that being "twins" via the get home.

Many Nordhavns have been built with identical twins the latest being the complete. run of N41s. Having been on a few single power commercial vessels, I'm quite impressed with the spare parts allowing for very serious repairs at sea and the skills to know how to do the work. Plus lots of work space!

 

[psneeld]

Convenience...... twins can be more convenient. Get home engines are just a form of differential twin.

Everything else has been argued with no solud answer such as using thrusters, towing, costs of where broken down versus moving in a boat with higher regular but smaller maintenance costs than if broken down in the wro g place/time.

So convenience becomes preference based on cruising style mixed with budget and cruising area.⁷....in my covoluted way of explaining the root decision.

 

[Phyrcooler]

OM
—snip—

As you likely know, single power Nordhavns and FPBs have robust get home engines with separate drive trains. A decade ago I was in NZ contemplating an FPB 64. The first few were singles only, but converted to a get home system with the FPBs after that being "twins" via the get home.

Many Nordhavns have been built with identical twins the latest being the complete. run of N41s. Having been on a few single power commercial vessels, I'm quite impressed with the spare parts allowing for very serious repairs at sea and the skills to know how to do the work. Plus lots of work space!

I’m curious if any of the Nordhavn crowd has any info on the number of times the “get home” has been actually NEEDED to actually get home? Was it used just while a repair was being made to the main? How many have ever had a catastrophic enough of an event with their main that they had zero options without the “get home”?

I’m firmly in the “Single with thrusters” camp for the majority of my envisioned cruising. Until you’re in serious blue water beyond any expectation of tow. Then I’m more of a sail guy at that point anyway.

 

[MVDarlin]

I have twins. Essential when a crab pot fouls your wheel or you ding a prop on a rock especially in remote areas of Mexico or Alaska. The engine is not the only essential part of your running gear.

 

[Circumnavigator]

This discussion is similar to the old Ford vs Chevrolet arguments.


I'm a single screw guy. We go strange and wonderful places that are not always well charted and a single with a skeg is much better protected than twins. An encounter with a large log can wipe out both sides of a twin while the same encounter would go under the propeller of a single. Both Fintry (pic to the left) and our new-to-us Morning Light are singles. We crossed the Atlantic on Fintry and have put 4,000 miles on Morning Light in the two seasons we have owned her.


I can put either of them exactly where I want her and turn them in their own length with or without the bow thruster. That takes practice, but isn't actually hard to learn. A good boat handler can do the same with a twin.


As noted above, a single will have more space in the engine room. That isn't an issue on Fintry -- her engine room is 20x20' -- but on boats in the 35-60' range it can be hard to work on the outboard sides of twins.


Range is important to us -- we spend a lot of time in Canada, where they add a US$1.50 a gallon tax, so we like to have all our fuel aboard when we go there. Twins use more fuel at the same speed and the extra weight and size of the second engine usually means that there are smaller tanks in a twin.


I have had an engine failure that couldn't be fixed on board only once -- fifty years ago the crankshaft broke in two on a Perkins 4-106 that had just been rebuilt by a top name yard. That's in 50 years and around 50,000 miles.


Jim

 

[SteveK]

This discussion is similar to the old Ford vs Chevrolet arguments.
I'm a single screw guy.

Well since I am a Chev guy with twin screws, you must like Fords.

 

[Delta Riverat]

My twin screws and short rudders are also skeg protected;

 

[slowgoesit]

Delta Riverrat,

I hate to disagree, but IMHO, from the provided pic, Neither the propellers OR the rudders on that boat are skeg protected. IE; if you were to hit a log that you ran up on, with the log rolling along perpendicular to the vessels direction of travel, it would roll along from the turn of the hull, and off the skeg, and it will hit your prop, and possibly the rudder on that side as well, as demonstrated by the line of the hoisting straps. It goes almost through the center of the propeller. Granted, it would only trash ONE prop, but it most likely would not protect you from running over a log. If I'm interpreting the photo incorrectly, don't hesitate to point out my errors . . .

My twin screws and short rudders are also skeg protected;

 

[Comodave]

Our last boat was twins with a keel similar to the one photoed above. Coming up the Hudson River very early in the season we hit submerged objects at least 12 times, some that caused the whole boat to shudder. I figured we had toasted the props but when we hauled there wasn’t a mark on them. The keel protected them completely. The keel extended about 5” below the props. So the twin props not being protected isn’t always true.

 

[ranger58sb]

I think the issue that I'd be concerned about most is maintaining steerage, or at least being able to keep the boat pointed into weather.

I'd usually prefer a single (If the rest of the boat fits and I had a choice), but don't know that drogues or sea anchors in open water would solve the weather issue if the engine shut down.

-Chris

 

[gulfstar3659]

Hello one or two engines ?
Two engines one dieseltank benefit is less
Sailing in shallow waters , most 1 engine boats have better prop protection
When sailing near to side of small and shallow canal etc one engine is better prop in the middle ! Has more space before making contact
1 engine is easy to maintaine 2 double as much work and cost
1 engine gives much more space around especially when you have to do it yoursel and are somewhat older and a bit overweight
1 engine is gives tou more range with the same dieseltanks

This said i am glad i have 2 engines (Gulfstar 36 trawler 1974 mark 1) perkins 85 hp each , never had problems but it is a better feeling , but had 4 boats before with one engine never where afraid than , keep your diesel clean and have double filers etc.

 

[koliver]

My twin screws and short rudders are also skeg protected;

I think the reality is somewhere between the statement by Riverat and Scot's analysis.
My running gear is protected by a keel that is deeper than Riverat's, but the props and rudders still protrude beyond that straight line connecting the bottom of the keel and the chine. I have run over a telephone pole size log, hitting it while my line of travel was perpendicular to its resting position in the trough, and hitting closer to the middle of the log than to an end. That hit, at 7 - 7.5 knots, pushed down on the log, enough to ride over it for the full length of my keel, but the log never touched my chine. The outboard end of the log may have been out of the water, but wherever it was, the line it took was low enough to clear my rudder on that side, and the prop only took a light hit. My boat speed as the end of the keel passed the log was sufficient to clear the log before its floatation elevated it to the height of the bottom of the exposed rudder.
I conclude from this that the keel does provide a lot of protection, more if you can hit closer to the middle of a long log, less as your point of impact approaches either end.

Hitting a log in conditions where the sun is in your eyes, the troughs are at right angles to you, logs are frequent hazards, does a lot to improve your awareness and vigilance, and especially your choice of alternate directions to avoid those conditions. My encounter, described above, has kept me free of similar encounters since that occurred, some 25 years ago.

 

[La Sirena]

I have a Selene with a single (450 hp diesel) & get home engine (54 hp diesel). The get home engine does provide some redundancy, but it's not perfect. First, I can only get 4 kts on the get home. In bad weather it would probably just keep the boat pointed into the waves. Also, you have to run it every month or so to keep it in working order. The boat tends to veer to port when I do because the get home engine is on the stbd side, and the main propeller creates some drag in the center (even though it does freewheel). Also, another set of running gear to maintain.

The get home engine is much smaller than a second main engine, and much easier and cheaper to maintain. Also, single engine boats (with or without a get home engine) get slightly better fuel economy. The main shaft and screw are very well protected behind a large keel and rudder shoe.

Don't overlook Selenes if you're considering a KK or N.

 

[Simi 60]

Love the protection our setup provides

 

[Delta Riverat]

That's almost bullet proof!