1 vs 2 diesels, insights please..

[Cold Duck]

Really good thread, and some great wisdom. Although I have a single, as long as there would be room to work on a twin, I’m indifferent.

If I was going to be very remote for extended times, I’d carry more spares.

I’ve noticed lots of issues show some signs before getting significant and staying on top of everything, along with strict with maintenance is very helpful.

I’m happy with my choice for our type of cruising.

SPARES is another interesting topic. I worked on a lot of Fast Attack Subs back in the 70s and 80s. These guys go out for 3-6 months without support. Room for spares is at a premium. They actually fill up the companionways with food and eat their way down to the deck. So, a lot of thought goes into spares. Single Point Failure analysis is used to optimize what and how many spares to carry. Amazing what you can do if you have to in order to get home. Say halfway to Hawaii and engine blows a rod. You could actually remove the rod and piston and run the engine without one cylinder to get home. I've pulled a rod and piston while in the boat, not fun but it can be done.

 

[LN-RTP]

I read the whole thread today: As mentioned before, no right or wrong answer..
I had single and twin power boats as wells as 2 sailboats (twin engine really as the sails go up if the engine goes down and vice versa)
Also had numerous smaller boats, mostly center consoles, single and twins, 17' to 21'.
In addition got 3 years on commercial ships crossing big oceans, all single huge engines and have more than 2,000 hours flying single engine airplanes in harms way like bush Alaska and over the Bering Sea in commercial operations summer and winter.
Conclusion?
Same as everybody said above:
A well maintained single can be as "safe" as any twin, but less redundancy if anything goes wrong.
I sure as hell won't fly a single engine airplane over water in the Arctic any more, because I am older and wiser, but I will cruise a single engine boat from Florida to the Bahamas and back any day of the year without blinking an eye.

 

[slowgoesit]

I can't cite all the statistical analysis anymore but I can give a counterintuitive example of a similar situation. During WWII, a Corsair fighter squadron in the So Pacific wanted to improve their combat readiness. I can't remember the real numbers so I will just use numbers for illustration. Let's say at any given time 50% of the squadron was combat ready,15% were down for regular scheduled maintenance and 35% were down for unscheduled maintenance. The logical move would be to do more scheduled maintenance to improve the unscheduled maintenance numbers thus putting more planes online. But after analysis, it turns out most unscheduled maintenance occurred shortly after scheduled maintenance. When opening up a plane for inspection, it's easy to bend a this, pull a that, break or forget to put back a this. Today, commercial aircraft must go thru a maintenance cycle every 100 hours. Let's use that for example here. What they tried was lengthening the scheduled maintenance from 100 hours to 120hours. This put fewer planes at any time under scheduled maintenance and reduced the number of unscheduled maintenance over time thus putting something like 65% of the squadron online for combat vs 50%, simply by doing LESS maintenance! Going back to twins, statistically your maintenance will not just double when you double your engines and your MTBF (mean time between failure) will not go in half, but will actually increase. Many factors. I use to do all the numbers but getting old, now I just know the results LOL

Or just train your maintenance personnel better so they stop breaking stuff while doing scheduled maintenance . . . .

Your aviation maintenance/OR (Operational Readiness) rate, without any facts, is anecdotal, and not applicable to the discussion underway . . . . . IMHO.

 

[slowgoesit]

Slowgoesit, I am guessing with a Beebe design the boat has a controllable pitch propeller.

Yes

If I remember correctly, don't you have a variable pitch prop?

Yes

Rereading slowgoesits post, this makes sense. But prop walk should be considerably less noticeable in forward due to rudder wash overwhelming effect of prop walk.

Peter

And Yes again! Given the preference, we dock starboard side to, approach at a 30 -35 degree angle if possible, and back down, bringing the stern to starboard to the dock. We do have a bow thruster, but unless the tide/wind is being difficult, we generally don't use/need it.

And Sunchaser, that's cheating, as you know us and our boat! But thanks for the vote of confidence! Good thing you didn't observe us leaving James Island in the San Juans in the wee hours of a DARK morning . . . . on a lee shore . . . . with opposing current/wind . . . Did I mention it was DARK? But it'll buff out . . . . sort of. . ..

 

[NWboater2]

“I wonder what advantage the original owner had in mind? It was speed or safety IMO. I’m quite sure it was safety.

Another thing that could be the elephant in the room is social status. One gets a much stronger male image as in it takes much more courage to go down to the sea in a single.”

Huh…..I would bet that the vast majority of twin buyers (maybe not here) would rank speed first and maneuverability second. Safety? Oh yeah sure that’s good too.

The Twin 460 (!) yanmars on the last GB 42 ever built (for sale on yachtworld) aren't safer than the twin FL 120s the hull was designed for. Nor are they more maneuverable. They’re just a whole lot faster. Strong male image, tho. For some. Kinda silly to others.

 

[NWboater2]

Actually it’s 450 cats. https://www.yachtworld.com/yacht/2005-grand-banks-heritage-42-europa-8552065/

Pretty sure I saw one with yanmar 460s tho

 

[PierreR]

Yes

Yes



And Sunchaser, that's cheating, as you know us and our boat! But thanks for the vote of confidence! Good thing you didn't observe us leaving James Island in the San Juans in the wee hours of a DARK morning . . . . on a lee shore . . . . with opposing current/wind . . . Did I mention it was DARK? But it'll buff out . . . . sort of. . ..

I do miss the Sabb controllable pitch propeller I had on my last boat. Big savings in fuel.

 

[slowgoesit]

“
Another thing that could be the elephant in the room is social status. One gets a much stronger male image as in it takes much more courage to go down to the sea in a single.”

Maybe so, but the one time you get towed it, you lose ALL those cool points . . . . if there were any there to begin with that it . . . .


Seriously though, I couldn't care less about social status, one way or another. There's only one person I feel any need to try and impress, and she's been married to me for 34 years!

 

[backinblue]

Maybe so, but the one time you get towed it, you lose ALL those cool points . . . . if there were any there to begin with that it . . . .


Seriously though, I couldn't care less about social status, one way or another. There's only one person I feel any need to try and impress, and she's been married to me for 34 years!

Only 34? Rookie!

 

[Group9]

The one time we had an engine failure, on a twin engine boat, was on a St. Tropez going from Clearwater to Miami across the Okeechobee Canal. One of the engines threw a fan belt and I didn't have a spare on board. It's not like we would have died or anything on a single engine boat, but it was nice to be able to keep going. It handled fine in forward. But, trying to back it into the slip on one engine was one of most embarrassing days ever.

I've had a few single engine boat failures, but nothing I wasn't able to remedy pretty quickly. With the diesels, it was always just needing to change the fuel filter.