Twin Diesels versus single

[Skag]

Great thread. I've got to put my vote in for a single and the prop protection it inherently provides when on a trawler with a full keel. However, as many others have said:
1) It must get perfect maintenance
2) Have all critical spares on board
3) The captain must know the engine intimately and how to quickly repair it
4) Good clean fuel - with a means to circulate and clean the tanks

In addition to the basics above, I require and have for my peace of mind:
5) Dry-stacked exhaust and keel cooled. This removes the sea water and main heat exchanger completely at a cost of sacrificing some internal space. This also means zero salt water running through anything in the engine room.
6) Mechanical, proven reliable engine that is run at a fraction of it's rated HP. My current is a 3306 Caterpillar (run at only 1,100rpms...), prior was a 6BT cummins (no salt water aftercooler, run at 1,600 rpms).
7) Spares to the extreme: entire fuel injection pump, starter, injection lines, injectors, fittings, full engine gasket set, all belts (x2) hydraulic/fuel hoses and fittings (to make my own custom hoses on the fly), heat exchangers (engine and trans oil), turbo charger, replacement filters (6+ of each), engine water pump, belts, alternator(s), hydraulic pump, power steering pump, steering hydraulic rams, steering hydraulic solenoid valves, enough fluids to replace at least 2x. I'm sure I missed something. My boat is full of spares - at 105,000 lbs I don't care about the extra weight. Spares are wrapped in oil impregnated paper to prevent corrosion, wrapped in bubble wrap and logged in a spreadsheet identifying location stored. If I had to buy these again, I would find a used engine and pull all of the parts - I likely have $10K+ in spares. I had always carried a spare prop as well - until I saw the price to replace the current large four blade I have on my 50' trawler.
8) Engine fuel shutoff - must be either mechanical lever or an "energize to shut down" solenoid. It baffles me why most diesels use "energize to run" solenoids. I've converted every diesel boat to mechanical or "energize to shut down" after I almost hit the breakwall when my engine decided to shut down (Cummins 6BT) due to some corrosion on an electrical connection. Very risky to have "energize to run" system with salt water ......... only a matter of time.
9) I do all of my own maintenance to make sure I know the engine well. It also helps immensely with saving $$
10) Engine alarms and automatic shutdowns. All the basic gauges + alarms + automatic shutdowns. When out of the harbor and on autopilot, I arm a shutdown system that can be triggered by low oil pressure, low oil level, high coolant temp or low coolant level. In close quarters or in the harbor, with a flip of a switch the shutdown system is dis-armed.
11) Tools - enough to tackle any repair. Including a welder. All critical specialty service tools for the engine.

I don't like to worry....

 

[VanBrudenship]

Thread getting a bit old, but here it goes. I just got my first twin screw boat. The learning curve is easy. The manuverability especially with a bit of a breeze is just amazing. Put it where you want without banging off the docks. Yes, it will burn a bit more fuel but the control, IMO is worth it. Also, the currents in many places can be strong and if one goes out you are good but on a single you better be ready to drop anchor in those places. All that said, there are some high HP downeast boats with bow thruster that I'd probably consider when I move up.

 

[Mac2]

Great thread. I've got to put my vote in for a single and the prop protection it inherently provides when on a trawler with a full keel. However, as many others have said:
1) It must get perfect maintenance
2) Have all critical spares on board
3) The captain must know the engine intimately and how to quickly repair it
4) Good clean fuel - with a means to circulate and clean the tanks

In addition to the basics above, I require and have for my peace of mind:
5) Dry-stacked exhaust and keel cooled. This removes the sea water and main heat exchanger completely at a cost of sacrificing some internal space. This also means zero salt water running through anything in the engine room.
6) Mechanical, proven reliable engine that is run at a fraction of it's rated HP. My current is a 3306 Caterpillar (run at only 1,100rpms...), prior was a 6BT cummins (no salt water aftercooler, run at 1,600 rpms).
7) Spares to the extreme: entire fuel injection pump, starter, injection lines, injectors, fittings, full engine gasket set, all belts (x2) hydraulic/fuel hoses and fittings (to make my own custom hoses on the fly), heat exchangers (engine and trans oil), turbo charger, replacement filters (6+ of each), engine water pump, belts, alternator(s), hydraulic pump, power steering pump, steering hydraulic rams, steering hydraulic solenoid valves, enough fluids to replace at least 2x. I'm sure I missed something. My boat is full of spares - at 105,000 lbs I don't care about the extra weight. Spares are wrapped in oil impregnated paper to prevent corrosion, wrapped in bubble wrap and logged in a spreadsheet identifying location stored. If I had to buy these again, I would find a used engine and pull all of the parts - I likely have $10K+ in spares. I had always carried a spare prop as well - until I saw the price to replace the current large four blade I have on my 50' trawler.
8) Engine fuel shutoff - must be either mechanical lever or an "energize to shut down" solenoid. It baffles me why most diesels use "energize to run" solenoids. I've converted every diesel boat to mechanical or "energize to shut down" after I almost hit the breakwall when my engine decided to shut down (Cummins 6BT) due to some corrosion on an electrical connection. Very risky to have "energize to run" system with salt water ......... only a matter of time.
9) I do all of my own maintenance to make sure I know the engine well. It also helps immensely with saving $$
10) Engine alarms and automatic shutdowns. All the basic gauges + alarms + automatic shutdowns. When out of the harbor and on autopilot, I arm a shutdown system that can be triggered by low oil pressure, low oil level, high coolant temp or low coolant level. In close quarters or in the harbor, with a flip of a switch the shutdown system is dis-armed.
11) Tools - enough to tackle any repair. Including a welder. All critical specialty service tools for the engine.

I don't like to worry....
View attachment 159521View attachment 159522View attachment 159523

Sooooo….you do have two engines

 

[sneal4600]

Thread getting a bit old, but here it goes. I just got my first twin screw boat. The learning curve is easy. The manuverability especially with a bit of a breeze is just amazing. Put it where you want without banging off the docks. Yes, it will burn a bit more fuel but the control, IMO is worth it. Also, the currents in many places can be strong and if one goes out you are good but on a single you better be ready to drop anchor in those places. All that said, there are some high HP downeast boats with bow thruster that I'd probably consider when I move up.

I will be getting to know a twin set up on my DF44 next May. Hopefully it is as short of a learning curve as you describe.

 

[Skag]

Sooooo….you do have two engines

LOL. Guilty. Some assembly required. I suppose if I take it up to the Aleutian Islands I’d even get a cylinder head and piston kits. I could always limp into an anchorage and make myself at home for a week. lol. I’m an engine junkie. The only thing that would stop me from not coming back is a rod coming through the block - with a properly maintained 3306 is not really credible.

 

[VanBrudenship]

@sneal4600 Just remember one thing, the inward curve of the throttles is where the boat will go. If you put each throttle with each hand, and put your thumbs inwards that shows where the boat will move.

Port throttle forward moves the bow Starboard. Port throttle backwards moves the stern Starboard. And Visa Versa. The boat will move forward more as its naturally designed to do so.

Don't touch the throttles. Stand backwards when backing in and use the GEARS behind your back.

Movementum is your friend; as long as you are not going faster than you are willing to hit something in your way.

And if you are coming from a single, it will be a piece of cake, a really good crab cake......

 

[SteveK]

@sneal4600 .............................

Don't touch the throttles. Stand backwards when backing in and use the throttles behind your back.

In practise for those seasoned and familiar with their boat may execute flawlessly, but as a general advice it is inviting problems.

 

[VanBrudenship]

In practise for those seasoned and familiar with their boat may execute flawlessly, but as a general advice it is inviting problems.

I am not a seasoned yacht captain, I've run my new to me 32' twin for about 10 days total. Standing backwards provides a better view. Watching momentuem of the boat is key here, IMO, and turning around over and over was not helping me, it was actually confusing me. Standing facing backwards really helped me backing in.

So perhaps people just need to try and see what works best for them.

 

[psneeld]

I have plenty of time running all kinds of twins as a commercial/marina captain, lived aboard a 37 flybridge sportfish for 5 years, owned it another 2 and the only time I stood backwards was once or twice to see if it was different or even any good.

Standing sideways was good enough for me...I could then have perspective in both directions and never really needed to turn all the way around as the controls don't move, usually my hands never left them, and the wheel at that point wasn't used much. So that worked for me and yes, people should adjust to see what worked best for them...

It works best from what I can tell, if on a sportfish that you can see the transom well. For some/many trawlers where you really can't see the cockpit/transom, not sure the view when turned around is "better". Without cameras, the best mate in the world with 2-way comms or if one is good enough to wander around the flybridge for a better view..... you are docking blind.

Never saw the need and saw plenty of captains that did drive backwards become unaware of what was going on in front of them.

Really didn't suit most of the students I had until they were very comfortable with their boats....even then... most had all different style driving positions. Some take forever or never learn and give up, some become OK at docking a twin, some get very good at it but at very varying speeds.

A lot depends on whether an instructor is needed and how good they are if they are needed.

 

[Mako]

@sneal4600
Don't touch the throttles. Stand backwards when backing in and use the throttles behind your back

Personally I never liked this technique, but try it for yourself and see if it helps.

However, I believe you meant to say “use the gears behind your back”

 

[rslifkin]

I've never been a fan of standing backwards either. I tend to stand either forward or sideways when backing in depending on what's around us. Realistically, in many cases I'm more worried about what's next to us or where the bow is swinging than what's directly behind the boat (glances back there are fine, I don't need to watch it constantly).

 

[psneeld]

Just like pilots. truckers, heavy equipment operators I know.... at least most I know have all told me that they felt they arrived as an operator when they see the space and equipment in which they are operating.... in their minds eye...and place the equipment where they want it but always checking and backing up that mental picture with all their sensory updates they can.

Just a "better" visual from a "stance" can be hampered by everything from distractions to optical illusions that can put the boat/other things in danger.

Every time I dock and I always encourage those I am coaching or teaching, to think as fast as they can about all the things they are doing and what is going on and what is physically around them. They look at me and ask "shouldn't I concentrate on what I am doing" and I say sure.... but the more one absorbs the tid bits around them...the more that mental picture grows and becomes clearer.

No, I doubt andyone can do dock well with their eyes closed, but when "it" happens, one can tell how far many parts of their boat are away from objects without even looking in that direction.

 

[VanBrudenship]

Yes, I meant standing facing the stern with hands in back of me on the GEARS. This is on the Flybridge looking down. Checking sides and forward but always stepping back in the same position. This is what I do, it makes it easier for ME, maybe not others.

Didn't meant to stir up anything. I've run all types of equipment and vehicles. Vision and seeing where I am going is of high importance to me, maybe not everyone else out there.

I was talking only of when backing into a slip. Oh, and I "learned" this watching a couple captains of big sportfish boats.

I should have included the caviat that this is what works for me and not to be taken as best practice. My free advice is worth every penny just please don't ask for your money back...

 

[mvweebles]

So perhaps people just need to try and see what works best for them.

That makes perfect sense. A dock neighbor with a 40-foot fin-keeled sailboat used to back it into his slip (most boats in San Francisco go bow-first, so this was unusual). At the head of the fairway, he'd turn the boat around and drive it backwards by standing behind the binnacle so he was facing in the direction of travel which was backwards. He was a good helmsman - as odd as it seemed to see a boat traveling backwards with the helmsman standing behind the wheel, it worked really well.

Personally I never liked this technique, but try it for yourself and see if it helps.

However, I believe you meant to say “use the gears behind your back”

Mako - 'gears' (vs throttles) was my thought too. I move around a lot when docking a boat to see sightlines so this technique doesn't work for me either. Step to one side or the other to see what crew is doing, towards the back to see where the stern is, etc. There's nothing that says you can't leave the helm when docking (assumes you're moving predictably and slowly).

Peter

 

[SteveK]

A dock neighbor with a 40-foot fin-keeled sailboat used to back it into his slip (most boats in San Francisco go bow-first, so this was unusual). At the head of the fairway, he'd turn the boat around and drive it backwards by standing behind the binnacle so he was facing in the direction of travel which was backwards. He was a good helmsman - as odd as it seemed to see a boat traveling backwards with the helmsman standing behind the wheel, it worked really well.

A sailboat has the advatage of a rudder that will move the boat where you want it to go under power. (engine or sail)

After a sailboat race we were celebrating our win so the crew was up for sailing the boat into our slip backwards without engine. The Captain facing aft behind the wheel. The boat came to a complete stop beside our dock before anyone stepped off to tie up. It was a great crew.

 

[psneeld]

After seeing some of those "big sportfish cowboys" crash multimillion dollar boats and knowing how little they retained from my USCG captain classes even after only a year from graduation.... not sure I would use but a few as role models.

Like those Chesapeake docking rodeos.... yes those guys are pretty good at what they do...but I really don't think that's how most of us prefer to dock our vessels.

Boat handling is a very personal thing and what works on one boat doesn't always work for the next.

The best trait any captain can have is being adaptive and not settling on "how to do something" but rather understanding what is going on with the vessel in their command in each and every situation.

 

[ksanders]

...

Best success in your deliberations. Best piece of advice I can give is it's not about the boat, it's about the adventure. Don't over think the boat.

Peter

Peter that is great advice that dreamers should take to heart.

Focus less on the boat and more on preparing for cruising life.

 

[BruceK]

It varies on the day, but I sometimes stand outside the cabin via the stbd helm door reaching in to use the gears. It`s a stbd finger tie.
For reversing into the slip/pen, before you start steering with the gears, get the boat moving backwards. Brief simultaneous selection of reverse gears does that.

 

[ranger58sb]

After seeing some of those "big sportfish cowboys" crash multimillion dollar boats and knowing how little they retained from my USCG captain classes even after only a year from graduation.... not sure I would use but a few as role models.

Like those Chesapeake docking rodeos.... yes those guys are pretty good at what they do...but I really don't think that's how most of us prefer to dock our vessels.

Boat handling is a very personal thing and what works on one boat doesn't always work for the next.

The best trait any captain can have is being adaptive and not settling on "how to do something" but rather understanding what is going on with the vessel in their command in each and every situation.

Yep.

When we've been in a marina during the White Marlin Open with competitors all round, we never actually saw a crash... but we've heard of them. Fast approach looks great when it works, boatloads o' $$$$$$$$ when it doesn't.

And the Chesapeake docking competitions are mostly old deadrise boats with sometimes huge engines, no cares about leaning against piles or crashing the stern into the pier... Who would notice any damage? Last I heard, one of the current champions is a 13-year-old kid.

But we've seen the "stand backwards" thing, usually on a bridge where the controls don't give the operator much room to "stand beside" or "stand behind."

On our current ride and the just previous, I could turn backwards while facing the dock and stand on the other side of (forward of) the gear levers... so no need to manipulate gears/throttles behind my back. The previous boat had separate mechanical gear and throttle controls, easy to just use gears... but when a bit of throttle was actually called for, I couldn't reach easily, had to momentarily alter my position/stance. The current boat has electronic combo/gear/throttle levers, and the basic FWD/N/REV positions are very close together; THAT took some getting used to. Needs more concentration to remember which lever is where, so as to NOT use throttle inadvertently.

-Chris

 

[ranger58sb]

On the "how many engines" topic...

I could go either way, noting though that we're not gonna cross any oceans on anything smaller than one of the Star Clipper ships...

I see it as more than just engine choices (numbers thereof), though; more like trade-offs between engines (how many) and something else.

Single, often better prop protection, but deeper draft. Twins, props more exposed, but shallower draft. (Our current is twins, with prop pockets, even slightly shallower draft than standard twins.)

Single, often better engine room access for maintenance. Twins, often more cramped, often access to outboard sides more difficult. (Our current is not only twins, but V-configuration with outboard fuel tanks, so outboard engine access needs a small, lithe child... and center aisle access needs a shoulders and hips dance to get from one end to the other).

Single, I'd carry more complete spares. Twins, we carry some.

Et cetera.

FWW, I don't much care about fuel consumption differences. Even better is twins are smaller than two of whatever the single might have been. Fuel not particularly noticeable at trawler speeds, even with our 1800 HP. (Maybe we only use 14.7 HP each engine -- or some such -- when in trawler mode?)

Bottom line for us, we're more about the "whole boat" concept. How do living spaces accommodate our preferences? How does layout and systems installation allow (or prevent) easy maintenance?

And I might pay attention to WHICH engines, not just their population. I dunno this world very much, but for example I might want to compare Ford Lehman versus Perkins whatever versus Volvo whatever... and decide for whatever reasons that I might prefer one over another. In our world, another example is that I'd very likely prefer inline MAN I6 (800-ish HP) diesels over our current MAN V-8 CRMs (900 HP) or Cummins QRMs. Or in slightly smaller boats, Cummins 450s over similar Volvo or Yanmar diesels, maybe over some of the Cats too. All that would come after homing in on boats that come close to meeting all of out other criteria. After all, all that other criteria is what would usually make us prefer Boat A over Boat B...

If I were spec'ing something "perfect" I think I'd still prefer flybridge boats, but with both upper and lower helm... so the upper could be more open to weather... with easily managed clear polycarbonate panels at the forward end, no AC/heat required... because there's a lower helm. One fewer AC to maintain. Note that doesn't have much to do with how many engines.

If a single, bother bow and stern thrusters sound nifty. We don't use our bow thruster much for getting alongside or into a slip. More often just to move the Admiral close enough to a pile so she can get a line around it. Or to sometimes soften an alongside landing when wind and current are pushing us into the dock. Another factor that doesn't really have much to do with how many engines.

In a much earlier post, @Hippocampus mentioned the idea of a single diesel with EV backup, and two gens, one for household systems, one for household systems plus back-up propulsion. Sounds nifty to me. But then there'd also be that trade-off between engine location, drive gear protection, and draft... and so forth.

-Chris

 

[VanBrudenship]

I'd add the "big sportfish captains" I watched were not cowboy-like at all. They came in slow and controlled, they backed in perfectly. I was impressed and wanted to emulate that.

I just can't imagine it is a common occurance of "Cowboy" Sportfish Captains smashing up boats all over the country.

 

[VanBrudenship]

I used to ride snowmobiles with a English guy who used to captain big oil tankers mostly from Alaska to California but also all over the world, he later became a consultant. Being in control and able to anticipate were his two big themes.

 

[Mountain man]

How many out here in Trawler Land ,have used single engines ? I know everyone is going to say two for redundancy in the middle of the ocean. However I would like to know if there are any brave and adventurous souls that have done it. I will be going from South Carolina to Bahamas and further parts south. Please feel free to unload on me .

We run a single cummins in our boat Lucille. Never had a problem with a single. I pay strict attention to primary and secondary fuel filters. A bad load of fule or fouling of filters will shut down any diesel.
There have been times when I would have prefered a twin but only for maneuvering. We have a bow thruster which helps a lot.
Up sides are reduced maintance cost and reduced spair parts inventory.

 

[Mako]

More often just to move the Admiral close enough to a pile so she can get a line around it. Or to sometimes soften an alongside landing when wind and current are pushing us into the dock.

Wow that’s really cruel Chris. You use your wife as a fender to soften the crash landing???

 

[ranger58sb]

Wow that’s really cruel Chris. You use your wife as a fender to soften the crash landing???

Har, har! After re-reading.... ya got me there!

For the record, we do own and use real fenders from time to time, too.

-Chris

 

[Cargile]

...................................... We'll resume our journey this October with stops in El Salvador, Nicuragua and Panama before transiting the canal and eventually to Florida.................

Well, What happened? Have enjoyed your previous posts about your south of the border passage.

 

[mvweebles]

Well, What happened? Have enjoyed your previous posts about your south of the border passage.

Hurricanes Helen and Milton happened. Our home is in Madeira Beach and we got 3-feet of water in our house. Frankly, we'd be done with repairs by know except the municipal permitting process is totally constipated. They are more concerned with ticking every FEMA requirement so the towns can get reimbursed then they are about getting residents back in their homes. Very frustrating. Right now there is no timeline.

Glad you've enjoyed the storyline so far. We are both eager to resume. Hopefully sometime after the first of the year and we can make it to at least Panama (1000 miles south of where we are).

Peter