Semi-displacement Ocean Crossing

[bpgt3]

Hi everyone. Searched and found a few things but not exactly i guess.

Are there any semi displacement trawler brands that can safely cross oceans?

I understand the benefits of full displacement for long distance but can you cross oceans with a Fleming, Selene, etc by regulating speed? Can it sip fuel for long distances? Will a semi displacement hull sacrifice safety for speed?

I am a huge Nordhavn, Diesel Duck and Bering fan and want to make long passages when I finally purchase a boat capable of these crossings. I also realize that ocean crossings will be a relatively small amount of my boating life. The rest of the time I wouldn't mind going a little faster than 8 knots.
Thanks

 

[Shrew]

A semi-displacement passage maker is an oxymoron. Either their tankage is too small or their fuel burn rate too long to make transoceanic passages. Many can make smaller passages, such as to the Bahamas and Caribbean islands.

 

[rslifkin]

It can be done, but you'll be doing the crossing below hull speed to have enough range. And you generally need a pretty big SD boat to handle the weight of enough fuel. A couple of Flemings have crossed the Atlantic, for example, but there are not all that many SD boats capable of a run like that.

 

[Codger2]

" I also realize that ocean crossings will be a relatively small amount of my boating life. The rest of the time I wouldn't mind going a little faster than 8 knots."

You have just defined the boat's main mission! Stick with it and buy a hull that meets your speed wants.

 

[psneeld]

A lot depends on how you fine tune the question.


Go large enough and yes fast mega yachts do safely cross the ocean.


Then the question is... a boat not really made for it, carrying extra fuel...is it really doing it safely? Well more than a few do it and with today's weather forecasting...speed can be a virtue, not a problem.


No matter what answers you get, if you read long enough...you will see examples that are exceptions.... so all you have to do is fine tune the question to what you are willing to buy or chance.

 

[MYTraveler]

There are at least a few SD boats with the range to cross oceans. Being prone to seasickness, and being short on time (still working), I didn't buy my boat to cross oceans but instead wanted the ability to fish whereever along the east Pacific coast. I came close having a Nordhavn built, primarily because it offered the range I wanted, but in the end it really wasn't suitable for fishing. Instead, I opted for a Mikelson Nomad, a SD boat that I run at displacement speeds 95% of the time. She carries 2,300 gallons of fuel, and has the range (and stability, redundancy, etc.) to cross oceans if that is the goal.

 

[SteveK]

Cannot be that hard to cross the ocean, these guys did it in this trawler.

 

[ksanders]

Here is a thought many folks don't consider.

You can ship your boat across the ocean.

Lets say you wanted to explore europe.

A 50' boat can be shipped from Florida to Europe for around $30K last time checked.

That's not a lot of $$ in the overall scheme of things.

 

[bpgt3]

Thanks for all the replies.

There is some info on the Flemings being able to make ocean crossings while at displacement speeds. Think Tony Fleming did a bunch of years back.

I do realize many boats COULD do it. How safely is another story. Maybe I'm looking for something that doesn't exist yet.

 

[mvweebles]

A few months ago, a Hatt 65-ish in Gibraltar was trying to figure out how to get to North America. If they dialed back to 7 kts or so, they'd make it, and thought about deck fuel just in case.

Fuel management is a calculus problem for even displacement boats. The N40 that did the round the world run arrived in Hawaii from Dana Point with less than 50 gals of fuel on board. But at the halfway mark, they knew their burn and the weather so the cranked up the speed a bit.

20 yrs ago, passagemaker magazine ran an article of a guy with a GB42 that ran from California to Hawaii. He removed one prop and ran on one engine. Mid ocean, he jumps in and swaps props to run on the other engine to equalize hours. He was a single handed which is no surprise to me. Something wrong with a guy who'll do that.

It can be done, but you won't get much info on the web. You'll have to do your own research and have the courage of your convictions. Forums like this will tell you it can't/shouldn't be done.

Good luck.

Peter

 

[FWT]

https://www.passagemaker.com/lifestyle/the-ultimate-bluewater-challenge

 

[mvweebles]

Thanks for all the replies.

There is some info on the Flemings being able to make ocean crossings while at displacement speeds. Think Tony Fleming did a bunch of years back.

I do realize many boats COULD do it. How safely is another story. Maybe I'm looking for something that doesn't exist yet.

I recently read a sailing thread on worst weather ocean crossing sailors encountered. There were many tall tails, but one impressed me. A cruising couple well into their 80s and still living aboard their boat after 55 of cruising. She said that back in the day, you could pick the weather you departed in, but had to accept the weather you encountered. Weather forecasting has advanced a lot since then. Sobering advice.

Trips like these can be done relatively safely, but are not risk free. Wx forecasting are pretty decent for 3 days our, barely acceptable for 5 days. After that, it's a crap shot. But if you are picky about going in the best possible season and learn a bit about weather and when to follow a front, you can greatly reduce your chance of lousy weather.

I'd worry about weather, but not as much as mechanical issues and provisioning.

Bottom line, there are some SD boats that can cross an ocean, but not without taking precautions

Peter

 

[Jmarsh203]

I have an aluminum semi displacement 42 footer that has 1200 gallons of fuel with paravane stabilizers. My rough guess is at 7.5 kts I’ve got about a 4500nm range. I was planning on repowering with Cummins 6b 180hp engines. Again my rough guess on top speed with repower would be around 16kts fully loaded 18+ with less than half fuel and water with a range of slightly over 900nm using the Mac weight range and speed so it would be better. Now keep in mind my 42 foot boat has the interior space of a 36 footer so yes it can be done range wise but you will give it up somewhere else. Also and my walls and windows are strong enough for green water over the bow so I’d say safe enough, do need new doors though if I was going to make an ocean crossing. Needs weatherproof aluminum doors so she looks all uniform. My boat was built in 72 with a cost that could have bought 3 GB42s at the time. With less interior space than a gb36 so it’s no wonder they never sold well

 

[Jmarsh203]

I’ve got twin Ford Leighman 120s in her right now and she will do 11kts to the pins but they don’t like it. A non turbo Cummins 6b could run to the pins for days and wouldnt hurt them.

 

[SteveK]

I’ve got twin Ford Leighman 120s in her right now and she will do 11kts to the pins but they don’t like it. A non turbo Cummins 6b could run to the pins for days and wouldnt hurt them.

How were they saying they don't like it. I know the words may not sound right but you used them first.
I have had mine pinned and doing 13 knots and they sounded good, then of course they started to heat up, they did not like the continuous load, is this what you mean?

 

[Benthic2]

https://www.passagemaker.com/lifestyle/the-ultimate-bluewater-challenge

From that article.....

The current record speed now stands at 53 knots average, but the record holder, the Fincantieri Destriero—at 223 feet in length, with 60,000 horsepower on tap, and burning 10 tons of fuel per hour—is a far cry from her pioneering predecessors.

10 TONS OF FUEL PER HOUR !??!!?!!?!

 

[DDW]

I do realize many boats COULD do it. How safely is another story. Maybe I'm looking for something that doesn't exist yet.

I don't understand the obsession with SD vs FD. There is no inherent difference in safety between them. The way many are built and marketed, FD may tend to have better seaworthiness, due entirely to features independent of the hull form that most associate with one or the other. Things like AVS, downflooding angles, unsupported glass area, redundancy - these are the essence of seaworthiness, not chines. If you want an SD boat that will cross oceans as safely as any, there is no reason it cannot be built.

 

[Daddyo]

My DeFever 48 LRC is considered SD by some but when you take a closer look at her hull I’d say she’s FD. Either way she has transatlantic range and capability no doubt. I’d definitely add fish to keep the crew happy though.

 

[Daddyo]

I don't understand the obsession with SD vs FD. There is no inherent difference in safety between them. The way many are built and marketed, FD may tend to have better seaworthiness, due entirely to features independent of the hull form that most associate with one or the other. Things like AVS, downflooding angles, unsupported glass area, redundancy - these are the essence of seaworthiness, not chines. If you want an SD boat that will cross oceans as safely as any, there is no reason it cannot be built.

[emoji106]

 

[Nomad Willy]

There are at least a few SD boats with the range to cross oceans. Being prone to seasickness, and being short on time (still working), I didn't buy my boat to cross oceans but instead wanted the ability to fish whereever along the east Pacific coast. I came close having a Nordhavn built, primarily because it offered the range I wanted, but in the end it really wasn't suitable for fishing. Instead, I opted for a Mikelson Nomad, a SD boat that I run at displacement speeds 95% of the time. She carries 2,300 gallons of fuel, and has the range (and stability, redundancy, etc.) to cross oceans if that is the goal.

Thanks for all the replies.

There is some info on the Flemings being able to make ocean crossings while at displacement speeds. Think Tony Fleming did a bunch of years back.

I do realize many boats COULD do it. How safely is another story. Maybe I'm looking for something that doesn't exist yet.

Perhaps it does.
If you had a Planing hulled boat and built a duplicate that weighed about 1/2 as much it would burn half as much fuel.
This I don’t know but if you built a boat the same volume and 1/2 as much beam it would burn much less fuel .. but I don’t know how much.

Now I may be getting into the “not built yet” category. Most planing hulled boats are not really narrow.

The lowest fuel burning boat may be 1. Light. 2. Narrow. And 3. FD. You’d have all three things that play a major role in mpg efficiency.
BUT would you have a seaworthy enough boat?

And there may be other design features that would be lacking. Very narrow may limit interior space use-ability. In other words the boat may not be one you’d want or could use for ocean crossing.

 

[kapnd]

I’ve got twin Ford Leighman 120s in her right now and she will do 11kts to the pins but they don’t like it. A non turbo Cummins 6b could run to the pins for days and wouldnt hurt them.

Why do you specify non turbo Cummins 6B motors?
Cummins finds it expedient to turbocharge it’s smallest (180 hp) 6B marine motor.
I’m sure they put considerable time and effort into R&D to come up with that particular fuel map.
A non turbo model would be either modified, very old, or adapted from an origin other than marine rated, which is not a unit that I’d be comfortable doing ocean crossings with.

 

[MurrayM]

The Elling E6 is said to have transatlantic range.

https://www.ellingyachting.com/the-elling-motor-yacht-range/157727/elling-e6/

 

[Benthic2]

What are you guys so worried about ? This guy did it in a boat that was 5 feet 4 inches long!

 

[caltexflanc]

There are excellent discussions of this in Beebe's "Voyaging Under Power" and Gerr's "The Nature of Boats."

 

[MYTraveler]

I don't understand the obsession with SD vs FD. There is no inherent difference in safety between them.

To increase AVS, many vessels designed to cross oceans carry a great deal of lead ballast. Going faster than displacement speeds radically increases fuel consumption and horsepower requirements, even without that additional weight but adding that weight is a double whammy. So, designing a boat with the range and stability to cross an ocean generally means limiting the boat to displacement speeds, which eliminates the need for (and cost of) engines with enough horsepower to plane even a boat not heavily ballasted. Once the need for more than displacement speed is conceded, the efficiency of a FD hull, rather than an SD hull, makes sense. But I agree with you, I cannot imagine any reason why an FD hull form is inherently safer.

 

[Jmarsh203]

How were they saying they don't like it. I know the words may not sound right but you used them first.
I have had mine pinned and doing 13 knots and they sounded good, then of course they started to heat up, they did not like the continuous load, is this what you mean?

They will overheat during prolonged full throttle application but when I say they aren’t happy there it’s more than just that but hard to explain. while they do go to higher rpm the motor just doesn’t feel happy there, as opposed to something like a Detroit you can pin the low hp ones against there rev limiter and they seem happiest bouncing off the rev limiter all day long, I’d say it’s a harmonics thing but I have no proof to back that up, just something I feel from turning wrenches for a couple years. Combine that with a boat like mine even though it has the hypothetical hp and plenty of fuel for her to go faster for very prolonged legs because of engine constraints even if she wasn’t overheating I wouldn’t just pin them and run that way for 20 hours straight which the boat would be capable of doing. The weak link is the motors in my setup right now, and to top it off I know everyone loves the leighmans but honesty I am not a fan, they are high maintenance and service life is questionable in my opinion. Of the era the perkins 6.354 was a much better design with both the removable liners and better fuel pump setup so that was a full blown commercial engine that has a service life of in excess of 20000 hours for Tbo and the Cummins 6b in the non turbo variant is good for many more hours I’ve seen them in the 30,000 hour range between overhauls. So when people are happy for hitting 10-15,000 hours in a Ford Leighman I’m not super impressed. It’s a motor that saw very very limited usage in the commercial field even in its prime and that says a whole lot about the motor.

 

[Jmarsh203]

So the Cummins 6b came first not the 6bt, also there is no difference between the 6b and 6bt internally, same heads, cam, injectors, injector pump, crank, pistons, it was simply a non turbo motor that designed itself well for installing a turbo. Pretty much they threw on a new exhaust, intake and turbo with required piping and went with it. Turned out that was a big hit. Now why would I choose a NA motor over a turbo? Maintenance is a big one, no turbo means no turbo rebuild or replace, also never a chance of a turbo shattering and getting eaten by the motor. Also because I love the throttle range of where a non turbo motor can be happy, if I were trying to go faster and cruise in the upper limits the majority of the time the turbo motor would be the way to go obviously but the speed difference I would get from 80 extra hp going with the turbo motor would only give me like 1 maybe 1.5kt extra speed and to me that’s not worth the extra headaches. Also since I carry so much extra fuel the 2-5% extra efficiency I get from a turbo motor I don’t need.

 

[Nomad Willy]

DDW wrote;
“ I don't understand the obsession with SD vs FD. There is no inherent difference in safety between them. The way many are built and marketed, FD may tend to have better seaworthiness, due entirely to features independent of the hull form that most associate with one or the other. Things like AVS, downflooding angles, unsupported glass area, redundancy - these are the essence of seaworthiness, not chines. If you want an SD boat that will cross oceans as safely as any, there i
s no reason it cannot be built.”

[emoji106]

Daddyo’s emoji is a thumbs up.


Sure you can go to the grocery store in a school bus but it’ far from the best vehicle for that mission.

A FD hull is by far the best hull to have crossing oceans. The range, seaworthyness and favorable motion for crew is clearly only available in FD.

And that’s about the extent of it. Millions of people in this country drive to work or the store in an oversized PU truck. But it’s far from ideal. We do what we want to do. Within our means.

Crossing oceans can be done in SD hulled boats ... big ones. From a range point you can (to some degree) make up for that by taking other routes and more and better planing. Many or most can deal w the discomfort and general incompatible interior arrangements. But at night you almost need a dark pilot house w/o distraction of other people.

The answer to the OP’s question is yes, w a big enough boat. But it’s far from ideal. And hull form is indeed what FD is all about.

DDW, it’s about stability (already mentioned). Directional stab, roll stab, pitch stab and range range range and even comfort.

 

[psneeld]

And most people don't expect ocean crossing as the major use of their boat, it's a minor use.... one so a SD boat MAY be the best choice for a boat overall, just not the small percentage of ocean crossing time.


Assuming safety and relative comfort is clearly understood.

 

[Fletcher500]

I don't understand the obsession with SD vs FD. There is no inherent difference in safety between them. The way many are built and marketed, FD may tend to have better seaworthiness, due entirely to features independent of the hull form that most associate with one or the other. Things like AVS, downflooding angles, unsupported glass area, redundancy - these are the essence of seaworthiness, not chines. If you want an SD boat that will cross oceans as safely as any, there is no reason it cannot be built.

Agree, and what a lot of people don't realize is many hulls lie somewhere on the spectrum between FD and SD.