New Long Thin, Hyper-Efficient Trawler

As a multihull fan I know the key to low wake (low power to move) is light weight and a LB ratio of at least 5-1 with 6-1 being more accepted as the true minimum.

So a 40 ft boat would be 8ft beam on the WL, with 6.6 being even better.

This interior volume would mean a couple could cruise easily , with an other person or two , just for an ocean passage.

4 on 4 off gets old really fast, but 3 on 6 off is a Love Boat ride.

A 4th person could be cook, or just stand down for a day in rotation..

The key would be the same as any sail boat that operates short handed.
All normal operations need to be done by one person or at a watch change.

Reefing, or shifting head sails is the drill on the wind boats , launching or retrieving flopper stoppers would be the most effort on a power boat.

Only real hassles I can see would be the LAW in small towns , 12K would hardly cause a wake in NO WAKE zones , but would look fast to the guy with the badge and the 45 Magnum.

makobuilders said:

So what sorta savings are we really talking about? What percent less horsepower is required to push an ultra skinny boat (like those discussed, or a Dashew) versus a "normal" cruiser??

Click to expand...

It's impossible to compare "ultra skinny" with "normal" unless you define the vessels in some way. Weight (displacement) is one way to do it. If everything else is similar, equipment, finish, construction material, etc, the skinny boat will be lighter as it's physically smaller. So you can look at HP(thus fuel) required for different displacements on a given waterline at fixed speed.

Here's one comparison table from Jay Benford.....note that with a 50' waterline the 20,000 pound boat requires 38HP for 10 knots, the 30,000 pound boat 60HP, and the 40,000 pound boat 85HP. If one US gallon makes 18HP/hr, that's 2.11, 3.33, and 4.72 gph. So, as a general rule, twice the weight on the same waterline will require two and a quarter times the fuel for the same speed.



Here's a more elaborate table showing HP required for various stern forms and weights. Again these are general references and there will be variations in real life.



And really I think it's silly to compare a Dashew FPB 64 with a Nordhavn 64 strictly on fuel consumption basis. There are so many far more important differences, fuel consumption pales into insignificance. Yes speed and motion are different, but more importantly the arrangement and the actual amount of living space is completely different.

LRC58Fan said:

Here is a summary image comparing Nordhavn vs. Dashew FPB:

Source: SetSail» Blog Archive » Fuel Burn, Range, and Margin For Error

Click to expand...

Obviously trying to compare two boats of different displacement is skewing the results. So let's try to compare on a more equal basis: Two boats, same length, same displacement, same cruising speed, but different beams. The "trawler" model would have a length:beam ratio of about 3.5:1 and the "skinny" model would be about 5:1 or even 6:1. Drafts and underwater shapes between the two would obviously vary.

So how would power requirements be influenced due to the more easily driven hull?

Makobuilders,
You can't take length and high aspect ratio out of the picture as that's what is being compared.

And w same disp and same length one would have wild differences in their PC. As in full at the ends like a barge or skinny at both ends like an extreme sailboat. Why compare that?

But I would think the skinny ends would require less power and have less speed and the full end boat more speed and drag. I think the full ends would make the wave longer and give it more speed but making waves takes power. Consider the original boat that was round.

If one wants to race around the globe in record the FPB or similar long skinny boats make total sense. If one wants to go cruise and have all the comforts of home in a livable package the Nordhavn makes sense. Personally the FBP boats are not my cup of tea ( I have made that obvious in the past).. but they have their place. While a FPB 64 and a N64 are both boats, both 64' and both float.. the similarities stop there.

The volume cube ( living space ) in the fat trawler is massive in comparison.. which to me makes living aboard more comfortable.

We spend most of our time outside in warm climates.. the outside amenities of the fat trawler with a flybridge vs the outside of the FPB .. or other LSB ( long skinny boats) are huge.

There are a lot of factors that make the perfect cruising livaboard.

HOLLYWOOD

makobuilders said:

Obviously trying to compare two boats of different displacement is skewing the results. So let's try to compare on a more equal basis: Two boats, same length, same displacement, same cruising speed, but different beams. The "trawler" model would have a length:beam ratio of about 3.5:1 and the "skinny" model would be about 5:1 or even 6:1. Drafts and underwater shapes between the two would obviously vary.

So how would power requirements be influenced due to the more easily driven hull?

Click to expand...

It doesn't work that way. You can't just change one feature (beam) without affecting the rest of the system. Everything is dependent on everything else. Depending on which (the skinny or the fat) hull is the parent "Correctly shaped", the other will be horribly distorted. Not only will no one design or build such a boat, but no one has even bothered to test such a thing because in light of what we know about naval architecture, it's not worth bothering with.

This is why the Nordhavn 64 weighs over twice what the FPB 64 does, has 3' more beam, and twice the installed HP to get a slower top speed. Waterline length may be roughly similar, and fuel capacity is the same, but nothing else is.

LRC58Fan said:

I'm not familiar with Auxiliary Sailboats, but Sailboats as a class are a very common option - and well proven for distance cruising/blue water passage making. And I've read that something like 4,000 to 5,000 people a year do this.

But from my perspective (and I'm sure many also on this forum) the sailboat is not ideal. While I love sailboats and have owned a number of them for local cruising, my issues with sailboat for longer cruising are:

1. You feel like you're in a tunnel if you're inside the cabin - I like lots of glass so I can view the amazing outdoors, when I'm cooking, and relaxing inside the boat.
2. You're usually exposed to the weather - being forced to hang out at the back of the boat in the elements all the time (or most of the time) is sub-optimal for me.
3. The sailboat is difficult to manage as you get older - my parents, and many others eventually sell the boat (much like Steve Dashew has done) when they get older because they can't handle them.
4. A sailboat, by its very nature, is actually a "Hybrid" solution - with all the complexity of both sails and an engine. More complexity means more potential problems when long distance cruising.
5. A big part of the time you're probably under power, even on a sailboat. But you're dragging around a huge ballast and large sails that make it a less efficient powerboat than something like the Dashew FPB or Artnautical 58.
6. I'd like to take my parents on the boat - but with something that is frequently sailing at a large angle - it makes it very hard and dangerous for older people that have trouble walking and standing up.
7. Even the sailboats with the hard dodger that get you out of the elements when you are sailing - wall you off from the rest of the activity in the boat - so you're alone battling the elements. I would much prefer to be in a larger cabin with my family when cruising in bad weather.
8. Sailboats can't take a direct route to where you want to go - you have to follow the winds - which in my mind is suboptimal.

Click to expand...

Perhaps we could examine your list more carefully.
"1. You feel like you're in a tunnel if you're inside the cabin - I like lots of glass so I can view the amazing outdoors, when I'm cooking, and relaxing inside the boat.
2. You're usually exposed to the weather - being forced to hang out at the back of the boat in the elements all the time (or most of the time) is sub-optimal for me.
7. Even the sailboats with the hard dodger that get you out of the elements when you are sailing - wall you off from the rest of the activity in the boat - so you're alone battling the elements. I would much prefer to be in a larger cabin with my family when cruising in bad weather."

There are large pilothouse sailboats and motorsailors that allow you to spend time in areas that are well lit, allow you to pilot, and enjoy the outdoors in much the same way as you would on a power boat.

"4. A sailboat, by its very nature, is actually a "Hybrid" solution - with all the complexity of both sails and an engine. More complexity means more potential problems when long distance cruising."

You could also count this as an advantage. Not counting fuel expenses, the advantage of having a better motion at sea and a get-home system counts for a lot.

"5. A big part of the time you're probably under power, even on a sailboat. But you're dragging around a huge ballast and large sails that make it a less efficient powerboat than something like the Dashew FPB or Artnautical 58."

Yes, but if you used the sails on beam reaches and off the wind, you would easily make up for this discrepancy in fuel consumption.

"6. I'd like to take my parents on the boat - but with something that is frequently sailing at a large angle - it makes it very hard and dangerous for older people that have trouble walking and standing up."

It's called a heeling angle. But you wouldn't have to sail with your parents aboard, you still have an engine.

"8. Sailboats can't take a direct route to where you want to go - you have to follow the winds - which in my mind is suboptimal."

Check out Richard's thread aboard Dauntless, and you will see he couldn't go directly where he wanted to. He was forced to go in directions that were much like tacking a sailboat because the motion of the boat was too much to handle for him (and maybe for the boat as well.) Have you ever experienced the snap roll of a powerboat in beam seas? What about rolling in following seas? Or continuous pitching into head-on seas? Do you really think you would be comfortable with that hour after hour, days after day sipping champagne in your main saloon with your elderly parents? There is a reason most sailboats have their cockpits in the stern and not on the bow or amidships. Ocean crossings are often uncomfortable and I dare say MUCH less comfortable on a powerboat than a sailboat.

There is a reason ocean crossings are generally done on sailboats and NOT powerboats and it has nothing to do with fuel costs.

Tad Roberts said:

It doesn't work that way. You can't just change one feature (beam) without affecting the rest of the system. Everything is dependent on everything else. Depending on which (the skinny or the fat) hull is the parent "Correctly shaped", the other will be horribly distorted. Not only will no one design or build such a boat, but no one has even bothered to test such a thing because in light of what we know about naval architecture, it's not worth bothering with.

This is why the Nordhavn 64 weighs over twice what the FPB 64 does, has 3' more beam, and twice the installed HP to get a slower top speed. Waterline length may be roughly similar, and fuel capacity is the same, but nothing else is.

Click to expand...

This thread has been a very interesting discussion. It would seem that a long, skinny boat goes hand-in-hand with lighter displacement. For guys like me that prefer steel and believe that heavy is the way to go, then that provides challenges. For guys like the original poster, or Dashew fans, who like aluminum then there are advantages to long, skinny.

However I have to pay $15 per ft for moorage and many marinas I've been to are tough to get into if you are over 40ft. When I owned my 65 footer with 50amp power requirement (versus the usual 30amp) I found cruising between marinas very difficult. For those of us without big wallets, there are practical choices to be made.

>It would seem that a long, skinny boat goes hand-in-hand with lighter displacement.<

Only if speed is a huge consideration , the slender boat (even in concrete at 15lbs a sq fr) will be a far better sea boat in terms of motion , and ride and cost less to push thru the water..


>However I have to pay $15 per ft for moorage and many marinas I've been to are tough to get into if you are over 40ft.<

That is why 3 story Beach Ball boats were invented , great value in a slip.

What you save in slip fees will purchase lots of diesel, just dont expect to see any Blue Water passages, or be comfortable underway over 15K of breeze.

Lots of choices !

New Super Efficient Long Range Trawler / Cruiser

bligh said:

Perhaps we could examine your list more carefully.
"
7. Even the sailboats with the hard dodger that get you out of the elements when you are sailing - wall you off from the rest of the activity in the boat - so you're alone battling the elements. I would much prefer to be in a larger cabin with my family when cruising in bad weather."

There are large pilothouse sailboats and motorsailors that allow you to spend time in areas that are well lit, allow you to pilot, and enjoy the outdoors in much the same way as you would on a power boat.

Click to expand...

YES - I know of many motorsailers that have somewhat large pilot houses - but I tend to agree with Steve Dashew on this point - that its nice to have the kitchen in the same level (the upper level) so that everyone is at the same level most of the time when the boat is traveling - to keep the community together and not make the pilot feel like he's / she's working alone so much of the time.
I really like the design of the Dashew FBP in that respect - where everyone is in the "great room" (just as we are usually in the house /home with the kids) - with a great view of the outdoors. It just feels right from a social engagement perspective. Most of the motorsailers have smallish pilot houses - for a couple of people to hang out in but not for everyone to be there at the same time, and generally not when preparing meals - which takes a lot of the time on boats.

bligh said:

"4. A sailboat, by its very nature, is actually a "Hybrid" solution - with all the complexity of both sails and an engine. More complexity means more potential problems when long distance cruising."

You could also count this as an advantage. Not counting fuel expenses, the advantage of having a better motion at sea and a get-home system counts for a lot.

Click to expand...

Yes - but you're hauling a huge amount of ballast around the world with you to achieve that - and you can have a "get home" sail on your long thin powerboat too - that can be quite effective in those very rare situations when you need it.

bligh said:

"5. A big part of the time you're probably under power, even on a sailboat. But you're dragging around a huge ballast and large sails that make it a less efficient powerboat than something like the Dashew FPB or Artnautical 58."

Yes, but if you used the sails on beam reaches and off the wind, you would easily make up for this discrepancy in fuel consumption.

Click to expand...

Perhaps - but it all depends on your cruising destinations and the wind/ tacking that actually takes place.

bligh said:

"6. I'd like to take my parents on the boat - but with something that is frequently sailing at a large angle - it makes it very hard and dangerous for older people that have trouble walking and standing up."

It's called a heeling angle. But you wouldn't have to sail with your parents aboard, you still have an engine.

Click to expand...

Yes - but you still have the many stairs of the sailboat, the issue with most people being either downstairs in the "hold"/cabin, or outside in the elements - which isn't ideal for the older parents.

bligh said:

"8. Sailboats can't take a direct route to where you want to go - you have to follow the winds - which in my mind is suboptimal."

Check out Richard's thread aboard Dauntless, and you will see he couldn't go directly where he wanted to. He was forced to go in directions that were much like tacking a sailboat because the motion of the boat was too much to handle for him (and maybe for the boat as well.) .

Click to expand...

Yes - I've followed Richard's thread about his trip in Dauntless - and I see that as simply an issue with the Trawler design - that makes the boat pitch a lot in significant seas. (rather than go through the waves as with a longer, thinner design).

As one person said above " the slender boat (even in concrete at 15lbs a sq fr) will be a far better sea boat in terms of motion , and ride and cost less to push thru the water.."

The Trawler design is really design-optimized around carrying a large amount of stuff (for example, "Fish"), not for seakeeping/comfort when passagemaking. Its also not optimized for longer distance efficiency. This is another reason I like the longer-thinner designs of these new boats like the Dashew FPB and Artnautica LRC 58.

Here's what the big boys are doing. Scale it down and move on.

Palmer Johnson

Long Thin Hyper-efficient Trawler - Artnautica 58

Definitely a beautiful boat (IMHO) - but not sure if the design would work for a long distance cruiser designed for safety and low cost of maintenance. It seems like the sponson design leaves the boat open for catastrophic failure if they hit a log or container in the middle of the ocean.



And of course - this design is expensive as hell, I suspect. I'd love to hear from a boat designer though. It does seem like a way to balance the two design considerations of the benefits of the long-thin design, with the greater space benefits of the traditional trawler boats.

Would love to hear Tad Robert's opinions on this type of design and its pros and cons.

skidgear said:

Here's what the big boys are doing. Scale it down and move on.

Palmer Johnson

Click to expand...

Hyper-Efficient Long Range Trawler

Does anyone here have experience cruising at higher latitudes?

Can you share with me what type of insulation you have on your boat to keep it warm (or cool, in hotter areas)?

This new boat that was the topic of the discussion initially has the following insulation . Do you think this is enough insulation?

"The silver foil covered stuff ... is a self adhesive 5mm thick foam that keeps the condensation at bay. Additionally I will have 100mm of polyester will with an R-value of 2.5 to further help keep things toasty/cool."

Click to expand...

Forget insulation just get a Dickinson oil stove. Open the windows when it's too hot.

Higher latitudes No, all winter , even with floating chunk ice , you bet.

Unless the boat would be a special custom build the thickness of insulation takes loads of room , and many are combustible , so must be covered with flame proof material.R-7 can be had , but might hold water and become useless. On our RV after the rebuild we went with the blue foam, not a hifg R factor but handles water best of all the foams. In 1/4 sheets it can be layered to fill every space.

The windows are usually R-0 , just keep out the breeze , and even with shrink outside and inside the R value still sucks.

Do the best you can and have and (as was suggested) a number of sources of heat that require only fuel and gravity.

Worst case would be 5-10 GPD just for heat for your voyage plus engine and noisemaker fuel.

Our 33ft MS with 3/4 Airex (some insulation value ) would gobble 4 GPD thru a Dickinsom when the temps go down to -10F.

Bronze window frames would show white frost from breathing.

Thanks FF,

I've just read on the Morgan's Cloud Blog (a expedition sailboater's blog) that the Boreal ( a well-known aluminum expedition sailboat) has 3 inches of insulation above the water line. Seems like for the Artnautica to be similarly equipped you'd have to have a little bit of design work done.

Boreal 44, (RC Louise) and we only sail in warm waters. We purchased the Boreal because she is every bit as good in the tropics as in the high lats. Our plans for our Boreal are the Caroline Islands and the jungle rivers of Borneo, very hot and humid. The boat has about 3 inches on well done insulation, even the dog house is insulated she stays much cooler than the outside air at all times. We were concerned that the dog house would be hot in the tropics also but now know that the doghouse does not get very hot while on passage.

Click to expand...

Source: Comments section on:

Boreal 44 Expedition Aluminum Sailboat

Interesting New Long Thing Passagemaker by Bering

Another new longer, thinner (but much heavier in this case) passagemaker by Bering.



Details Here:

The Bering Steel Yacht 20

Also - new writeup on the Artnautica 58 here: A Real Sailor’s Motorboat Launched

Looks like a mini Steve Jobs boat, whatever it is called.

I guess I see some similarity between the Steve jobs boat and the Bering design - but still quite different:

Folks seem to think hauling a keel along is a waste.

The keel weight is almost the only way of having offshore ultimate stability , coming up right side after a 180 deg roll.

At SL of about 1 a ton of weight only requires about 2 or 3 hp per ton , so a 5 ton keel would cost under 1 GPH to tote along.

You pay for insurance , your heirs will thank you for ,
why not some righting ability as insurance , YOU can profit from?

What a beauty.
Oh no, someone else did it first

FF said:

Folks seem to think hauling a keel along is a waste.

The keel weight is almost the only way of having offshore ultimate stability , coming up right side after a 180 deg roll.

At SL of about 1 a ton of weight only requires about 2 or 3 hp per ton , so a 5 ton keel would cost under 1 GPH to tote along.

You pay for insurance , your heirs will thank you for ,
why not some righting ability as insurance , YOU can profit from?

Click to expand...

Long, thin boats like the Dashew FPB and Artnautica LRC 58 - have great ultimate stability and don't have to carry all that unnecessary weight.

Dashew does a great job of explaining the factors that affect stability in the real world in this article: SetSail » Blog Archive » Evaluating Stability and Capsize Risks For Yachts

More info here: SetSail and Long Range Cruiser 58: a fuel-efficient boat. - Dennis Harjamaa Yacht Design, Elegant Yachts, Aluminium, Fuel-Efficient, Sailing, Cruising Boats.

LRC58Fan said:

Long, thin boats like the Dashew FPB and Artnautica LRC 58 - have great ultimate stability and don't have to carry all that unnecessary weight.

Dashew does a great job of explaining the factors that affect stability in the real world in this article: SetSail » Blog Archive » Evaluating Stability and Capsize Risks For Yachts

More info here: SetSail and Long Range Cruiser 58: a fuel-efficient boat. - Dennis Harjamaa Yacht Design, Elegant Yachts, Aluminium, Fuel-Efficient, Sailing, Cruising Boats.

Click to expand...

For those of you too tired to read the above citations, I will be glad to quote them to you, in sum:

1. We know what we are doing; no one else does. We have no idea why they keep designing those death traps.

2. Just look at our graphs. We can also use Excel to prove that the Sun revolves around the Earth, but that is on a different website.

3. We do our boat designing at the center of the maritime world, Tucson Arizona.

Wxx3 said:

For those of you too tired to read the above citations, I will be glad to quote them to you, in sum:



1. We know what we are doing; no one else does. We have no idea why they keep designing those death traps.



2. Just look at our graphs. We can also use Excel to prove that the Sun revolves around the Earth, but that is on a different website.



3. We do our boat designing at the center of the maritime world, Tucson Arizona.

Click to expand...

Hit it dead center on the head!

Wxx3 said:

For those of you too tired to read the above citations, I will be glad to quote them to you, in sum:

1. We know what we are doing; no one else does. We have no idea why they keep designing those death traps.
...

Click to expand...

I'll make it simpler by just quoting the manufacturer stability measurements:

Dashew FPB: "Although the FPB 64 specifications call for 130 degrees this shows ultimate stability remains positive until 150 degrees."

Kadey Krogen 42 Stability: "Range of positive stability.....85 degrees"
Source: http://www.his.com/~vann/KrgStuff/krognfaq.txt

Which one would you rather cross oceans on?

LRC58Fan said:

I'll make it simpler by just quoting the manufacturer stability measurements:

Dashew FPB: "Although the FPB 64 specifications call for 130 degrees this shows ultimate stability remains positive until 150 degrees."

Kadey Krogen 42 Stability: "Range of positive stability.....85 degrees"
Source: http://www.his.com/~vann/KrgStuff/krognfaq.txt

Which one would you rather cross oceans on?

Click to expand...

If I had to choose one or the other, I'd go with the Kadey. However, personally I'd choose a bigger boat, but I would never choose the Dashew. That doesn't mean there is anything wrong with it. It just means it does not appeal to our tastes or desires at all. It would be nice if Dashew fans would present it as a different concept well executed rather than Dashew as a God. You don't have to put another boat down to build one up. And comparing a 42 to a 64? If you want stability, why not go Elling? They put on a nice little show. There are a lot of consideration in selection of a boat beyond the stability measurements. But I'm not a minimalist, would get claustrophobic trying to sleep on that boat. For many of the reasons I'd have no desire to cross in a sailboat, I wouldn't in a Dashew 64 either.

Think of this. If it was truly the be all end all perfection of boats, wouldn't there be a few thousand or at least a few hundred sold? And don't say he can't make that many. Easy to set up a factory. In reality there is no boat that is for everyone. The greatest selling boat out there has a minuscule total market share.

What we are seeing here is a return to the lite displacement/length type of boat(long and skinny). What is new is that the materials and building techniques are now available to make the lite part realistic. Builders down under and in Europe are trying to introduce production models along these lines. Some have already done some impressive sea miles. The secret is keeping it lite and that means Spartan interiors relative to the common summer cottage trawler types. As Tad has pointed out start adding junk and you ruin the whole concept.

eyschulman said:

What we are seeing here is a return to the lite displacement/length type of boat(long and skinny). What is new is that the materials and building techniques are now available to make the lite part realistic. Builders down under and in Europe are trying to introduce production models along these lines. Some have already done some impressive sea miles. The secret is keeping it lite and that means Spartan interiors relative to the common summer cottage trawler types. As Tad has pointed out start adding junk and you ruin the whole concept.

Click to expand...

One man's junk is another man's treasures. We like our junk. We like every electronic available, air conditioning, watermaker, generators. You name it.

One of your key phrases too is that "builders...are trying to introduce". So far not a lot of it sold. I hope it does develop for those who like it. But it's still got to prove itself viable in the market to do so.

LRC58Fan said:

Dashew FPB: "Although the FPB 64 specifications call for 130 degrees this shows ultimate stability remains positive until 150 degrees."

Kadey Krogen 42 Stability: "Range of positive stability.....85 degrees"
Source: http://www.his.com/~vann/KrgStuff/krognfaq.txt

Which one would you rather cross oceans on?

Click to expand...

Did you REALLY just compare a 2+ million dollar, brand new, purpose built passage maker boat to a 20+ year old $250-350,000 one that is over 20 feet shorter and not built specifically to cross oceans, although it obviously can???

Or are you trying to convince yourself Dashew and Artnautica make good boats?

If it is the former wow, just wow...

If the latter sign a purchase contract and have one built, I'd love to hear your impressions of cruising one. I might if the wherewithal and desire for a boat like it was in me. The only oceans I cross will be at well over 400 mph and 30+ thousand feet above them.