Tug compared to trawler as cruisers

[Cadence]

Originally Posted by Wckoek

Say for a owner operated yacht, we are limited to under 24m or 72 feet at the waterline and under 80 tonnes in displacement, regulation wise.
Beam and sq ft of living open, but ideally 3 cabin plus 2 berth for crew, a berth for watch keeping at pilot house.
Fin stabilizer is a must.
Maximum range above 5000 nautical miles.
The few boat I know that fit most of these criteria is Watson 60, it cost about 2 to 3 million to build I remember.

Most of us wanted to spend a little more,

[Wckoek]

Originally Posted by Cadence

Most of us wanted to spend a little more,

There is a little used one selling for 1.5 million, I can barely afford it if it's a million or a bit more, but then there are other factor to consider.
A Chuck Paine designed Kanter 62 is available for 600k, it is still not exactly what I wanted, very nice boat.
I don't know but motor yacht over 50 feet seemed to double or tripled over sailing yacht for the same size.
Maybe for a million it is more worthwhile to build a long sailing yacht like Beowulf or something like that, you can buy a lot of sails, fuel and hire crew with the savings.
A forty with 2 cabin something foot trawler yacht with range under 2,500 miles could be build well under half a million. This would have better fuel economy, economical to run but more basic amenities, still not quite enough for go anywhere boat.

[Cadence]

Originally Posted by Wckoek

There is a little used one selling for 1.5 million, I can barely afford it if it's a million or a bit more, but then there are other factor to consider.
A Chuck Paine designed Kanter 62 is available for 600k, it is still not exactly what I wanted, very nice boat.
I don't know but motor yacht over 50 feet seemed to double or tripled over sailing yacht for the same size.
Maybe for a million it is more worthwhile to build a long sailing yacht like Beowulf or something like that, you can buy a lot of sails, fuel and hire crew with the savings.
A forty with 2 cabin something foot trawler yacht with range under 2,500 miles could be build well under half a million. This would have better fuel economy, economical to run but more basic amenities, still not quite enough for go anywhere boat.

I'll run right out and get it out of the bank. I'm not sure people here or in that market? Obviously nor an I. I could afford some of them but being realistic not the up keep

[David M]

Originally Posted by Wckoek

Of topic really, I wondered if you have a view on which of the trawler type monohull displacement hull are fuel efficient? I mean non production designs and plans one can have it build by a yard.
LWL hull like those designed by Dashew is of course more efficient but they roll so terribly without stabilization and have much less carrying capacity for their given length.

Rounded hulls are most efficient. They provide the most amount of buoyancy for a given amount of wetted surface area. A perfect sphere provides the absolute most buoyancy for a given wetted surface area. So the closer a slow moving boat is to a sphere, the better but only in that respect. Obviously the boat must be streamlined as well...more like a fish.

At low speeds wetted surface area is where you get the most drag. Then comes wave making resistance. And then bottoms start to need to be flattened with vessels with a much higher power to displacement ratio so they can plane.

The reason cargo ships are squared off at the bottom is so they can get me maximum amount of cargo into a port given its bottom depths. They are also flat along the side because docks are as well...a compromise in keeping wetted surface area to a minimum.

Adding a hard chine and or a keel dampens rolling but then you are also increasing wetted surface area for a given displacement.

It's all a big compromise on what you want. There is no perfect boat nor a perfect answer.

[Wckoek]

Originally Posted by Cadence

I'll run right out and get it out of the bank. I'm not sure people here or in that market? Obviously nor an I. I could afford some of them but being realistic not the up keep

Yeah, over 50 feet or 30 tonnes for motor yacht or say over 65 feet or 35 tonne for sailing yacht seemed a different class is price and in maintenance although not quite at the super yacht level. Still, stabilizer and various system in a motor yacht cost a lot more and requirement more attention in maintenance than a sailing yacht with keel ballast and sails, even if the winches or anchor and various things are electric assisted.
A motor yacht will always roll more at high seas if you go offshore without active stabilizers and even with stabilizers they still aren't as stable as a deep lead keel.

Fuel hasn't been cheaper than now in many years, and it is cheaper to cruise under motor unless it is those fuel guzzling planing or semi planing yacht.
But as stated the true offshore motor yacht is much more expensive and complicated than say 40 footer for cruising and more than larger blue water sailboats still.

Maybe the Malcolm Tennant Globetrotter can be build cheaper and less complicated, I don't know. The trimaran Ghost is too small for extended cruising. I believe they can be build under a million maybe?
The Sunreef 70 I read can reach over 8000 miles, but cost more than 3 million.

[Wckoek]

Originally Posted by David M

Rounded hulls are most efficient. They provide the most amount of buoyancy for a given amount of wetted surface area. A perfect sphere provides the absolute most buoyancy for a given wetted surface area. So the closer a slow moving boat is to a sphere, the better but only in that respect. Obviously the boat must be streamlined as well...more like a fish.

At low speeds wetted surface area is where you get the most drag. Then comes wave making resistance. And then bottoms start to need to be flattened with vessels with a much higher power to displacement ratio so they can plane.

The reason cargo ships are squared off at the bottom is so they can get me maximum amount of cargo into a port given its bottom depths. They are also flat along the side because docks are as well...a compromise in keeping wetted surface area to a minimum.

Adding a hard chine and or a keel dampens rolling but then you are also increasing wetted surface area for a given displacement.

It's all a big compromise on what you want. There is no perfect boat nor a perfect answer.

Yes, there are development in wave piercing hull, but from my personal experience the not quite trimaran tunnel type of monohull is quite efficient also, with better load carrying capability and internal space.
Eco Marine Technologies | Home
I have experienced a unit build in China, with fuel economy up to 7mpg, good speed also, and requires less power to run, but it wasn't a blue water boat. I seemed to recall there is a larger design that utilize similar hull shape but don't remember the name of the boat.
Just don't know why it is not in much demand but people are willing to spend millions on fuel guzzling monsters that only have a range of couple hundred of miles.

[ZULU40]

Originally Posted by Wckoek

I have not seen designs or proposals of these type, does Adastra counts as one?

Agree with SWATH, and the only the stability yacht proposal I read wasn't that impressive, and even more complicated to build and maintain.

Still monohull trawler, as we earlier mention the cruising long range type is pretty hard to beat for fuel economy, space, carrying load and weight. Range regardless is still a tough nut to crack even with the advancement of fuel economy as it is difficult to find a balance between carrying capacity of fuel, weight, power, stability and a lot of things.

I have seen a tunnel semi-planing monohull capable of 7mpg, but it wasn't a bluewater long range design.

yes I think Adastra qualifies

I think we can assert that displacement multihulls will defeat monos for fuel economy. Remember its really about how much HP is required to drive at hull speed.

Kurt Hughes 38ft Trimaran Trawler (Kurt's nomenclature not mine)
''6.5 hp will push this tri at hull speed''
I calculate its fuel consumption to be 19.65 MPG at 8 knots (hull speed), and near 30MPG at 5 knots
Kurt Hughes Multihull Design - Catamarans and Trimarans for Cruising and Charter - 38' Trimaran Trawler

Roger Hill has within a list of designs, the use of 'displacement catamaran'
Roger Hill Yacht Design, Catamaran, Yacht, Powerboat, Naval Architect, Catamaran Design, Auckland, New Zealand

Schionning have within their portfolio 'semi displacement'
http://www.schionningdesigns.com.au/...mancePower.pdf

.

[Wckoek]

Originally Posted by ZULU40

yes I think Adastra qualifies

I think we can assert that displacement multihulls will defeat monos for fuel economy. Remember its really about how much HP is required to drive at hull speed.

Kurt Hughes 38ft Trimaran Trawler (Kurt's nomenclature not mine)
''6.5 hp will push this tri at hull speed''
I calculate its fuel consumption to be 19.65 MPG at 8 knots (hull speed), and near 30MPG at 5 knots
Kurt Hughes Multihull Design - Catamarans and Trimarans for Cruising and Charter - 38' Trimaran Trawler

Roger Hill has within a list of designs, the use of 'displacement catamaran'
Roger Hill Yacht Design, Catamaran, Yacht, Powerboat, Naval Architect, Catamaran Design, Auckland, New Zealand

Schionning have within their portfolio 'semi displacement'
http://www.schionningdesigns.com.au/...mancePower.pdf

.

The Kurt Hughes is a very basic coastal kind of cruiser.
But Roger Hill's design is more interesting, but I don't know if the 19.8m would carry a lot of fuel for longer range.
The 10.2m displacement cat would be less competitive to monohull of similar size.

The only motor cruiser yacht I read can do more than 5000 miles (ocean crossing even the pacific) on production is the Sunreef 70 multihull and Watson 60 and above monohull trawlers, maybe Bering 80 also.
The Dashew FPB can do this but have to rely on paravane on rolling.
All of them are complicated, and cost multi million, almost super yacht price.

Custom design wise, I see the Harjamaa Long Range Cruiser and Ghost Trimaran can do this with less cost, but not without drawbacks. Rolling for the LWL monohull and internal volume, carrying capacity for the trimaran.

[ZULU40]

Originally Posted by Wckoek

The 10.2m displacement cat would be less competitive to monohull of similar size.

this is where I stopped reading, (presume copyright to Boating NZ)

[Wckoek]

Originally Posted by ZULU40

this is where I stopped reading, (presume copyright to Boating NZ)

Yes, the Eco cruiser D37 can post equal numbers at hull speed, but it is a larger boat with even better range.
I believe Van De Stadt's Stadtline 38 can have equal or better fuel economy at hull speed if fitted with a smaller engine. Also a larger boat with good fuel economy.

[TrentePieds]

Quote: "...we are limited to under 24m or 72 feet at the waterline and under 80 tonnes in displacement, regulation wise."

Who is "we"? Who is doing the "regulating"? None of this is particularly relevant if the "yacht owner" happens to hold, say, an Extra-Mariner's qualification - essentially a PhD in seafaring.

Further to what Stumble has said: You can design for 1) High cargo carrying capacity, 2) High speed and 3) Operating economy. You can have any two. you CAN'T have all three.

The relevant laws of the universe forbid it :-)

TP

[Stumble]

Originally Posted by Wckoek

Say for a owner operated yacht, we are limited to under 24m or 72 feet at the waterline and under 80 tonnes in displacement, regulation wise.
Beam and sq ft of living open, but ideally 3 cabin plus 2 berth for crew, a berth for watch keeping at pilot house.
Fin stabilizer is a must.
Maximum range above 5000 nautical miles.
The few boat I know that fit most of these criteria is Watson 60, it cost about 2 to 3 million to build I remember.

Dashew FPB 64, or 70, or 78 depending on your preferences.

[Pelagic]

Originally Posted by Wckoek

I
In my country diesel only cost $2 USD per gallon, unless you travel like more than 10,000-15,000 miles per year it is far cheaper than the cost of maintaining sails and rigging per year and sailboats need an engine running too.

The problem with powered cruiser is always range, I don't see that much designs that can run more than say 3,500 miles on a single tank, unless it's those ultra expensive behemoth that carries 1,500 to 2,000 gallons of fuel and very expensive to run.

Interesting!
If I were choosing/comparing between power boat and sail (motor sail) I would shortlist the choice to an Ocean going Trawler and a offshore designed sailing Cat and weigh the pros and cons.

Both at the same price range of say around $650k and designed for comfortable live aboard for 4.

I have not priced and compared what you can buy, but it would be an interesting excercise.

1... Cabins... do I really want a grand cabin for owner or am I happy with one hull for myself?

2.... Range and redundancy... I think the sailing cat wins hands down for unlimited range and backup diesel engine for powering. Fuel cost is not the issue, but availability and quality is... If remote cruising

Also, the majority of diesel consumption is often from running generator at anchor, if not energy independent.

3..... Solar footprint favors the sailing cat to be energy independent

4.....Main salon and pilothouse...favors the trawler as does 'bale capacity' (storage)

5.....comfort at anchor.....sailing cat....

6.....underway dependent on point of sail but upwind favors trawler

What other comparisons should we consider?

Is that price range too low? Should it be higher?...
....your choice [emoji4]

[Stumble]

For a boat this size you really need to also include the cost of sails. A high efficiency motor yacht can very easily wind up cheaper to move than a sailboat. The cost of sails in the >65' range can be substantial, and their lifespan isn't all that long.

For a 70' monohull I would guess a 3di main is going to run around $100,000. $250k in sails would not be unexpected.

[Scout 30]

Originally Posted by boatpoker

When asked, we just tell folks our Benford 38 Fantail is a "trawler" for simplicity. In reality we just think it's a boat.

Back in the 20's boats like our Scout 30 were called raised deck motor cruisers. That works for me but when I tell people that I just get a perplexed look so we too just call our boat a trawler.