Nordhavn 56 MS

[tsr]

I stumbled onto this website a while back and have spent many an hour searching the archives for pearls of wisdom. As this is my first post, I thank you in advance for whatever responses are to follow.

I have not seen much discussion of the new Nordhavn 56 MS and what little mention I find tends to be rather negative, at least when compared to the ATOA 64. I readily admit my relative ignorance in matters of design when compared with many on this board. As I have politely drooled over this latest Nordhavn model since it was first added to the company website, would somebody please explain where my thinking has gone astray?

I must of course explain the reasons for my affection. I am not much of a sailor. That is not to say I do not find sailboats aesthetically pleasing or that I do not respect the obvious accomplishment that is crossing an ocean by sail. I just do not have the experience at sail and must admit a rather worldly affection for more room in a boat, especially a boat that I must call home for very long periods of time. Hence, my eyes tend to wander to that great passagemaker.....the Nordhavn 62, which to my eyes is a most beautiful and proven creature.

But a new Nordhavn 62 is well over 2 million dollars and of course it is POSSIBLE that both the main and wing give up the ghost a thousand miles from shore.....

You should also know that I do not intend to have more than one or two people on the boat for extended periods of time. Most of my friends would prefer to show up at the destination and save themselves the "pain" of a long voyage. And I am fine with that, as I am a bit of a loner and prefer extended periods with my girlfriend and maybe one other person per journey leg to help divide out the watch schedule, etc... But a more essential point is here: the boat must be capable of solo operation, if only for a short leg.

I must confess a growing fondness for comfort. Not the water condo
kind of comfort that we all see at the docks. If this was my thing I would not plan such ventures as a circumnavigation in a relatively small boat, which by its very nature demands at least some kind of sacrifice in the worldly comforts. But I do like the look of the full width Nordhavn pilothouse, and the trawler style, covered aft cockpit, which to me seems to be more safe and comfortable for a very long journey than a traditional raised cockpit one finds in the more sail oriented motorsailers. I realize these comforts demand the relatively truncated sailor's helm station located midship, but I think on a long journey the hours one actually wants to spend piloting the vessel out of doors is rather small. Cold air, rain, sea spray, and the like would tend to drive my non-adolescent soul to the comforts of a well appointed pilot house, where my girl can safely bring me coffee. My hours at the sail station would be limited to the relatively few days of perfect weather and perhaps a bit of sunbathing (drinking) while at anchor.

Before you think me weak, let us turn to more manly things like range, displacement, lazarette, watermaker, etc....It is obvious the 56 MS is not much of a performance sailboat, but I suspect the sails combined with a lightly throttled variable pitch propeller would dramatically extend the advertised 3000nm motoring range, which is not too bad itself considering the 750 gallon tank. This yields a similar motoring range as the lovely N62 with less than 1/3 the fuel. Of course a better comparison would be the N47, which has a similar displacement as the 56 MS, but accomplishes the 3000nm range at a slightly slower speed with twice the fuel. More important, if I had to punch through some salty seas I perceive the 56MS to be considerably less tipsy than the boxlike N47. I believe someone on this board questioned the 56MS' ability in open oceans. I would greatly appreciate any input on this subject as I consider her to be rather salty.

In summary, my eyes have begun to covet this vessel. I would greatly prefer to admit bad judgement while surfing the internet rather than surfing a long wave in the south Pacific. So please critique this vessel with discerning eyes and channel my enthusiasms elsewhere if you believe a more suitable vessel exists.

http://www.nordhavn.com/56/overview.php

[Guillermo]

Hi tsr, welcome to these forums!

I hade worked on some numbers for the Nordhavn 56 some time ago, although the lack of enough data makes the thing not trustable enough. Anyhow here you have it:

INPUT
Lh = 17,4 m
Lwl = 16 m
Bmax = 5,05 m
Bwl = 4,55 m (guess)
Draught = 1,83 m
HD = 0,9 m
Disp = 31910 kg
Ballast = 7658,4 kg (guess)
Sail area = 120 m2 (guess)
Power = 250 HP


OUTPUT
Beam/Length Ratio B/L = 3,31
Ballast/Disp Ratio W/Disp = 0,24
Displacement/Length Ratio D/L = 217,29
Sail Area/Disp. Ratio SA/D = 12,12
Power/ Disp. Ratio HP/D = 3,55 HP/ton
Hull speed HSPD = 9,71 Kn
Potential Maximum Speed PMS = 9,08 Kn
Velocity Ratio VR = 0,94
Comfort Safety Factor CSF = 1,61
Motion Comfort Ratio MCR = 47,6
Angle of Vanishing Stability AVS = 114,61 º
Roll Period T = 4,69 Sec
Roll Acceleration Acc = 0,07 G's
Stability Index SI = 0,93

If you provide me with more accurate data I'll work out a full new set of numbers for you.



Here similar (but more complete) data for the ATOA 64:

INPUT
Loa = 22,30 m
Lh = 19,50 m
Lwl = 17,32 m
Bmax = 5,40 m
Bwl = 4,86 m
Draught T = 1,60 m
Body draught Tc = 0,95 m
Disp = 36000 kg
Ballast = 10000 kg
Sail area = 146,4 m2
Power = 140 KW
Heeling Arm = 8,97 m

Angle of vanishing stability 132 deg
Downflooding angle 115 deg
GZ at downflooding angle 0,24 m
GZ at 90 degrees 0,61 m
Area to flooding (Agz) 55,48 m.deg
Area to AVS 58,67 m.deg

OUTPUT
Length/Beam Ratio L/B = 3,33
Lwl/Bwl Ratio Lwl/Bwl = 3,56
Ballast/Disp Ratio W/Disp = 0,28
Displacement/Length Ratio D/L = 193,26
Sail Area/Disp. Ratio SA/D = 13,64
Wetted Surface = 79,08 m2
Sail Area/Wetted surface SA/WS = 1,85
SA (metric)/ Power (Imp.) SA/HP = 0,77
Power/ Disp. Ratio HP/D = 2,40 HP/ton
Hull speed HSPD = 10,10 Kn
Potential Maximum Speed PMS = 9,8 Kn
Velocity Ratio VR = 0,97
Best cruising speed (1.1) CSPD = 8,29 Kn
Capsize Safety Factor CSF = 1,65
Motion Comfort Ratio MCR = 44,87
Moment of Inertia I = 9893467,65 Lb/ft2
Roll Period T = 5,21 Sec
Roll Acceleration Acc = 0,06 G's
Stability Index SI = 0,97


Base Length Factor (LBS) = 18,047
Displacement Length Factor (FDL) = 1,067
Beam Displacement Factor (FBD) = 1,061
Knockdown Recovery Factor (FKR) = 1,500
Inversion Recovery Factor (FIR) = 1,288
Dynamic Stability Factor (FDS) = 0,795
Vaw Not aplicable
Wind Moment Factor (FWM) = 1,000
Downflooding Factor (FDF) = 1,250
Delta = 5

STIX = 75,140


Cheers.

[brian eiland]

Originally Posted by tsr

I stumbled onto this website a while back and have spent many an hour searching the archives for pearls of wisdom. As this is my first post, I thank you in advance for whatever responses are to follow.

So please critique this vessel with discerning eyes and channel my enthusiasms elsewhere if you believe a more suitable vessel exists.

Welcome to the forum. I assume you mean you have searched this forum's archives??

If so I'm sure you may recoqnize my advocity for the multihull vessel form for long offshore passages, be it power or sail or motorsail. I might make the suggestion that you look thru the PowerCat forum and its archives for some knowledge of trawler cats and motorsail cats.

For instance here is a copy of a recent post by a gentleman Dennis Raedeke who has owned both sailing and power cats, his latest being a 57 power cat Wild Wind IV that he brought back across the Pacific on its own bottom, then up thru the Caribbean, to the Great Lakes;
"I have long been an advocate of sail assisted powercats. Wild Wind IV came real close to being one. Brian, If you put a rig on a powercat you are not
worried about tacking. Just start one engine and power tack. If one is not going to cross oceans then I wonder why you would want a rig on a powercat.

When I brought WWIV back from NZ I would have been more comfortable in WWIII, a 50' Prout sailing cat. Particularly from Hawaii to Seattle. I might have made the trip faster in WWIII. Just after leaving Hawaii I met with winds
ahead of the beam and I reduced speed to conserve fuel. In WWIII I would have been able to sail faster. When the wind went on the beam I would have sailed as fast or faster than I motored. Sail less cats are not the kindest in a beam sea. We rode in a beam sea all the way to 40 north before we turned east. I remember sailing from Jamaica to Panama in a fresh beam sea. The trip was fast and more pleasant that our trip out of Hawaii.

With all this said, I would only recommend a sail assisted cat if one was to do a lot of long distant off shore traveling. As you may be able to tell I have given the concept a lot of thought. Here are some of my ideas.

First of all the boat should be a good powercat in it's own right.

The rig should be removable and stowed onboard if possible.

The rig should be made most for reaching and running. When we circumnavigated I can hardly remember going to weather.

The rig should be able to carry very large down wind sails.

All sails should be roller furling or roller reefing.

Controllable pitch props would be essential. CPP's are fantastic for motor
sailing and the ability to feather the props is a must. Running one engine
saves a lot of fuel and engine hours.

The safety fact of a rig is important. Not to mention fuel burn.

When working on WWIV I did not pursue my sail assisted powercat design because I was not planning more long offshore trips other than bringing the boat home.

I have a design that I would glad to share with anyone who is interested.
Particularly someone who is planning a circumnavigation.
Part of the plan is a dual taper mast that has no shrouds and the mast could
be stored on board. Also no boom."

This was under a subject heading we were discussing, "Sailability of powercat hulls" in the Power-Catamaran Mailing List.

I might suggest you look thru the PowerCat archives and you might 'google' Wild Wind IV

[brian eiland]

Originally Posted by Dennis

I have long been an advocate of sail assisted powercats. Wild Wind IV came

real close to being one. Brian, If you put a rig on a powercat you are not
worried about tacking. Just start one engine and power tack. If one is not
going to cross oceans then I wonder why you would want a rig on a powercat.

Brian replied:
Hello Dennis & a Merry Christmas.

I agree with you that with the cost of rigs these days one definitely must
question a sailing rig on a cat, unless considering long range cruising or
crossing oceans. One exception though, if someone really enjoys sailing at
times, which I do.



_______________________________________________________

Originally Posted by Dennis

Sail less cats are not the kindest in a beam sea. We rode in a beam sea all
the way to 40 north before we turned east. I remember sailing from
Jamaica to Panama in a fresh beam sea. The trip was fast and more pleasant that our trip out of Hawaii.

Brian replied:
That rig has a way of moderating the motion, doesn't it



___________________________________________________

Originally Posted by Dennis

With all this said, I would only recommend a sail assisted cat if one was to
do a lot of long distant off shore traveling. As you may be able to tell I
have given the concept a lot of thought.

Here are some of my ideas.
First of all the boat should be a good powercat in it's own right.

The rig should be removable and stowed onboard if possible.

The rig should be made most for reaching and running. When we circumnavigated
I can hardly remember going to weather.

The rig should be able to carry very large down wind sails.

All sails should be roller furling or roller reefing.

The safety fact of a rig is important. Not to mention fuel burn.

Brian replied:
What would you think of this 'downwind sail-assisted vessel'?? Seems to meet
a lot of your requirements

New Age Trawler/Motorsailer
http://tinyurl.com/yo96xt

Instead of the tri configuration, just make it a cat

[FAST FRED]

it is POSSIBLE that both the main and wing give up the ghost a thousand miles from shore.....

With modern diesels almost all stoppages are fuel related , so loose one , and you will probably loose both.

The "cure" is well designed fuel tanks , proven designes have been available for 60 years or more.

FF

[Tad]

I'll take a stab at actually answering the question.

What do I think of the N56 Motorsailer? I think it’s a weird solution to non-existent problems. Don't you think that the sails, rig, and associated hardware and systems add huge cost? Will they not add a huge maintenance bill not to mention headache? I think that for the cost of all this gear and the associated cost of hauling it around the ocean one could have four main engines for quadruple redundancy!

The sailing rig will not add anything to your range unless you are willing to steer sailing vessel courses and slow down. Ocean sailing routes generally see fairly light winds, as you power into a breeze the apparent wind angle moves forward, forcing you to steer further off course. Angling around the ocean looking for a fair breeze burns more fuel than it saves. Bob Beebe figured this out 30 years ago. Power boats are efficient ocean crossers because they can go in a straight line or avoid contrary wind and current.

Aside from that this is an ugly boat (personal opinion) and the arrangement makes no sense. Tanks and machinery are seemingly scattered willy-nilly throughout the ship. The galley and dining area have no view and are miles from either helm, though perhaps there is a pass-through to the forward cockpit. The full width deckhouse is meant for dockside living not for going to sea.

The outside helm is where you need to be when navigating in restricted passages, or are trying to spot range lights at night, or are in a spectacular cruising area. I want my outside helm to be up high and well protected up to about chin height. This one seems really exposed and thus less useful in many conditions.

Tad

[Willallison]

So you liked it then Tad...!

Ditto to all that you say BTW. I see it as an early attempt to fill a foreseen niche in the market - with fuel costs on the rise, some people will start to look for more economical &/or environmentally sensitive boats. Whether their perception of what fills these requirements is well-founded is another question. In this instance, I think not.
Some bloke designed a boat call Passagemaker Lite that I think would do a better job...

[Tad]

From a global viewpoint the most efficient answer is to continue using the boat you already have, and not cause another boat to be built. Second most efficient answer is to buy an existing boat, again not causing any additional manufacturing, use of raw materials, shipping, cutting of trees, drilling of oil, digging of metals, etc.

Third most efficient answer comes from George Buehler, stick a pole through the foredeck and hang a Chinese lug sail off it. No shrouds, chain plates, sheet winches, hydraulics, computers, or furling gear. This rig can be built from found materials. Simple and effective, it will work when all else fails. The cost is very low and no huge corporation profits very much. The sail can be made from a $35 plastic tarp (yes, some corporation made it from oil).

Least efficient in overall terms is to build a new, so called "efficient" boat. But if we are going to do this why must we haul 17,500 pounds of ballast every place we go? Why can't all the machinery be in one part of the boat, say right aft where we don't have to live around it? Maybe behind a fire proof bulkhead? And why can't the tanks be concentrated amidships? And why can't we have a simple, low stress, partially stayed rig that does not require hydraulics to handle? And a well designed sailing cockpit with good protection will be nice too.

Something like this....

[Guillermo]

Interesting post, Tad.
First: not to buy. Second, if you buy, buy used.
Or then, go chinese....

As a matter of fact we should apply this philosophy to cars. I usually buy used ones. This my last was bought from new 400.000 km ago (by the oil company I worked for) and now I'm going to re-engine it instead of buying a new one. Much cheaper, much more efficient.

I like your design. Is it a kind of semidisplacement monohull motorsailer?

Cheers.

[Tad]

Guillermo,

I do practice this philosophy as best I can. My current vehicle is a 17 year old van, bought well used several years ago, I imagine it will last me another 10 years. The outboard I use every day is over 30 years old, and we have the oars for lowest carbon emissions.

The powerboat with sails is a displacement hull, with a top speed of just over 10 knots. This is a full keel version with single engine in the keel as part of the ballast.

[Guillermo]

You win! My car is only 13 and I hope it to last at least another 300.000 km after re-engining. But my boat is 37 and still running strong, so I think this compensates.

Your design is a very interesting one. I like the streamlined 'box' keel, L/B ratio, feathering propeller, main section profile and shape of waterlines and longitudinals. What are her Ballast and Cp? What is the reason for the twin rudders configuration?

Working out some numbers for her (I asumed asumed ballast as 17770 lbs, body draught as 2.30 ft, Cp = 0.64, Cwp = 0.7 and Cm = 0.72) I think that, although with a good reserve of stability, she seems to be somewhat tender as per the GZ curve calculator I use to estimate things. As this calculator is still under evaluation and I'm trying to check it against the real things, I'll heartly appreciate if you could provide to me your calculated GZ curve whenever possible, for comparative purposes.

By the way, I have a client who loves your designs (as I do). Perhaps we could collaborate in the future.....

All the best from this rainy but joyful 'Día de Reyes' in Galicia.

[brian eiland]

Originally Posted by Tad

Guillermo,
I do practice this philosophy as best I can. My current vehicle is a 17 year old van, bought well used several years ago, I imagine it will last me another 10 years. The outboard I use every day is over 30 years old, and we have the oars for lowest carbon emissions.

Originally Posted by Guillermo

You win! My car is only 13 and I hope it to last at least another 300.000 km after re-engining. But my boat is 37 and still running strong, so I think this compensates.

I think I have you both beat in the auto department. I still drive a 35 year old Mercedes (1973) that I've owned since it was 4 years old.

Now, it has a little more rust than in these photos, but it runs great. In fact this car has been so good to me I recently bought another of the exact same year with very little rust, so I could combine the two for another 10 plus year's service. But alas I am moving to Thailand and must sell both, preferable as a pair.

I think I inherited this 'no need for a new car' thing from my father. Plus I aways did like the looks and practicality of this MB model. I've often wondered how mankind could justify rapeing the earth for the huge amount of raw materials it takes to build new model cars every year, and fill up the landfills with discarded models.

And finally, I've always liked your designs Tad.

[Tad]

Guillermo & Brian,

Thanks for your comments, this thread is really drifting which is natural I guess.

Nice car Brian, I looked hard for a Mercedes diesel to replace my old Saab a couple of years ago. As it turned out the van is very practical but it does burn twice the fuel.

The concept above will certainly be somewhat tender compared to the usual deep keel, heavily ballasted and beamy sailing cruiser. For instance the Beneteau 57 is 2.33' wider with 2.25' deeper draft. She carries 500 sq.ft. more sail area and 15,200 pounds of ballast. Displacement is very similar at about 48,000 pounds. Her triple spreader sloop rig with hydraulic furlers will be far heavier than my short hollow wooden spars with rope shrouds. The Beni's heeling arm will be greater.

The concept boat's ballast will be made up of 8000 pounds of lead, plus about 3000 pounds of engine and gear in the form of a Gardner LXB 150, plus another 1000 pounds of batteries and possibly an auxiliary generator. All this will be in the keel as low as possible. I'm guessing at a Dellenbaugh Heel angle of about 14.88 degrees, which is a bit tender but not unknown.

My theory on this vessel's operation is that the sail area is needed to be able to make headway under sail alone in lighter air. As the wind increases you just drop one or more sails, and this will happen in a 12-15knot wind under normal circumstances.

The twin rudders are a thought on gaining rudder area at a given (shallow) depth.

Tad

[Guillermo]

Originally Posted by Tad

The twin rudders are a thought on gaining rudder area at a given (shallow) depth.

Just as a first thinking, I'm wondering if rudders being so close will not negatively interfere one with the other when sailing...

[yipster]

intersting thread, do belive there is space for motorsailers tho
Guilermo might be right it better has at least a chordlenght in between but i like that dual rudder setup
reminds me i forgot what side a single rudder goes of the shaft by what prop rotatation
seeking comments on a more radical motor to sail transition in my gallery