Fleming 58 video

[Portofino]

Would this suggestion be viable? I wonder if running large engines at idle more or less, continuously for days, would be damaging for the engines?

It’s to do with “ load “ or low load - more / less same as idle , rpm in gear .Thats why I,am NOT suggesting above — 1 st click for us P people to run @ D speed ,
Read here .
https://daim.idi.ntnu.no/masteroppgaver/011/11083/masteroppgave.pdf

 

[Bouba]

Actually the 64 is the one I would have if my wallet could stretch that far. I was really impressed with the 64 at SIBS last year although I still have to get my head around the idea of a single engine on such a monster of a boat!

You do know that when your Nordhavn is finished you are expected to fly out to China then drive it home

 

[Zing]

It’s to do with “ load “ or low load - more / less same as idle , rpm in gear .Thats why I,am NOT suggesting above — 1 st click for us P people to run @ D speed ,
Read here .
https://daim.idi.ntnu.no/masteroppgaver/011/11083/masteroppgave.pdf

Thanks for the link. Uh oh, that's a 137 page response. One to keep for my next long haul flight.

 

[MapisM]

Out of interest, P, why do you say that? As far as I understand, the 63 was not so much a replacement for the 62 as an alternative to the 55/60 for customers who were looking for a similar aft pilot house arrangement to the 62. Certainly, Nordhavn make no secret of the fact that it is based on the 55/60 hull. I suspect that if Nordhavn tried to make a real replacement for the 62, which I agree was a great boat, the cost would be prohibitive and put it into the same territory as the 64

Back to your question, here's my old story - straight from the horse's mouth.

I was driving from San Diego to L.A., during the worst post-financial meltdown times, when each and every boatyard was more busy dealing with cancelled orders than anything else.
And I knew of a N62 which was for sale, advertised as moored in Dana Point - which is right along the road, for those unfamiliar with that stretch of the US W coast.
Btw, I had already seen another one some years earlier, and I fell in love there and then.
But her price was way above my own limits of a "still crazy, but you only live once" sort of amount.
This other one was also advertised with an asking price that I neither could nor would have paid for a boat - ANY boat (around 1.4M$, IIRC).
Otoh, the USD was by then very weak, and there were stories of boats sold in the US at just a small fraction of their asking price.
So I thought, what the heck, let's have a look.

When myself and S entered the rather nice Nordhavn offices within the marina, we only found a lady who knew nothing about the boat we were interested to see, and asked us to wait for a second because there was someone else who could have possibly known better.
A minute later, she introduced us to Jeff Leishman, no less, who was behind a desk covered with all sort of paper drawings.
He explained us that the N62 ad which I found on the web was very old, and the boat was already sold and moved elsewhere (to PNW area, IIRC).
BUT, he proudly told us that they could have offered a great deal on a brand new model which was meant to replace the 62 - i.e. the 63.
He showed us some large drawings, explaining the pros of a narrower/simpler/lighter construction which would have allowed them - together with the more efficient production of their Chinese factory - to build us a new boat for 1.8M$, i.e. not much more compared to the prices that some 10 years old N62 were fetching on the market.
Long story short, we discussed for maybe one hour or so, during which I couldn't see one single thing which I would have called an improvement over the 62, no matter how hard Jeff tried.
Btw, among other stuff, I remember one thing he particularly struggled to argue with, i.e. my objection that I'd rather have a boat built in a very well proven yard like Ta Shing, rather than in a newly established plant in China, whose only advantage is a lower cost of (unexperienced) manpower.
In hindsight, I guess he was already aware of the many issues with their Chinese built boats, which became widely known to everybody not much later...

Anyway, back to your point, I know nothing of how Nordhavn positioned the 63 later, and if you tell me that they don't even try anymore to suggest that she's the 62 replacement, I take your word for it.
I suppose that since the differences are so obvious - particularly to their typical clients, which are way above average in terms of technical competence - it didn't take long before they realized that it takes more than a larger model name to sell a smaller and somewhat worse boat!
But I can assure you that what Piers said - i.e. that they introduced the 63 as a 62 replacement, at least initially - is spot on.

 

[MapisM]

I expect the issue Piers mentioned, that his stabilisation is not as good as he would like is down to the Fleming having smaller fins than he needs. The Fleming being capable of 20+ kts should have the fins sized for a higher speed than the 8kt he normally cruises at, just as P boats will have even smaller fins as they will be designed for the yet higher cruising speeds. It's another one of those boat design compromise problems.

Pardon? That's a non sequitur, if I've ever seen one.
What Piers said is... the stabs are excellent on our Play d'eau but we have nothing to cope with 'at anchor'
In other words, his fin stabs are NOT a zero speed version (exactly as the Naiad in my old lady weren't).
That doesn't make them less good while cruising, though.
Fins are so effective in stabilizing any monohull vessel while underway, at any cruising speed, that the fin size is almost irrelevant. Well, within reason, of course.

 

[Zing]

Pardon? That's a non sequitur, if I've ever seen one.
What Piers said is... the stabs are excellent on our Play d'eau but we have nothing to cope with 'at anchor'
In other words, his fin stabs are NOT a zero speed version (exactly as the Naiad in my old lady weren't).
That doesn't make them less good while cruising, though.
Fins are so effective in stabilizing any monohull vessel while underway, at any cruising speed, that the fin size is almost irrelevant. Well, within reason, of course.

I suggested that the reason why he couldn't get adequate stabilisation was because the fins were too small. They were small I suggested because they may have been designed to work at planing speeds. Surely the fin size goes up, the slower you cruise? Surely the bigger the fin, the better it will work when stationary?

 

[MapisM]

Yup, AOTBE that is true, but the point is different.
Zero speed fin stabs are different from ordinary cruising stabs in many other ways.
That's the reason why upgrading from non-zero speed to zero-speed in practive means replacing the whole system.
In Piers boat, the reason why he can't get stabilization at anchor is that he doesn't have a zero speed equipment, not that he has small fins (hence jfm previous suggestion).

 

[Portofino]

Drag s a big factor in speed of a planing boat .
Not many fast planers fit fins .
Saw a Riva ego 68 having then fitted in the yard a few years back ( curved fins btw ) .
I asked the owner why ? He said ( boat 1 y old ) that this was his second boat in as many years as the wife refused to come out on the first due to sea sickness reasons .
Fitting fins was his last throw of the dice before packing up .
Later on , I met him again and he told me it worked , saved his marriage but he had lost 5 knots .

On this below pic - extreme measures to reduce drag of dangling things , fit the rudders to a hydraulic bar to lift then up ,go faster .
View attachment 67073

So fitting fins to this , not very sensible!

 

[EricJ]

Interesting debate on P vd SD vs D.
Where do the Dutch steel D boats like Linssen, Boarnstream, Steeler etc fit in this? These are generally well-built boats, not with the ocean crossing ability of a Nordhavn, but more made for cruising than sunlounging.
I quite liked the Linssen Range Cruiser which was discontinued a few years ago after a fairly short production run. More modern looks than the other Linssens, spacious for its size which was about 45 ft I think (ok, smaller than what was discussed on here). Also Boarnstream is expanding their Elegance line with larger boats up to 18m and flybridges.
These look like interesting boats for those who don't want to do ocean crossings with a D boat and thus don't need all that height and weight of a Nordhavn.

And what about an aluminium boat like a Van der Valk Continental? They seem to go with IPS quite often, but leaving that part aside, what is the panel's opinion about an aluminium SD boat for the type of cruising that was discussed (longer trips, Med but also incl northern Europe)?

 

[Portofino]

Interesting debate on P vd SD vs D.
Where do the Dutch steel D boats like Linssen, Boarnstream, Steeler etc fit in this? These are generally well-built boats, not with the ocean crossing ability of a Nordhavn, but more made for cruising than sunlounging.
I quite liked the Linssen Range Cruiser which was discontinued a few years ago after a fairly short production run. More modern looks than the other Linssens, spacious for its size which was about 45 ft I think (ok, smaller than what was discussed on here). Also Boarnstream is expanding their Elegance line with larger boats up to 18m and flybridges.
These look like interesting boats for those who don't want to do ocean crossings with a D boat and thus don't need all that height and weight of a Nordhavn.

And what about an aluminium boat like a Van der Valk Continental? They seem to go with IPS quite often, but leaving that part aside, what is the panel's opinion about an aluminium SD boat for the type of cruising that was discussed (longer trips, Med but also incl northern Europe)?

Metal hull + a rope fender warped arround is ok for locks , and occasional ice breaker duty .
Plastic would be my go to material for a boat. .Ease of maintenance and easier for the builder to form into better looking shapes .
There was Linseen grand sturdy 40 something , in our Marina once for a couple of years Cote d Azur .
It was green too .Steel .
Anyhow it was at the end of our jetty so got to eye ball it lot .
Rust spots from dings in the paint and welds .The rope fender is too high for normal concrete Med Marins furniture like fuel pontoon .
If you gonna do inland rivers / canals fine , so that it does not get cracked banging about loose in torrent in the locks .
10 or more times / day .You are bound to cock up at least 1 of those transits and thank the man upstairs it’s steel

Aluminium, again corrosion worries for the ave bod .,components connected causing it to fizz .To much hassle trying to slow down electrolysis.
Folks like Abramavich don,t give a toss as a £2 M refit in the dry dock every now and again is do able and part of Al boat ownership I guess .

A plastic boat for Med and occasionally coastal inland .
AMHO

 

[Deleted User YDKXO]

Anyway, back to your point, I know nothing of how Nordhavn positioned the 63 later, and if you tell me that they don't even try anymore to suggest that she's the 62 replacement, I take your word for it.
I suppose that since the differences are so obvious - particularly to their typical clients, which are way above average in terms of technical competence - it didn't take long before they realized that it takes more than a larger model name to sell a smaller and somewhat worse boat!
But I can assure you that what Piers said - i.e. that they introduced the 63 as a 62 replacement, at least initially - is spot on.

Good story P. I can only relate what I've been told at exhibitions and a Nordhavn event in the UK. I was told that the 63 was another version of the 55/60 hull for customers who wanted an aft pilot house version like the 62. If you look on their website http://www.nordhavn.com/models/63/ they make no bones about this fact and dont attempt to suggest that it is a replacement for the 62

With regard to the change to the Chinese factory, yes I also understand that there were some initial quality issues but changing the location of any manufacturing process is almost bound to lead to all sorts of unseen problems which manifest themselves in product quality issues. The important bit is how the company deals with those quality issues and how it addresses the problems that caused them in the long term. I regularly dip into the Nordhavn Dreamers forum which has partially morphed into a Nordhavn owners website and I dont see many if any adverse comments about quality issues, just owners who generally happy with their boats. Yes I do realise that there is another closed Nordhavn Owners forum but you would expect unhappy owners to use an open website to publicise their complaints. Another thing that has impressed me about Nordhavn is that when I go to an exhibition, I tend to always see one of the owners of the company there who is only too happy to talk about his product. In other words they are ready and willing to stand behind their product. Literally!

 

[Piers]

I suggested that the reason why he couldn't get adequate stabilisation was because the fins were too small. They were small I suggested because they may have been designed to work at planing speeds. Surely the fin size goes up, the slower you cruise? Surely the bigger the fin, the better it will work when stationary?

As speed decreases, the angular movement of the fins increases to compensate. Works well but there's a time with a heavy sea/slow speed combination that the fins can't cope as well. Whether larger fins would be the answer I can't say.

 

[NBs]

Metal hull + a rope fender warped arround is ok for locks , and occasional ice breaker duty .
Plastic would be my go to material for a boat. .Ease of maintenance and easier for the builder to form into better looking shapes .
There was Linseen grand sturdy 40 something , in our Marina once for a couple of years Cote d Azur .
It was green too .Steel .
Anyhow it was at the end of our jetty so got to eye ball it lot .
Rust spots from dings in the paint and welds .The rope fender is too high for normal concrete Med Marins furniture like fuel pontoon .
If you gonna do inland rivers / canals fine , so that it does not get cracked banging about loose in torrent in the locks .
10 or more times / day .You are bound to cock up at least 1 of those transits and thank the man upstairs it’s steel

Aluminium, again corrosion worries for the ave bod .,components connected causing it to fizz .To much hassle trying to slow down electrolysis.
Folks like Abramavich don,t give a toss as a £2 M refit in the dry dock every now and again is do able and part of Al boat ownership I guess .

A plastic boat for Med and occasionally coastal inland .
AMHO

 

[jfm]

As speed decreases, the angular movement of the fins increases to compensate. Works well but there's a time with a heavy sea/slow speed combination that the fins can't cope as well. Whether larger fins would be the answer I can't say.

Yup. But doubling the speed and keeping the same fins and fin angle increases the torsional anti roll force by 4x, whereas doubling the fin size and keeping fin angle and speed constant increases the torsional antiroll force by only 2x.

That's why I say above the most seaworthy boat in a big beam sea, or aft of beam sea, is a P boat with fins (not gyros; they're useless in a big sea). With a P boat, you just speed up if you need more stabilisation, which you can't do in a D boat. Obviously in a big head sea, a Nordhavn/Fleming/etc is top of the class and a P boat has its limitations. I'm talking big seas here where the deepV of a P boat isn't going to help you going upwind.

Below vid is a F7-8 blowing for 3 days with 100miles of fetch. The boat is heading due south, 8 miles south of Cannes/Antibes/Monaco in open sea, with a strong mistral blowing from the west. As ever the sea was bigger in real life than the video suggests. See for example the wind/waves at 0:06s and 0:32s. This is a P boat with fins, at 20 knots, and you can see that the transom remains parallel to horizon throughout. There is no roll at all. There comes a size of wave (about this size) where a 10 knot D boat can't do this and starts to roll, whereas a good P boat with fins will never roll because it can simply increase speed. Increasing speed by 40% will increase antiroll torque 2x, because it is a square law.

https://www.youtube.com/watch?v=01Nij1Ulyhg

 

[Piers]

Yup. But doubling the speed and keeping the same fins and fin angle increases the torsional anti roll force by 4x, whereas doubling the fin size and keeping fin angle and speed constant increases the torsional antiroll force by only 2x.

That's why I say above the most seaworthy boat in a big beam sea, or aft of beam sea, is a P boat with fins (not gyros; they're useless in a big sea). With a P boat, you just speed up if you need more stabilisation, which you can't do in a D boat. Obviously in a big head sea, a Nordhavn/Fleming/etc is top of the class and a P boat has its limitations. I'm talking big seas here where the deepV of a P boat isn't going to help you going upwind.

Below vid is a F7-8 blowing for 3 days with 100miles of fetch. The boat is heading due south, 8 miles south of Cannes/Antibes/Monaco in open sea, with a strong mistral blowing from the west. As ever the sea was bigger in real life than the video suggests. See for example the wind/waves at 0:06s and 0:32s. This is a P boat with fins, at 20 knots, and you can see that the transom remains parallel to horizon throughout. There is no roll at all. There comes a size of wave (about this size) where a 10 knot D boat can't do this and starts to roll, whereas a good P boat with fins will never roll because it can simply increase speed. Increasing speed by 40% will increase antiroll torque 2x, because it is a square law.

https://www.youtube.com/watch?v=01Nij1Ulyhg

Really interesting. So in seas when Play d'eau starts to roll as the fins can't hold her level, the answer is larger fins. Yes?

 

[NBs]

When I did the 3 day technical course on the Cummins engines in Play d'eau, I was told that running at low rpm was not an issue since the oil thermostats would keep the oil at working temperature. Hence, no bore glazing.

Hi

I agree with you, you can run a diesel engine at low revs long period of time if it reaches temperatures in which it recommended, and it is not a danger to the machine. Especially modern engines like common rail like Cummins QSB. I have found this gain US Cummins guru Tony Athens who worked in practical work to repair engines for over 30 years.

Tonys arthicel load vs engine life time

https://www.sbmar.com/articles/engine-life-vs-engine-loading/

NBs

 

[Portofino]

Hi

I agree with you, you can run a diesel engine at low revs long period of time if it reaches temperatures in which it recommended, and it is not a danger to the machine. Especially modern engines like common rail like Cummins QSB. I have found this gain US Cummins guru Tony Athens who worked in practical work to repair engines for over 30 years.

Tonys arthicel load vs engine life time

https://www.sbmar.com/articles/engine-life-vs-engine-loading/

NBs

I think most modern Diesels have spray jets under the pistons along with oil journals in the crank .
I fact the oil is used to cool too ,via a cooler anything to shift heat - nothing new there or unique.
Indeed most high performance petrols ( high rpm ) sports stuff like Porches and esp Ferrari extensively use the oil to cool as well as the traditional lubrication .

Do you have oil temp gauges ?
I have and it drops at low rpm .I Also crucially have EGT,s and that drops too .
I try to keep the EGT north of 500 degrees and oil temp in the 90-100 zone .

Without oil temp gauges and EGT —- how do you know low rpm extended runs are NOT harming ?

Tony Athens article is about overload, - a good read btw and relevant for those running about with dirty props + added kg,s ,or basically wrong ( too much pitch ) prop for the boat testers when new re speed think new FL Targa 63 GTO - just nudging over 30knots — 31. something @ Cannes .

How ever long periods @ LOW rpm brings a different set of problems
Apologies for the size ,but study this study carefully .

Diesels runing underloaded for long periods have shorter lifespans.

Here it is again from my post # 141 ^^^

https://daim.idi.ntnu.no/masteroppgaver/011/11083/masteroppgave.pdf

 

[jfm]

Really interesting. So in seas when Play d'eau starts to roll as the fins can't hold her level, the answer is larger fins. Yes?

Yes, if you can't speed up and if there are no other limitations in play.

It could be that your hydraulics let go at a point when you have not deployed full fin angle (full to the point of almost stall, I mean, but you know more about flying than me!) and in that case what you want is more fin angle. But of course you couldn't have it by just dialling up the pressure relief valve setting, because you might break something. So you would need whole new stabilisers. And if what you need is bigger fins, then again you need whole new stabilisers.

On hydraulic pressures, I think you have Trac actuators with single cylinder, double acting. That means the actuator can apply more torque in one rotational direction than the other, due to the "lost" force caused by the cross section of the hydraulic ram. Worse still, Trac don't hand their actuators, so you basically have more hydraulic force to stop the boat rolling to the left than you have to stop it rolling to the right (or vv). The way to overcome this is to hand the actuators at the design stage, or to have 2 cylinders on each ram, one pushing an one pulling, so to speak. To some extent I'm splitting hairs here because you'll rarely reach your stabiliser limits, but its isn't engineeringly beautiful to have this imbalance. On an awesome boat like yours I wouldn't hesitate to rip out the Trac stuff and fit a pair of new Sleipners, with zero speed stabilisation to boot (just as we just did on my brother's Aquastar 74)

 

[Deleted User YDKXO]

(not gyros; they're useless in a big sea)

We tested our boat in similar sea conditions off the Porquerolles this year. The gyro was at its most effective with the boat stationary just lying beam on to the sea which are conditions which would normally have any boat rolling like a pig. In fact my SWMBO was able to stand on the flybridge sunpad without bracing herself which was testament to the effect of the gyro. But what was noticeable was that as soon as we started to make way the effect of the gyro was reduced and she was not able to stand unsupported and as I said in another thread, by 10kts, the effect was negligible

This makes me wonder whether, instead of fins which as you say are very much more effective the faster you go, whether D or slow SD boats would actually be better stabilised with a large gyro rather than fins

 

[Deleted User YDKXO]

On hydraulic pressures, I think you have Trac actuators with single cylinder, double acting. That means the actuator can apply more torque in one rotational direction than the other, due to the "lost" force caused by the cross section of the hydraulic ram.

Agree, not a proper engineering solution but the other side of the coin is that the hyd cylinder will act faster in one direction than the other, albeit, as you say, with less force. Just wondering but how much does speed of fin actuation affects stabilisation?