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  #16  
Old 02-18-2017, 10:51 AM
BertKu BertKu is offline
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Quote:
Originally Posted by valery gaulin View Post
I am trying to figure out what type of ballast do these Lemsteraak have! Can't find any answer online. Is it because they don't have any and they only rely on hull from stability? It seams that they are very wide for their lenght.

Now if they don't have any ballast and they just rely on hull form stability having such a huge displacement it make sense to build out of steel. But would it not be better for stability if they would built the boat out of a lighter material than steel and use the weight save as ballast in the bottom of the boat? I am sure they have thought about that but maybe the pros vs the cons is negligeable this is the reason why they still make them out of steel.

I fell that I am missing something....


Second questions: How do they maintain their steel, they all seams to be so impecably maintain without any sign of rust. Do they paint every year their boat?
I don't think you have to be too worried about the ballast. I would be more worried about the control of the rudder. Some Hollanders have some pretty heavy muzzles. Nice, when you have sunny days, but what about some strong winds with rain. I would consider some mechanism for that part. In the production from the photo's it looks like they use red oxide paint. I assume some high quality finish paint is then used for the final product.
I doubt it that they paint the boat every year. You need to email some of the skippers and compliment them on their beautifully boat. Ask them how they maintain their metal boats or ask the boatbuilder what the cost is for the plans and maintenance. Bert
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  #17  
Old 02-19-2017, 11:55 AM
valery gaulin valery gaulin is offline
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Building material option for a Lemsteraak:

Wood with epoxy impregnation on the outside only and for below the waterline tar coated covered with cooper sheet (1mm- 2mm thick). No more maintenance, abrasion resistance, for beaching, anti fouling material, cooper being in the bottom would also help for lower center of gravity. Wood is also an excellent natural insulator and it floats.

Now what type of wood? Plywood exterior grade, Plywood pressure treated, Cedar stip??? Any other idea?
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  #18  
Old 02-19-2017, 03:01 PM
BertKu BertKu is offline
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Originally Posted by valery gaulin View Post
Building material option for a Lemsteraak:

Wood with epoxy impregnation on the outside only and for below the waterline tar coated covered with cooper sheet (1mm- 2mm thick). No more maintenance, abrasion resistance, for beaching, anti fouling material, cooper being in the bottom would also help for lower center of gravity. Wood is also an excellent natural insulator and it floats.

Now what type of wood? Plywood exterior grade, Plywood pressure treated, Cedar stip??? Any other idea?
Some time ago, the Dutch has developed a method to make pine wood, one of the cheapest and most available wood in the world, processed under pressure or in vacuum, can't remember what the article said, with vinegar and it was suitable for sea and rough environmental treatment. Also they stated, it was used for boat building and it last a lifetime. Maybe you can find out more about it. I personally would make it from French plywood. It has 0.45 SWG, i.e it floats nicely. I would get an heavier engine in the belly for lowering center of gravity. Or oak wood, good for the center of gravety. But Valery, you need a better advice from the builders of those type of boats, then from me. Get yourself a copy of "Spiegel der Zeilvaart" issue April 2016 for Euro 4.95 or the one from February 2017. Bert
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  #19  
Old 02-19-2017, 03:47 PM
CT249 CT249 is offline
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Originally Posted by Angélique View Post
-
The race video shows the in Aken-circles highly controversial 2010 Blom* built 15.5 m Lemsteraak VA 210 Warber, with her by Van Oossanen Naval Architects fully CFD redesigned hull and every piece fully CAD redesigned + optimised, and CAM built by Blom, including the stronger and stiffer and 50% lighter as before CAD/CAM built, internal and external 100% round, as well as the inner and outer diameter and the wall thickness tapered all the way up, woden mast. Warber was caught cheating the class rules for the hull form after building her, while the whole design was approved by the class organization before building. Then after some hull modifications she got a only once granted permanent dispensation for the rest of the non compliant hull issues, since the build was started before the new class rules for the hull form became effective, that's this Aak's story in kinda short. Dirk Blom, the builder, owner, and also the skipper of Warber in the race video, tells here about her features Video in Dutch in Feb. 2011 before the whole class rule controversy took place. Jan de Vries, owner and skipper in the race video of the 12.19 m X-40 Eala PDF, has here a note online in Dutch about the race. This Aak's NA Pieter Van Oossanen has here the magazine article about the race online PDF in Dutch, the text is copyable, so it can be put in an automatic translator. At the end of the race video Dirk Blom tells the Aak was beaten on less maneuverability around the buoys, and also on less acceleration performance. I would like to see them race on a really long course . .
* Note: I've just marked the Blom Shipyard section in post # 6 with a red - in the left margin, in order to find it back easy since they also appear in this post a few times.

P.S. - Blom Shipyard and Dirk Blom are related as family, but Dirk has his own Lemsteraken business, Blom Shipyard did built the hull of Warber.
Thanks for the links. The article makes clear on thing that had been puzzling me. Early on in the video the X is clearer higher and faster upwind, but the video shows the Aak not too far behind at the mark. The article says that there was a windshift after the start that allowed both boats to make the mark without tacking, which obviously meant that the X Yacht lost most of the advantage it had gained through superior pointing.

Given that one boat was 25% longer than the other and carries almost twice as much sail, it's not surprising that the bigger boat had similar top speed in conditions where both boats would have been pretty limited by hull speed. Given lighter winds, surfing conditions or a tighter course, the modern boat would be even further ahead.

None of this is to dispute that the Aak is a fine craft built for a very different purpose. I'd love to go and have a sail on one of them.
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  #20  
Old 02-19-2017, 09:27 PM
valery gaulin valery gaulin is offline
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Thank you Bertku for the info. Actually if I ever get to the point of actually really building a Lemsteraak I would get a plan from a professionnal designer that specialise in these kind of Yacht.

Right now, I talk and I dream about these boats because I am amazed at the features these boats have. They basically have all my wants!!!

Someone mention in a comment above that the tiller is probably heavy, I actually thought the same thing! My solution while thinkjnh about it was to actually balance the rudder. Basically I am more inclined at using a submersible type of electric propulsion that would be integrated in the rudder with the propeller at the end of the rudder. It would help alot for port maneuvrability to be able to steer with the propeller on the rudder. Anyway by having this setup there is no need for the rudder to be chop for the place of the shaft and propeller from an traditonal inboard arrangement. This way the rudder could be filling that empty spot all the way to the keel and it would make it a balanced rudder. It will for sure help to reduce the muscle needed to steer these type of boat without going for the wheel arrangement.
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  #21  
Old 02-19-2017, 09:43 PM
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Angélique Angélique is offline
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Quote:
Originally Posted by CT249 View Post

Thanks for the links. The article makes clear one thing that had been puzzling me. Early on in the video the X is clearer higher and faster upwind, but the video shows the Aak not too far behind at the mark. The article says that there was a windshift after the start that allowed both boats to make the mark without tacking, which obviously meant that the X Yacht lost most of the advantage it had gained through superior pointing.

Given that one boat was 25% longer than the other and carries almost twice as much sail, it's not surprising that the bigger boat had similar top speed in conditions where both boats would have been pretty limited by hull speed. Given lighter winds, surfing conditions or a tighter course, the modern boat would be even further ahead.

None of this is to dispute that the Aak is a fine craft built for a very different purpose. I'd love to go and have a sail on one of them.
The X won the first two races of a ‘‘best of three’’ so the third race wasn't sailed. The article tells about the two sailed races. From the article's text PDF and looking at the video I think the first part of the video shows the start of the first race and also the top mark rounding in the first race, and then at the end of the video the finish of second race, but I'm not sure as it nowhere tells which part of the video shows which part of the two sailed races, also the video and the article don't provide any intermediate times at the marks, and not even total elapsed times of each race, and also not the distances between the marks, respect for both teams though, the Aak became second, and the X second to last . .

From the article: - | - Jan de Vries (X-40) Eala - | - Dirk Blom (Aak - Lemsteraak) Warber - |

Quote:
‘‘ . . . . Om het helemaal echt te maken, besluiten we een ‘best of three’ te varen. . . . . ’’

Race one: ‘‘ Met één klap naar de bovenboei

Jan de Vries pakt het slim aan bij de eerste start. Onder de Warber en dan omhoog. Dirk Blom moet meeloeven, de snelheid zakt wat uit de aak en ofschoon beide boten vrijwel gelijktijdig over de startlijn gaan, is de X duidelijk in het voordeel: hij accelereert sneller en heeft daardoor al gauw een bootlengte voorsprong. Omdat de wind draait, is het eerste kruisrak geen kruisrak meer en kunnen beide jachten met maar één klap naar de bovenboei. Eala rondt als eerste, zet in een mum van tijd de spinnaker en is weg. Aan boord van de Warber duurt zo’n manoeuvre aanmerkelijk langer. Bovendien ligt de halfwinder aan de verkeerde kant. Omdat de baan niet zo heel lang is, heeft het geen zin om die om te leggen en daarna alsnog te zetten. Jammer, want juist die halfwinder had op deze koers voordeel gehad boven een spinnaker. Na de benedenboei volgt een tweede indewinds rak, opnieuw een downwind koers en gaan de jachten over de finish. De Eala met enkele minuten voorsprong op de Warber - een afgetekende overwinning. ’’


Race two: ‘‘ Echt geen kans

Nadat we de bovenboei wat naar het westen hebben verlegd, en de benedenboei wat naar het oosten is het tijd voor de tweede start. Dirk Blom laat zich dit keer niet in de luren leggen en de Warber komt op volle snelheid over de startlijn - gelijktijdig met de Eala. ’t Is nu wel een écht kruisrak en het valt op dat de aak inderdaad minstens zo hard loopt als de X en in hoogte maar een paar graden hoeft toe te geven. Tot de eerste klap gaat alles goed voor de Hylpers, maar na die eerste manoeuvre tekent zich opnieuw een afstand af. Het moge duidelijk zijn: manoeuvres met de X kunnen gewoon veel sneller worden uitgevoerd. En daarin zit hem hét verschil. Opnieuw is Eala ruim als eerste binnen. Dirk Blom neemt z’n verlies als een vent: “Bij elke manoeuvre verliezen we. Deels ook doordat we de boot nog niet optimaal kunnen varen. Bovendien moet je met dit wisselende weer constant spelen met het kluiverstag en de bakstagen. Dat is essentieel om het uitsterste uit de boot te halen en ook dat hebben we nog niet optimaal in onze vingers. Op een kort baantje als dit maken we geen kans tegen een vergelijkbaar scherp jacht. Op langere banen wel. Kijk maar naar de 24-uurs Race; die winnen aken regelmatig.” Jan de Vries kijkt niettemin tevreden terug op de hele onderneming: “Een overduidelijk verschil. Gelukkig wel zeg.” Toch met enige opluchting… ’’
Note: ‘‘Hylpers’’ in the quote is a Frisian word for the Dutch word ‘‘Hindeloopers’’ which is ‘‘people from Hindeloopen / Hindeloopers’’ in English, which is the Aak's team here.
‘‘Warber’’ is a Frisian word for: ‘‘ active - diligent - assiduous - industrious - efficacious - hardworking - zealous - bustling - eager - painstaking - busy ’’
. . . . as far as I understand Frisian & English . .
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  #22  
Old 02-20-2017, 04:27 AM
BertKu BertKu is offline
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Originally Posted by valery gaulin View Post
Thank you Bertku for the info. Actually if I ever get to the point of actually really building a Lemsteraak I would get a plan from a professionnal designer that specialise in these kind of Yacht.

Right now, I talk and I dream about these boats because I am amazed at the features these boats have. They basically have all my wants!!!

Someone mention in a comment above that the tiller is probably heavy, I actually thought the same thing! My solution while thinking about it was to actually balance the rudder. Basically I am more inclined at using a submersible type of electric propulsion that would be integrated in the rudder with the propeller at the end of the rudder. It would help a lot for port maneuverability to be able to steer with the propeller on the rudder. Anyway by having this setup there is no need for the rudder to be chop for the place of the shaft and propeller from an traditional inboard arrangement. This way the rudder could be filling that empty spot all the way to the keel and it would make it a balanced rudder. It will for sure help to reduce the muscle needed to steer these type of boat without going for the wheel arrangement.
Yes it was me who mentioned that the rudder is muzzle work. Why don't you plan a nice holiday trip to Holland and hire a traditional sail ship from www.jachtwerfdezeeg.nl or from www.sailchartersneek.nl the latter one has lemsteraken, vissermanaken etc from 2 to 12 people. Born in Rotterdam millions of years ago, I normally fly twice per year to Europe and then stay in the Kaag dorp and hire for a few hours a boat or yacht there. Yes indeed I also have placed my electric propulsion in the rudder of my electric boat. Good system. Valery, nothing wrong with dreaming. Bert
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  #23  
Old 02-21-2017, 09:43 PM
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Angélique Angélique is offline
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Maritiem Digitaal is a Joint Database of some Maritime Museums in the Netherlands.
Among other things, they have about 4,000 plan sheets online there, among the ca. 121,000 drawing info I saw there . .

The boat at the bottom of post #6 could be there compleet, if you can't find it I'll take a shot at it, when I have time . .

Some rough shots already ---> VA 18 - De Groene Draeck - of Bea - the former Dutch Queen -

Groene Draeck =306 results - Groene Draeck need images = 105 results - Groene Draeck need plans = 30 results - Groene Draeck need plan drawings = 30 results
- see the search box in the upper right corner for the Dutch search term I've used there -
You can drag out big images there, for example ---> W 10,000 x H 7,168 pixels.

Quote:

- - - - - - - - - - -^ W 1,000 x H 716 pixels ^ - - - - - - - - - - - click drawing to enlarge ---> W 2,000 x H 1,433 pixels - - - - - - - - - - -


'De Groene Draeck Zeilplan'. Zeilplan en details: tuigage aan de voet van de mast, smeerreep op de giek, de masttop, de raktouwen en een talie.

Afmetingen: lengte 15 meter, breedte 4.50 meter, grootzeil 73 m², fok 31.5 m², kluiver 30 m², botterfok 47 m², jager 92 m².
Will answer the question about ballast in more detail later, when I have more time, for starters Lemsteraken do have a lot of build in ballast nowadays, since they don't have to carry a shipload of fish home anymore, carrying ballast has much improved them . .

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

P.S. - Edit - added: - Adaptation of the picture size goes here as follows, see below the URL of the shown picture in the quote, which shows up as W 1,000 x H 716 pixels.

http://mmr.adlibhosting.com/madigopacx/wwwopac.ashx?command=getcontent&server=Maritime&value=fsm%2Ffsm_213%5Cfsm-1999-244-b%2Ejpg&height=1000&width=1000

Adaptation of the picture's size here: set both red numbers in the same value of the desired width, max is 15000 or so, which gives a picture of W 15,000 x H 10,752 pixels.

Note: the picture is blown up this way, and thus becomes blurred when too much bloated, like in the last example, and moreover, the image then becomes kinda unstable, at least for me. So max about 1800 works fine for me in this case, one and another of course in the first place dependent on the quality of the image as found . .
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Last edited by Angélique : 02-28-2017 at 03:53 AM. Reason: added P.S.
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  #24  
Old 02-21-2017, 10:48 PM
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Angélique Angélique is offline
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Note about the above Maritiem Digitaal links, just saw there's a button for English, approx at the upper right and bottom right of the webpages . .
But beware, there could be less info available in English, as this is often the case when foreign languages are offered . .
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  #25  
Old 02-22-2017, 06:08 AM
valery gaulin valery gaulin is offline
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Wow this is awsome, thank you so much! There is so much information in this Maritime museum. I can't believe how much wealth and informations the Nehterland is keeping in this meseum. Such a rich naval history, I am so amazed.

Thank you very much for taking time to share this info.
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  #26  
Old 03-03-2017, 05:24 PM
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Angélique Angélique is offline
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Just came across a Lemsteraak article in English . .
Yachting World ---> Extraordinary Boats ---> A new take on a Dutch Lemsteraak July 21, 2016
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