Van der Valk 23M in build

[Yoeri]

Dear all,

By the fact the last topic was more a discussion what to do or not to do, I'll start a new "fresh" topic, and introduce myself once more:

My name is Yoeri, I work for the Wim van der Valk company in the Netherlands.

Since the report by Dave Marsh in MBY September issue on our 23m Flybridge we have had a lot of interest and questions about Van der Valk boats. Many of the questions have been about the IPS drives, propulsion, manoeuvrability and the Aluminium Hulls and why are they are not built in GRP? As you all now, Aluminium is light and strong so allows us to build without the need for fixed location structural internal walls and bulkheads thus the owners get a free hand on the interior design of each and every boat.

Because of the emails and calls about the boats to our dealers and here at the factory we thought maybe you would like to see how we build them from
the ground up!

Here are some photos of the Aluminium parts ready to be constructed and welded together to shape the first section of the hull.

If enough of you would like to see the build progress we will happily post more photos and explanations of what's happening - would this be of interest to the Forum readers?

BR

Yoeri

 

[Yoeri]

Hi guys,

I have decided to just upload a new set of pics and explain a little what the casco construction guys are doing at this moment.

Just a few smart facts:

Thickness of the keel: 16mm alloy
Distance from the main ribs: 50 cm apart
Distance from the crossbeams: every 25 cm

Welds have a length of 7 cm and are put every 14 cm (generally).

The hull and superstructure consists of 3000 - 4000 several pieces of aluminium.
The aluminium pieces are not cut using a laser, plasma or waterjet cut. We have them routed. This is the only way to create a 100% secure 90 degree cut.

As you can see a huge progress has already been made. The hull is turned from downside-up to the usual way. Currently they are building the rafters/ribs on the hull. From that moment the hull will get more shape.

 

[Yoeri]

Hi Yoeri,
Thank you for giving us all the chance to see this Vessel under construction.
Time for a question.
How do you manage to keep it all in shape, with out any construction jigs, and avoid any distortion from the welding?
I just wish I could alloy weld like that all lbe it on a much smaller scale.

Dear old_salt

Probably it is not very well shown on the pics that these 2 bulkheads are secured in between the frame so that the welds are not forced in any way. In first instance (my first post) you probably have seen that the first part of the hull is constructed upside-down. This is much easier for the guys and they can give the bottom part of the hull a lot of stiffness and strenght before a lot of weight is added to the casco.

As my next post (with pics) will show they are now assembling various rib parts (side) per 12 pieces and they will be put on the hull next week.

I will try (because Bojangles is absolutely right about this) to answer all of the questions, but there is a chance that some answers are a bit delayed during the fact that I will be not in the office or have a very busy day (or something like that).

As I told before this thread is on my own initiative and thus I will not respond on a monday till friday base ofcource!!

Yoeri

 

[paultallett]

Hi Yoeri,

What is the expected build time, from the first weld to being ready to hand over to the customer??

 

[Yoeri]

Dear Paul,

Normally it takes about 11 to 12 months to complete a 23M from first weld to delivery. During the construction of the hull an owner can still make layout changes or even still decide the full layout because portholes can easily be moved (or even put just before leaving to the painting shed) without having effect on the strength and looks of the ship.

In this case it will take us about 10 to 11 months because we have like 6/7 casco builders on the hull and superstructure so we save like a month on the casco build time (what took us normally approx. 3 months).

 

[rafiki_]

Yoeri, how is the alu coated or finished to minimise corrosion, and galvanic reaction?

 

[Yoeri]

Dear rafiki,

We use AIMg4,5Mn - H321 / H311 aluminum which already is better resistant to any sort of corrosion than most other alloys.

After finishing the casco the complete casco is "fossil" sandblasted outside aswell as the inside.
After sandblasting a 2 component primer is sprayed on (inside and outside).

Finally (after lot of filling and sanding) several layers of a 2 component AWL GRIP paint system are sprayed on to guarantee that the ship will be free of corrosion.

Besides annodes and a separator device will be used to eleminate electrolysis.

Yoeri

 

[Pinnacle]

This is going to be a fascinating thread.

 

[old_salt]

Yoeri. Thanks for your reply.

 

[petem]

Hi Yoeri, what does 'casco' mean? Also, is there much other work going on in parallel (joinery etc, somewhere else)?

 

[newWave]

@petem : casco = the bare hull fully welded. (to be technically correct this would exclude the superstructure)

@Yoeri : How does the extention of the wheelhouse influence the balance and trim of the hull, placement of the stabs and so on ?

 

[wakeup]

Hi Yoieri,

I am still struggling to see the advantages of the Alu hull. Seems like a huge amount of effort. I guess you can go straight from cad to production?

It would also seem to me that with so many welds and parts used to make up the hull then statistically one or two will fail at any point in the future which is highly unlikely in a monocoque GRP hull.

Are there any other benefits? Weight vs GRP?

 

[MapisM]

First of all, since I forgot to mention in your other thread which drifted into forum principles: welcome to the madhouse, and thanks for taking the time to show us what you're doing and answer our Qs!

And apropos of questions...

Finally (after lot of filling and sanding) several layers of a 2 component AWL GRIP paint system are sprayed on to guarantee that the ship will be free of corrosion.

This is a choice driven by aesthetical reasons, I suppose?
I mean, wouldn't a simpler anodization be more effective than any painting, no matter how good it is, for corrosion protection in the long term?

 

[BrendanS]

My concern would always be that no matter how good the prep and covering, boats get gouges and scratches, and that the alu underneath would then suffer corrosion. However, big ferries are built this way, but if you go on the ferries from south coast to Channel Islands, they say the max speed is decreased through the life of the ferries as they take quite a pounding, so the speed they are allowed is decreased with each inspection. Though boats that size wouldn't be made with the materials pleasure boats are made of, and similar constraints would apply.

 

[Bajansailor]

Yoeri, thank you for posting this excellent first set of what I hope will be a long running series of photos detailing the construction of this fine motor yacht.

You mentioned that the aluminium parts are cut out with a router, rather than using a laser, plasma or water-jet - I presume that the router is CNC, by a machine according to a CAD drawing, rather than an operator cutting them out by hand with a router?

I am intrigued as to why you have to blast and paint the hull interiors - I thought that one of the major advantages of building with marine grade aluminium was that the aluminium could be left un-painted, with no corrosion issues or worries.
Even on the outside, above the waterline any paint used is more for cosmetic rather than protection purposes.

Re other boat building threads in aluminium, I posted a few threads (with some photos) two years ago re the OSRV that was being built by Alnmaritec (www.alnmaritec.co.uk) in Northumberland for our local Oil Terminal here in Barbados.
Here are some links - although our OSRV was an extremely basic vessel in comparison to Yoeri's, they also show some good examples of construction and welding.

http://www.ybw.com/forums/showthread.php?t=224851

http://www.ybw.com/forums/showthread.php?t=237131

http://www.ybw.com/forums/showthread.php?t=240767

In retrospect I should really have kept them all in one thread, like JFM's most excellent thread about the construction of his Fairline 78 'Match (link below)

http://www.ybw.com/forums/showthread.php?t=240351

 

[rafiki_]

Normally, when welding 2 metals, the weld degrades the integrity and finish of the metal, therefore needing additional finishing to bring back the corrosion resistance. Is this the case for VDV?

 

[Imperial One]

Yoeri is away until Monday now and I am sure will fully answer the queries himself. Naturally I can answer them myself but that would be to steal Yowei's thread - and I would not wish to do that.
I have a UK owner of a 20m Alu VDV boat that called me about three weeks ago to say he had just had the ride of his life in some big seas in the Swellies and had fallen off the top of a very big wave. He called to say the boat was simply brilliant and the only thing that happened was the radar had turned off as the sea went over the top of the wheelhouse and found the switch on the scanner! His previous boats have been VDV Steel and before that GRP from Atlantic (which I sold him) and before that a 58 footer plus smaller ones from a well known UK manufacturer. I will try to get him to join the forum and post of his experiences with the Alu versus GRP debate then it is entirely from an owners perspective.

 

[Yoeri]

Hi there guys,

Thanks for all the shown interest in the construction!

Regarding the welds, corrosion and alloy construction compared to fiberglass:

Welds
Some of the welds will be forced more than others. The 90 degree welds on the surface and the hull are forced the most through the momentum of the engines. Also the front part of the hull (the bow) is forced through the splitting of the water. With displacement hulls there are more forces than with a semi-displacement / planing hull.

On base of these knowledge we calculate what parts of the welds are exposed to what force and calculate what size the weld must be to strengthen the hull the most.

Casco
In our opinion (and the other Dutch builders) the casco contains the barebone hull and superstructure.

Corrosion
Bajansailor, you are very right. But we just sandblast and 2K primer above the waterline and the inside just to be 100% sure that these are 100% covered and this reduces the risk of corrosion to a minium. Pure security reasons. For these reasons, our ships are also extremely durable.

Aluminium compared to fiberglass
Besides the weight, which is comparable to fiberglass (our CII 23.00 Fly was just a little heavier than the Princcess V78) there are more advantages:

- As mentioned before aluminium is far more durable. This not only ensures that the ship will maintain a longer lifetime, but also ensures a much lower depreciation (longer economic lifecycle).
- Maintenance and damage are also much easier to work.
- We can do all sort of changes without any visible result during the casco building process (during the fact we build customs this is a huge advantage compared to a fiberglass hull which can not be changed after moulding)

Routing the parts
Indeed the parts are routed from an automatic CNC CAD/CAM system. This is a very precise process. Drawings are deliverd and after cutting the building process can start immediately. So this definately speeds up the process.

Extending the wheelhouse
Dear NewWave, extending the wheelhouse does not have a great effect on the balance or trim of the vessel. The small bit it does influence can be calculated and compensated with the full tank (which is over the complete lenght of the ship) or with ballast (if weight is not a big issue).


Yoeri

 

[paultallett]

Welds[/B]
Some of the welds will be forced more than others. The 90 degree welds on the surface and the hull are forced the most through the momentum of the engines. Also the front part of the hull (the bow) is forced through the splitting of the water. With displacement hulls there are more forces than with a semi-displacement / planing hull.

Wow.... I'd have always though a planning boat was more stressed as it made passage??

 

[Yoeri]

Hey Paul,

On the contrary. Pushing the ship through the water (because that is wat happens with a displacement ship) makes the forces on the hull more intense. At least in certain parts (most likely the bow part of the hull)