Van der Valk 20kts low power aluminium/steel semi-d designs.

A1GSS said:
Well yes. I came very close to buying one in 2002 when the world was different. Lovely things. The Dutch are the masters of this in my view. If you browse eg the dutch broker websites (eg http://www.devalk.nl/) you can get an idea of the scope.
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The finish on Dutch metal boats is extraordinary , not a ripple in sight; They have mastered their craft to the highest level attainable. I've always associated them with displacement inland waterway boats and barges, and massive seagoing displ super yachts .
 
That's right, there are a few semi-displ offerings though eg that WVdV range, Linssen did a couple. Mulder. Alu more costly to build but much lighter obviously so powering is cheaper for same performance.

Not steel but Elling is in the same mould, pun intended.. :)
 
rustybarge said:
What's the minimum planing speed, approx displacement?
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I'd say around 17kn maybe slightly less but not less than 16.
12tons measured based on the calculations of the displacement (no other means to do so here)
Engines replaced from original DD so approx 1000kg less than originally setup and balanced, stern is higher than it should.
length 12.90m without the bathing platform, WLL just over 10m iirc.

V.
 
vas said:
I'd say around 17kn maybe slightly less but not less than 16.
12tons measured based on the calculations of the displacement (no other means to do so here)
Engines replaced from original DD so approx 1000kg less than originally setup and balanced, stern is higher than it should.
length 12.90m without the bathing platform, WLL just over 10m iirc.

V.
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Very similar numbers to the semi-d hulls we're considering here in weight and transition speed; plywood is very light and strong, but when all the engines and equipment are added the displacement soon balloons into normal range for a similar GRP boat.

Actually your boat has a passing resemblance to the hoek 60'; those angular chiseled looks which have become very fashionable lately.

 
While we wait for some nice construction pics from Yoeri at v.d.Valk, I've done some ' back of fag packet ' calcs to get some idea of the numbers....

To set down a real world bench mark for fuel consumption at displacement speeds I've refered to the Dirona Nordhaven 52' circumnavigation blog where they have averaged 1.3mpg @ 6.5kts over 30,000 miles at 40tons displacement.
US gals: nm distances.
6.5kts/1.3=5gal/hr
5galx18hp=90hp on a 40ton boat=2.25hp/ton for 6.5kts cruise.

V.d.Valk 16m 30 tons x 2.25=68hp or 3.8gal/hr or 1.7mpg@6.5kts.
25hp/ton @ 15kts= 750hp/18hp=42gal/hr or 0.36mpg @ 15kts.

Bruce Roberts 45' 20tons x 2.25=45hp or 2.5gal/hr or 2.6.mpg@6.5kts.
25hp/ton @15kts=500hp/18hp=28gal/hr or 0.53mpg@15kts.

Wow! That extra 10' costs......
 
Last edited:
Goodmorning all,

Sorry, I was not notified by the tread, only after Peter's DM.
I will have a look what I can find (photos) on this particular hull/project on our servers.

Will be back soon.

Y.
 
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