HOLLOW ENTRY January 30, 2011 | Read » THE HYBRID PROJECT | Read » BLUE SKY

When being a practical person, it is sometimes useful to bring around people with a bit more theoretical approach to challenges in life, to have their opinion on my thoughts and ideas.
So when boat designer Fredrik Graven popped up during our visit in Rognan we could not resist challenging him on the subject of a sailpowered fishing boat – for the moment being materialized in the first prototype called the Hybrid. Fredrik took part during some of the talks between Kai the boatbuilder and myself during our first visit to Rognan.
One of the things of concern is the question of what happens with the wet surface when the boat is healing over, particularly during up wind sailing. Does the asymmetry of the wet surface create a constant wish in the boat to turn away from it course? And If so, does the helmsman need to compensate this by using the rudder to turn a bit the other way ? And if all this is the case — how much drag will this actions by the boat and the helmsman cause?
Drag is a drag – that’s for sure.
So basically we wish to dwell around this question a bit and see if we can play around with the shape of the hull, particularly the forward part, to hopefully compensate or ideally avoid this effect.
On key factor in this respect is the so called – hult innløp – or “hollow entry” of the hull which is quite characteristic on a Nordlandsbåt but not at all evident on a modern racing hull shape, which is normally more beefy in the water entry forward on each side behind the bow.

There are so many factors involved in this matter that I always think that at the end of the day I have to make a compromise choice based on some kind of gut feeling – which again of course is also a matter of digesting all comments and opinions being thrown at me during the process of consideration.
This is part of the fun and of course I never exclude from the process of decision making sure that the end result also will balance well visually – before I can decide to go for it.
Anyway these are some of the thoughts that are flying in the air these days – among a lot of other things happening.

Drawing on the left by Eilert Sundt shows well the hollow entry on the old nordlandsbåt, and the picture on the right illustrates the more bulky entry on modern racing hulls that gives a good volume and lift, but which again might create an aggressive angle of attack for the entry of the water flow along the hull. It all comes down to a compromise and personal preferences.

Covering the sketch model with gladpack gives a good surface for playing around, drawing lines to illustrate the hull shape and the underwater wet surface while heeling over. The asymmetric wet surface shape can easily be detected.

Boatdesigner Fredrik Gravem came up with this interesting 3D drawing illustrating an attempt to integrate a classic hollow entry to a modern shape hull. Thank you Fredrik.



So much for theory. Let us wait and see untill we start playing in full size. Kai is busy with some other building and repairs these days
so I need to be a bit patient before we can dig into 1:1 thinking.
But at least we have agreed that the Hybrid will happen, and that is good news for the spring.
Thats all for now – stay tuned. —-jan

THE HYBRID: FIRST MOVE January 16, 2011 | Read » THE HYBRID PROJECT | Read » BLUE SKY

AND WE GOT REAL WET

Today we write 16th January 2011 and we are back in the south after a good month in the middle of the long winter night of Lofoten. Before the return Runhild and I visited Classic boat builder Kai Linde at Rognan which is one hour on the train south of Bodø. Kai is the man chosen to be responsible for putting together the wooden hull for the Hybrid – the first small scale prototype for the Sailpowered Fishing Project. Kai is a good old friend so it didnt take long before we got into discussing the real matters.

Short after our arrival we agreed to meet the next morning at the local swimming pool to do some underwater studies of the small scale boat models we had made before we met. Kai had made a special agreement so we would have the pool all to ourselves. We went to bed early and the stars were shining bright outside the giant window in the loft room over Kai´s workshop. A little childish excitement is always good.

As we had not prepared to go swimming that weekend we had some fun putting on some borrowed swimwear and I found my trunks twisted around my knees after the diving into the pool next morning.
I had brought my G11 camera with a waterproof box so we felt quite professional despite looking pretty funny running alongside the pool towing our models at planing speed.
It was surprisingly interesting to watch the boats from underneath, something I never have seen before and we got real inspired and what a nice way to do scientific research. What we saw and felt during these exercises gave us an excellent starting point and a good basis for all the discussions we had during the next two days.

In the afternoon an old apprentice (student) in Kai´s workshop Fredrik Gravem, who later became an engineer and boat designer came around – and we all three had an interesting day discussing quite openly about the whole idea of making a modern style racing hull design, in classic wood, clinker style.
Our main challenge is to make the hull strong and not too heavy to be able to perform according our expectations we wish to have from a hull-shape made for planing speeds. We understand this will be a challenge and of course also a compromise.

I have decided to have this prototype hull made the classic way,as a clinker in wood, and the reasons are not only to honor those people who through generations gave all their energy and skillpower and often their lives – to develop these boats into perfection.
But that could well be reason good enough alone.
One other good reason is that a clinker hull with a nice shape make me weak in my knees- just like my Nordlandsboat Misvær Marit does to me every time I see her.

She is like a woman, Ferdinand Porsche said to me 20 years ago when I asked him what was so special about the 911 which he designed, and later became a great legend. She is like a woman he said — she is unpredictable. She can be run with the feeling of perfection in hand – but at the same time you never feel sure about her. She will always challenge you – she will never let you rest. But you love her.
Kai and I agreed on many important matters that weekend and there are still many more to be discussed and that is the joy with it all.

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PICTURES FROM OUR VISIT AT ROGNAN EARLY JANUARY 2011
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Easy talking in Kai Linde´s workshop. From left: Boat design theorist Fredrik Gravem, Jan, Kai Linde and Dag Pettersen, a curious journalist from local newspaper Avisa Nordland, who wrote a good little story about the Hybrid and our vision for Sailpowered Fishing.

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Kai and I discussing the shape of the hull and questions around how to adapt the clinker principle into a modern hull design, which is one of our major challenges.

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Model testing in the pool. To observe the model from a cod perspective was a true revelation and extremely fascinating with lots of fun included.

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Model testing. Mattis Linde follows fathers model in close up.

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Model testing. The wave pattern shows nicely at planing speed

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So this is where this project stands at the moment and more news will come as soon as new things will happen. Fredrick the boat designer has promised us some computer drawings and I will soon come up with more thoughts and details on the Hybrid progression.

take care
jan wanggaard

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