Fra planke til fiskepinne

From plank to fishing rod

In the coming week we will look at how to make a control vane which is used to control the harpoon and which reduces and controls the recoil, stabilizes the aim and improves precision. The new harpoon for which I am building a wing has been given the official name: Doomsday Harpoon. If the fish had a newspaper they would write about this.

By Simon Krüger, September 2012

In the picture you can see that the wing on one harpoon is twice as big and the muzzle has been extended and has a better arrow groove. The modified wing does not give worse dive times as it is more streamlined and weighs more. The weight means that you use less energy to break the surface and controlling the properties of the water helps you save energy. On the way up, it is good to drag the harpoon behind you from a distance and use the dead weight to steer with so that you save energy on the way up. The straighter up and down you swim, the more energy you save. Since the harpoon is extra heavy at the tip, you can save some lead which also saves energy when swimming. When you sink without having to swim, you use the wing to steer.

A bit about accuracy with a string harpoon

On a rifle, the cartridge will leave the barrel before the recoil takes effect. In a similar vein, I would argue that new fast bows that pull well from the beginning send the arrow off with less effect from the recoil. You don't have to agree with the theory, but put new stitches on your old harpoon and see if you hit better in practice. Old, tired knitwear loses a great deal of effect when it has been strung up for a while. One possibility is, of course, not to swim for 6 hours at a time with the harpoon cocked. Take care of socks and mittens so you have them for a couple of seasons - then you can rather spend the money on changing the elastics annually. Knitting is a consumable item.

A standard harpoon with moderate power and the handle placed high and at the end of the harpoon has the prerequisites to hit quite well at up to 5 meters. A more powerful harpoon that can penetrate a lyre of 9 kilos at a distance of 7 meters will have more recoil due to the heavier arrow and a more powerful mechanism which means that the handle is placed further down below the harpoon.

In order to be able to turn a more powerful harpoon more easily, it is often designed with a Midd Handle, which gives the recoil even more momentum when you have to use several strings to send the powerful arrow off. Therefore, the metal tech harpoon from Riffe is known to be quite imprecise. A video recording showed that by the time the arrow has left the harpoon, the tip has been lifted 10 cm. It means in reality that the arrow is thrown in a ballistic arc forward.

In addition, the harpoon is pressed against the hand with considerable force and the moving parts of the arm lose the fight. The thumb and elbow bend and the harpoon turns towards the axis of the body. If you use your right hand, shoot 20 cm to the left on 5 meters with 5 stitches. During shooting training, I have noticed that you can get used to the ballistic bow and hit the height quite well, but how far the arrow is pulled to the side depends on how well your muscles absorb the recoil and this then becomes quite unpredictable. Eventually I decided to change to a lighter arrow and build my own steering wing.


Before you start, you should know that you risk damaging your harpoon if you drill in the wrong place. The wing must be finished before you drill into the harpoon. You should also know that it takes a LONG TIME to work with hard wood. Use a quality jigsaw with a quality blade that is sharp. The blade goes in all directions if it is not sharp enough. When you drill, you must take your time and regularly release chips - otherwise the drill will get hot and crack inside the wood you are working with.

Split a hardwood plank into two equal pieces. My wings are 5.5 cm wide and 36 cm long. You can certainly make them half as long and narrower.

Everything must be straight

Find the points where you want to drill screw holes on both the harpoon and wing. Draw a thin strip to mark the center of the drill holes and first make a thin drill hole by drilling gradually from both sides. You are of course privileged if you have a table-mounted drill that can do the job with precision. It is easier to drill holes while the wood is square.

Saw away wood in straight lines first. After this, you can better twist and turn a jigsaw and get a precise cut.

Compare with the dimensions of the harpoon. Consider weight distribution and other factors. In this case, a soft strip should be made to cover the groove on the side of the harpoon.

The shaded areas must be sawn away and polished


Now is the time to make recessed screw holes and shape the wing. The underside is mostly flat to give forward direction and the upper side is curved to be able to easily steer down and to the side.

Now it is very good to have a precise transverse steering hole that the tip of this can follow.

You can use a steel saw and grinding machine and make Syrefast 6mm screws in the desired length. A polishing machine with sand paper works well, while a sander easily damages the grooves.


Now it's time to grind. This takes time with hard wood. The dust and sandpaper or wood particles can fly off with extremely high force and hit you or others. Use protective equipment.

Fine sanding with sandpaper, coarse, semi-rough and very fine. The sander creates scratches and pits in the wood and these must be sanded away. Take the time you need as even the smallest mistakes will be visible. You are welcome to use a gas mask with a particle filter and suitable protective glasses. I use a pair of old ski goggles that close tightly and stop dust quite well. The sander is made for floors, but at maximum revolutions it has a very large effect at the edge of the sandpaper. You can use it as an angle grinder on wood.


Screws are finished and holes are to be drilled in the harpoon. There is an advantage with a table-mounted drill.


Now it's time for 2 component glue. I use araldite and basically don't know of alternatives. Araldite hardens within minutes. You must proceed schematically and be quick and precise. Take a small batch at a time and keep the glue warm so it runs quickly. Mix up small portions of glue at a time. Glue that has started to set is slower to work with and this is precarious when the glue is setting and you are working against time. You need something about the size of a teaspoon to mix and apply glue quickly enough.

Float wings usually do not have to be glued on, but this harpoon has a deep and high groove on the side which means that it can be difficult to get it close enough. The space between the screw holes can be filled with glue to make the harpoon massive and dampen vibrations.

Get everything ready and have a system of where you have things.

The harpoon is ground down where it is to be glued

Fill the groove on the harpoon with araldite, avoid glue close to the drill hole and do not apply so much in the height that it protrudes above the wooden surface, since the glue hardens before you can attach the wing.

Put the screws with locking disc in one wing and apply glue to the wing where it is to be attached to the harpoon without gluing the screws.

Drive the screws through the harpoon from the bottom up - place the other wing at the top and tighten the screws while the harpoon is on its side at the appropriate height.

Now one wing is glued and if there is glue on a screw it is in the right position. Avoid glue on the nut and locking screws on the wing, which are glued on first. These screws will come off later so you can fill the cavity with glue if possible.

Remove excess glue with a lint-free rag. Start by drying the upper side of the wing. You can use a little alcohol. Alcohol dries out the wood. After at least two days, you can sand away dried glue with a sanding machine. Use a gas mask with a particle filter.

When you have cleaned off most of the glue with a lint-free rag, you can turn the harpoon over and repeat the routine. Before putting on the screws and locking the disc, you can fill the screw holes with glue. Check that the wings are in place and use the screws or loose screw clamps to hold the wings in place while the glue dries within half a minute. The most important thing is not to get the screws on but to check the position of the wings. If you can't get the screws on because of glue, it's not that important. The screw holes can be sealed anyway.

Now the wings are where they should be. When the glue is dry, remove the screws on the first wing and fill the gap with fresh and slightly liquid glue. You may run the risk of glue running through, so put some cardboard on the ground.


Apply bulk glue in the screw holes with a caulking gun. When it starts to solidify, you can scrape with a rubber scraper for tile laying. Let the glue dry for a day before sanding away any remaining glue.


Remove excess glue with a sander. Fine polish with what is needed of sandpaper.

Now you are ready to oil the harpoon. Feel free to use vegetable turpentine before the first two coats. Remember that turpentine can spontaneously ignite. Store rags and paper outdoors or in a fireproof bin.


The harpoon is now ready for the installation of knitting, spear and line. A more detailed description follows. Now the harpoon will be tested in the sea!

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