Directional stability at low speed

[dhaglund]

I recently started using my Zodiac Futura for fishing. It works surprisingly well! I appreciate the flat aluminium floor, it is a very stable platform to fish from and it is easy to reach the fish.

The problem is when I use it for trolling. The steering needs constant attention to go in a somewhat straight line. In any kind of wind or waves, if I let go of the tiller for more than a few seconds the boat will swerve a lot in some direction. Note that the tiller stays put, that is not the problem. This behaviour is not very practical when fishing. Because sometimes I need both hands for other things and sometimes I might even catch a fish and I don't want to take in all the other lines.

Do you have any tips on what I can do to improve directional stability when going real slow (1 - 1.5 knots)? I was thinking about dragging a sea anchor or something similar.

[Max...]

Tried tightening up the autopilot? Is this weather inflicted, ie gusty? SIBs are big balloon’s floating on the surface making very little way and very susceptible to wind,

[dhaglund]

Originally Posted by Max...

Is this weather inflicted, ie gusty?

Yes, wind or waves will cause this.

[Max...]

Not much you can do really at such a low speed - consider the tide and wind will typically be much more powerful that 1.5 knots, no keel on a SIB, no grip on the water = you're at the mercy of other forces.

[dhaglund]

Originally Posted by Max...

Not much you can do really at such a low speed, you're at the mercy of other forces.

Well, yes and no. The forces will inevitably try to push the bow off course when going against the wind in any direction but exactly head on. Unless you could even out the forces...

Let's imagine that I would be using a bow mounted trolling motor instead of the rear mounted outboard. Then the forces would always push the rear of the boat so that the bow would point directly into the wind. It would be the same problem but the other way around. Now, let's imagine that the propeller is mounted in the centre of the boat. Then the front and rear forces would be more balanced and the whole problem would be lessened.

While is is very impractical to mount the outboard in the middle of a SIB it is easy enough to "lengthen" the boat using a drift anchor to accomplish something like it.

Today I tied a large plastic bucket to the outside rear handle of the boat. One on each side and gave it a try. That worked somewhat. Turning became hard. But the buckets sometimes floated randomly in relation to each other causing a sudden small turn, so it wasn't ideal. Instead I used only one bucket and that did the trick! I mean, my SIB doesn't handle like a 30 ft sailboat or anything like that, but it's a whole lot better than before. With just a length of rope and a bucket!

[dhaglund]

I've spent many hours trolling this summer. The bucket swerved unpredictably sometimes, perhaps a few holes in the bottom would have helped? Regardless, this is what I use now. A Pelican case that has a few holes in the sides and a couple of kg weight inside works pretty well.




I still wish I a front-mounted trolling motor with auto-pilot but until then this will have to do. At least it is better with than without. I just toss it in the water and drag it behind me. I also helps to keep the speed down when using the main motor.