crossgrain

Hi and thanks very much to all for the info here. I hope the thread and Sea Wolf will keep going for a few years yet. Shame it is no longer in production.

I was looking for a submarine as a present to a grandchild and came across an unused Sea Wolf on uk eBay. It was hard to find much about its workings except for two or three videos on YouTube, but these pages have been very useful.

Anyway I have just been to collect it and found it had its leaflets and box, all in virtually mint condition, and could check that it had the right bits such as the two types of ballast, and that the main rubber sealing cap was intact and not perished. Its history is that it was purchased about six years ago and from the look of the battery compartment it had never even been tested with batteries.

With 2300mah C and 2100mah AA NiMh batteries installed, it needed 6 ballast discs, and 13 small weights down the rearward end of the compartment, in order to balance on the deep side of the markers. Lateral balance only needed one small weight on the right to make up their odd number. My example had the charging socket location blanked off although a label referring to recharging was still present.

The hold-down hatch for the internal batteries is not very robust and it needed a bit of checking to understand how the tabs fit and to locate it so the latch could be closed without forcing something. The heavier sprung negative contact for the C batteries needed squashing a bit so as to avoid distorting the hatch too much, and the similar AA contact had to be opened up to make things work. There was a leaflet included to clarify this and labels were present to show which way round the batteries went.

I thought the instructions were good, although the way the ballast rings fitted could have been clearer. It became obvious there is no need to unscrew anything to get them on but, if you do, I found that the prop-retaining washer has slots in it which need to be lined up with tags on the prop (or was it vice versa?).

I did not take anything apart to discover the magnetic drive couplings etc., which I just read about here, but everything seems well worked out, such as the end bearing/support for the prop and I am not surprised that this model can keep working for years as people have reported. As a child I had an aluminium Triang speedboat with a much cruder electric motor which was indestructible, until I took it to pieces.

I seem to have picked up a couple of bits of misinformation somewhere. First, that the motors operate spontaneously on and off to balance the sub and, second, that there is a variable volume device or to stabilize it a different depths. In fact the motors only operate unexpectedly when the receiver is swamped by holding the transmitter too close and, although there is a buoyancy ball in the bows, this is presumably just to stop it disappearing, along with the sealing cap, if it falls in. I doubt if the sealing cap would flex much to have any adjusting function at the normal 2 or three feet operating depth.

The proportional controls for rudder and motor speed are a luxury and make all the difference but the functions are otherwise commendably simple. The introduction claims only two channels but it has three when the independent dive motor control is included, even though it is just on/off via the button on the transmitter. It seems a good safety device for the dive motor to stop working when radio contact is lost, to prevent the sub from sinking to its doom or from disappearing for ever in the murky depths! Unfortunately, if water gets in I guess the marginal positive buoyancy would probably be lost, with the same result.

I have only tried it in the bath, and claimed it was 'to make sure it works to avoid disappointment', but its size and appearance are quite impressive, with good steadiness in the water and scale-like speed and movements to fire the imagination. Pity it does not steer in reverse but I must try not to keep playing with it.

By the way, could you explain how some submarines use a pump or 'syringe' to alter buoyancy - once air has been expelled to dive, how it the water replaced with air again to surface?

Regards
Chris