Quick pole spear try

My son has been dying for us to try our hand at building a pole spear for him to use around Wood Guy's place this summer, so today we gave it a shot. Not a home run, but useable, and we learned a few things.

The construction is two layers of carbon fiber / blue fiberglass sleeve over a 1/2" PVC pipe. We turned pieces of PVC for each end, which we glued in place with standard PVC cement. This isn't a big game spear, and we figured the PVC cement should handle the flounder or small mangroves. On the business end, we threaded the shaft and screwed it into the PVC end piece. It actually screws in further than the threaded area on the shaft, so that the shaft is the full 5/16" thickness at the entry. Overall length is 5', and the diameter is just over 7/8".

Things that went well:

Hanging it from the ceiling with a weight kept it nice and straight.
The heat shrink left a perfect finish. Zero sanding.
The threaded shaft can be removed, but it's a tight threaded fit. I don't think it will come loose unintentionally.

On the downside, I would have liked it to be stiffer. The composite layer is less than 1/32" thick. We considered ordering a few more sleeves to add thickness, but the 10 year old member of the design team was anxious to see the finished version . . .

Dan - Might need to hit you up for a couple floppers and pins if you still have some.

Some pictures would probably help, so I made a little cut away model.

A standard tap has a tapered nose, and therefore does not cut fully formed threads all the way to the bottom of a hole. Because of this, a threaded shaft, screwed in completely, will jam itself into the area at the end of the hole where the threads are incomplete. Maybe not the best idea with metal to metal contact, but a stainless shaft in a plastic bushing ends up working like one of those lock-nuts with nylon inserts. It can be removed, but it's very tight for the first full turn or so.

Secondly, you can see from the cut away model, that we drilled out the threads near the openning of the hole. This allows the shaft to remain its full diameter at this point, which is where any bending stresses are greatest.

If you ever need to cut threads very nearly all the way to the bottom of the hole, ask for a "bottom tap", like the lower of the two here:

The threading in the cut away is only about half as long as in the real thing. The gray material is PVC, which is pretty strong as plastics go.

This one is admittedly a prototype, just to try a few different approaches. But I think the connection could be made quite strong by making the whole arrangement longer, and providing for lots of threads, with a substantial length of unthreaded shaft inside the plastic.

We got a chance to try the polespear out last week. In total, my son took 7 flounder from the boat in shallow water at night, and I shot one nice 7+ lb sheepshead at a shallow inshore bridge rubble reef. I did learn a couple of things.

First, I have a new found respect for anyone who can consistantly hit fish at any signficant distance with a polespear. I routinely missed them at just a couple feet.

After bouncing a few shots off sheeps the first day, I ground a small tri-cut tip on the first 1/3 or so of the spear point. That made a very big difference in the penetration the second time out.

Needs a stronger band. The little 5/16" OD by 1/16" wall band just wasn't enough on larger sheepshead.

I also found that this spear floated with just the last 3" or so above water. My son doesn't dive with it yet, but I like the idea that it will float if dropped or lost.

It is not very common to have inshore visibility good enough to freedive that particular reef, but I'll be back whenever the conditions allow. Lots of fun!