December 14, 2008

Tritium on my mind

I AM VERY good friends with my old hand bearing compass. I use it constantly when I'm out cruising. It lets me know if I'm going to hit an island, drag anchor, or run into a tug. But like most friends, it's not perfect. In fact, it worries me sometimes when I think about it.

I've had it about 12 years now. In its heyday it was Practical Sailor's overwhelming best choice in hand bearing compasses. That's because it has "deadly accuracy and long-term reliability." It also has something else that Practical Sailor didn't bother to mention. It has tritium.

Now some of you may recall that way back in the Dark Ages they had X-ray machines that you could peer into when you bought a new pair of shoes. If you wiggled your toes, your bare bones showed how much room there was in the shoes for your feet.

I don't know what alerted the shoe stores – probably people's feet falling off, I guess – but suddenly all those X-ray machines disappeared. We began to understand that it wasn't such a good thing to expose human feet to so much radiation.

Now, my compass is a far fetch from those old X-ray machines, but it does have similar properties. It uses tritium to make it glow at night. I wouldn't have known that important fact if it weren't for a flea-sized notice of the back that says: "Contains tritium H3."

My curiosity changed to alarm after I got out the dictionary -- "tritium, a radioactive isotope of hydrogen … decays by beta-particle emission and is used in thermonuclear bombs."

So now I'm very nervous when I take a bearing with my nuclear-powered compass. I don't hang about. I can take bearings with lightning speed. Every time I raise that compass to my eye, I can just feel those radioactive beta particles cruising along my optic nerve to my brain.

One day, when enough of them have gathered, there's going to be a nuclear explosion in my head. I can only hope, when that happens, that I'm standing very close to Practical Sailor's compass evaluator.

Today's Thought
We only part to meet again.
Change, as ye list, ye winds; my heart shall be
The faithful compass that still points to thee.

--John Gay, from "Sweet William's Farewell to Black-Eyed Susan."

“Jeez, my wife gets historical every time we have an argument.”
“Historical? Don’t you mean hysterical?”
“No she keeps dragging up my past.”


Jeff said...

Mr. Vigor,
I happened upon your post and work in the environmental remediation field. For what it's worth, I think that you can rest soundly regarding the tritium in your compass. My guess is that the tritium is in the paint, which is also submerged in water and separated by a plastic or glass barrier. I've included a link to a fact sheet if you're interested, but the jist is that, "Tritium poses a health hazard only if it is taken into the body, because tritium decays by emitting a low-energy beta particle with no gamma radiation. This betaparticle cannot penetrate deeply into tissue or travel far in air."

You can get sunburn-like effects from direct exposure to beta (shine on your skin) which could affect eyes, but I'd lay odds that the levels in your compass are so low and separated from you that it's no concern. Take your time sizing up the horizon.



Phibius said...

Just for extra reassurance, consider the little-known hormetic effects of low doses of radiation ("The Healthy Worker Effect and Nuclear Industry Workers"). Potentially, your beloved hand-bearing compass may actually be making you slightly healthier, and not just by helping you to stay out from under container ships.