The back is the shape of a very old submarine, which I hope to God stays above the water.

"Shaftoe has found the remains of an old Nipponese submarine."

I haven't heard anything about them being back-fitted on the older submarines, and I'm not sure they have the power supply for it.

In contrast, older submarines must steam some distance to get within range.

She could be the oldest submarine in the world still afloat.

This is an old submarine, and it could spring a leak.

After the Devilfish incident, the dolphins were practically all that he had left from his old submarine.

When finally decommissionned in 1992, she was the oldest submarine in service.

At the time she was already the oldest submarine in service with the Royal Navy.

It is a well documented fact, Alex, that these old submarines represent the single biggest threat to the world today.