Warren,

I suppose you want me to weigh in on this....

You're right, the equipment durability is not an issue.  They are used at emergency scenes by firefighters - a group not known for grace and tenderness with regards to equipment.  See definition of "Firefighter-proof"

Defibrillators decidedly do not float, which hopefully is not a factor, but with a $1000+ price tag, might be reason enough to insure them - just in case.

Using an AED on a recently rescued rower is a big logistical problem.  Remember how we always did the "I'm clear, You're clear, Everybody's clear!" before the shock so no one else would be sparked?  Imagine how hard it would be to dry off a rescued person in the bottom of your launch, so the electrical impulse won't be transmitted.  This is not an instance for half-measures.  You do not want to be wrong about this when you hit the "shock" button. To wit, if you'll consult your manual, they are very specific and state repeatedly that AED's cannot be used in water. 

Similar effects can be expected from metal boats.  The aspect of conduction raises a lot of concerns/challenges.

Okay, so you're superhuman and you dry the person off front and back (and remember if you're going to use the AED, said person will not be able to help you do this).  You get the victim/patient/rower in the bottom of your launch so you have a firm surface to compress the chest against.  AND you prove to be the mighty CPR god that I know you are.... The current AHA protocols emphasize "Early Defibrillation" over "Early CPR", meaning if you have the equipment available you for sure want to use it. 

This rescue can be a one-person show up to this point, but you'll still need someone to drive the launch to shore.  You cannot do one-handed CPR and drive the launch with the other.  My feeling is if you're involved with a CPR or CPR-AED incident while you're alone in a launch, you need to shanghai a driver between sets of compressions or while the AED is analyzing.  Maybe another sculler or someone from a larger shell, or even another motorized boat.  Get loud and get help.  Remember the best outcomes result with effective compressions and appropriate (read, early) defibrillation.

If you are really all by your lonesome, beat feet to shore and begin emergency measures as soon as you reach the dock.  Don't waste time trying to get the victim out of the launch.  In this case, you want to be sure that you've left your cell phone on, so you can direct emergency responders to your location and advise the 911 dispatcher how things are going.

So to the point:  I think they're a good idea -- in cases where there are two people in the launch and a supply of emergency supplies, like a backboard and blankets, to address the water in the bottom of the boat challenge.  These circumstances are more likely to come together in instances when we're officiating at a regatta rather than the more solitary coach-on-the-water scenario.  To this end I have purchased a backboard and straps for my launch and outfitted the first aid kit with pocket masks. The next purchase will be a radio console and then the AED.  Once I get it all together we'll have a training session, because the only thing worse than not having the right emergency equipment is having the equipment and no one knowing how to use it.

Sheila

Firefighter-proof:  Put a firefighter, naked, in an empty room, with no doors, windows, or furniture of any kind.  Give him two marbles.  He'll break one and lose the other.

Anything that is firefighter-proof cannot be broken or lost (but this really just applies to planets with discernible gravity...)