Frank, aside from the fact that stun grenades are pretty much illegal to possess for civilians (in or out of the US), you wouldn't want to set one off in close quearters. Unless you are conveniently masked and protected--all you will do is stun yourself along with the attacker, who will REALLY BE PISSED AT YOU when they can see again.
Similarly, the throat strike (which crushed the larynx and obstructs the wind
pipe) is an easy kill, but it kills by suffocation, so the attacker will typically have two to four minutes to be REALLY PISSED AT YOU while they are dying. Unlike Hollywood, these things must be considered in real life. Two minutes with a machete, and that dying attacker can still do a lot of damage. (Machetes from China
cost about a dime, and sell for about a dollar, in much of the undeveloped world.)
A nasal strike, using the open palm to drive the cartilege of the nose up and back into the brain, may kill instantly. Or, it may just break the nose again leaving the attacker [chorus] REALLY PISSED OFF AT YOU.
The problem for the untrained, unpracticed, or reluctant victim, is that whatever you do--you don't want to leave the attacker really pissed off at you. That's probably the worst possible thing you can do, worse than submitting, fleeing, or fighting.
Cheapest protection? Solid locks on the companionway
boards and hatches, to allow ventilation but prevent easy entry. Just in case the Guardian Angel is off for the night.<G>