How (Not) to Cook a Hand Grenade

Never, ever, "cook" a hand grenade. The fuse is supposed to be four seconds and was made by the lowest bidder. 

- USMC Instructor c. 2003

Listen up Marines, this is how you "cook" a grenade.

- USMC MOUT Instructor c. 2008.

 

Grenade Chef

"Cooking" a hand grenade means releasing the spoon and holding a live grenade in your hand before throwing it, in order to run the timer down so that your enemies can't throw it back. GURPS High-Tech p. 190 has rules for this. These rules have a number of problems.

Firstly they say the thrower takes two Wait maneuvers. Why Wait? Wait is a maneuver where you specify a triggering condition and a response to that trigger. These "Waits" don't have any triggers or reactions. All maneuvers take one second, so it really doesn't matter which one you take here (as long as it isn't throwing the grenade).

Secondly is that it's mostly risk free (assuming you don't drop it). It assumes you can accurately count two seconds under fire and that the fuse works exactly as advertised. These assumptions are pretty dubious. 

My fix is: 

The thrower takes two Concentrate Maneuvers (they are counting) and makes a Soldier roll. On a critical success it explodes immediately after you throw it. Success means the grenade explodes in two seconds, failure means you threw too early and it explodes in three seconds. A failure by four or more means you threw too late. Subtract your margin of failure from the range, this is how far it gets before exploding (minimum 0, which means it explodes in your hex). On a critical failure it explodes while you are holding it. This does maximum explosive damage to the thrower and one automatic fragmentation hit to the hand.

The Whole Throwing Back the Grenade Thing

GURPS makes throwing back hand grenades pretty easy (B410), one turn to kneel down, one turn to Ready the grenade and one turn to throw it back. With a four second timer this means that the original thrower has no chance to not get blown up themselves. In real life throwing grenades back is rare. One thing that makes this easy is that it assumes you know exactly where the grenade is. This is unrealistic; grenades are small (SM-6 for typical fragmentation grenades) and combat is chaos.

If using Situational Awareness (GURPS Tactical Shooting p. 7) locating the grenade requires a roll. If you aren't using those rules it should still require a Vision roll (-4 if you are doing anything besides a Concentrate Maneuver to look for the grenade; a turn you really can't afford) the "in plain sight modifier" only applies if you see the grenade being thrown. The thrower can take a -2 to the attack roll to bounce the grenade in order to confuse tracking. This means you cannot claim the "in the plain sight" bonus and also have -2 to the roll to find it.

You might also require a Will-2 (or Will-based Soldier-2) roll to pick up the grenade, similar to Fire and Maneuver, Tactical Shooting p. 21. NPCs who fail don't attempt it, while PCs have a penalty to the attack roll equal to margin of failure if they try.