I haven't tried, but I think that new throw value, throwRange, allows you to limit your thrown range to 0 or 1...
Oooh cool, didn't know about that.
I mean Item Transformations would definitely be a Suggestion but it has cool implications. Dioxine would probably go crazy with it. I didn't know if it was a thing yet.
Mainly my interest is fixing the TFTD problem of being able to throw crap underwater. Item Transformations would let you have grenades, but switch the item for a near-identical one that has throwRange 3 or somesuch (so you can still plant particle disturbance grenades).
I do have an idea about making a 1x2 Grenade Launcher punting gun (like ogre grenade launchers in Quake 1) and using simple ItemCategories to have grenades on land, and provide the punting gun for underwater with an arcing shot up to like Range 10-15.
In XC1 and XC2 the Grenades are the deadliest starting weapon and they stay effective all the way up until at least in-game May, and researching Alien Grenades is really easy. A good grenadier is deadlier than an HE Autocannon. So... by nerfing Grenades at least for tftd that can make the whole game quite abit harder (and close this silly loophole).
Edit - even with item categories to have a punting gun Item Transformations would allow transmuting Grenades into Ammunition to load into it, after the mission being over those items become the weapon again.
Though TBH that could be managed using manufacturing to "prepare grenade shells" with little cost or time involved, and the reverse of which too. Not really necessary for that point.