Are there rules for attaching weapons to mounts or characters?

Question

Let's say Bobby has a shield in his left hand and a whip in his right hand. Bobby also has a couple of nets, and is mounted on his favorite pony.

It's Bobby's turn, and he sees an enemy within reach of his nets. He drops his whip [no action] to grab a net [free object interaction] before throwing it.

But Bobby is concerned: he doesn't want to lose his precious whip because he dropped it on the ground far away, so he would like to have his weapon somehow roped to either himself or his pony so that it will stay dangling close to him when he needs it again.

Can Bobby do that (attach a weapon to himself/his mount)? Would there be drawbacks (attack disadvantage/penalty with the weapon due to its attached status; attack disadvantage/penalty for the other weapon due to the attached one being in the way; possibility for the dangling weapon to hurt him and/or the mount; etc.)?

Answer 1

Short Answer: Yes

It was an equipment item in previous editions of D&D, that somehow didn't make it into the current edition. Here is the text from 3.5:

This red silken cord is strong and springy. With a tug, the connected longsword flies into your hand.

A weapon cord chains your weapon to your wrist, so if you drop it (or are disarmed) you merely need to tug on the weapon to bring it back to your hands. You can pick up a dropped weapon connected by a weapon cord as a swift action.

The cord is a little cumbersome, on account of having a weapon dangling from the end of it. When attacking with other weapons while a weapon hangs by the cord you take a -1 penalty for light weapons, -2 for one-handed weapons, and -4 for two-handed weapons. Other items can be attached (such as wands) as a weapon of equivalent size. Attaching or removing a weapon cord is a standard action.

If you have Two-Weapon Fighting you can pull but both weapons as part of the same swift action.

The weapon cord has 0 hardness and 10 hp.

Market Price: 300 gp
Weight: — lb.

This information could easily be converted, but there is no official mention in 5e sources. The penalties here could be left intact, or a general disadvantage can be applied.

If you're looking for the official source, it can be found in the equipment section of the 3e and 3.5e PHB. There, it's an attachment to your armor or gauntlets.

To answer your question at the end, a weapon on a cord or chain probably won't do too much damage to a mount or the character itself. A good example of this was a medieval technique for swords called half-swording, where the soldier would grab the blade of their own sword with their gloved hands in order to more precisely pierce the opponent through armor gaps.

Most weapons rely on the force of a swing or thrust to be able to deal any damage. Also, even with simple leather or cloth, any kind of armor will be able to protect against the hanging weapon. Therefore it shouldn't be a rule that a weapon swinging from a cord be able to do any real damage to anyone

Answer 2

No, there are no rules for 5e that cover this situation.

As you stated, the Rules in the PHB on page 190 for interacting with an object let you pick one up at no cost (pending no other interactions during your turn) are sufficient for characters on the ground, mounted characters still have a problem with reaching their item.

Caveat Emptor on a homebrew solution

Part of the current ruleset also allows you to pick up someone else's item that is on the ground. The Disarming Maneuver from the fighter would be rendered useless should a weapon cord be made available.

However, should you want to introduce the weapon cord, there is an excellent suggestion for homebrewing in AS.Beauliu's answer.

Answer 3

You can do it, despite the fact that there is no specific rule in 5e

Can Bobby do that (attach a weapon to himself/his mount)?

Of course he can, unless the DM says otherwise. And if they do, they should explain why (not just "No you can't do it because there is no rule for this"). In 5e characters are supposed to do things that aren't described in the PH, since the book is just too small and doesn't cover all possible situations. It is the DM's job — to make rulings, using various game mechanics as a tool.

This won't help you to save your action though

However, attaching a rope to your weapon doesn't help you to change weapons faster.

He drops his whip [no action] to grab a net [free object interaction] before throwing it.

Nothing in the rules says dropping your weapon is "no action". On the contrary, the PH explicitly says you have to use your action when you are interacting with two different objects.

See PH page 190:

You can also interact with one object or feature of the environment for free, during either your move or your action.

If you want to interact with a second object, you need to use your action.

He drops his whip and grabs the net — that's all he is able to do this round. He will have time to make an attack in the next round.

He could also put the whip back on his belt instead of just dropping it. It uses the same time — a bit unrealistic, I agree, but more realistic than having your weapons dangling on cords behind your mount and being able to switch them instantly because of that.