Originally deployed as a ship-mounted weapon meant for hunting large marine animals, the harpoon gun has been converted into a man-portable heavy weapon. It has a rugged look, made of bare steel and weathered wood, with a yellowish gas tank that contains the propellant and a trigger that is almost as big as the handle. Its harpoons are capable of inflicting very high damage (more than a Broadsider cannonball without maxed-out Demolition Expert), but it can only hold one harpoon at a time and takes a long time to reload.
Similarly to the railway rifle, projectiles fired by this weapon can pin enemy limbs to walls, as well as deal high limb damage.
Aside from the option of adding a sight or a low-powered scope, the harpoon gun can be modified to change its function on the battlefield. The flechette mod turns the weapon into a heavy shotgun of sorts by replacing its single large harpoon with seven smaller ones that get fired with surprisingly tight spread, thus making them effective at ranges where normal shotguns would not hit anything anymore. Flechette harpoons can inflict multiple critical hits per shot but severely reduce the weapon's effective range, and they still require a lengthy reload after every pull of the trigger. The barbed modification, on the other hand, is more straightforward and simply adds a bleeding effect to the single projectile fired.
The gun's standard and barbed harpoons can be recovered from targets and obstacles hit with them. Flechettes can only be recovered from dead enemies in the form of basic harpoons but may yield more projectiles than were originally fired.
- Admiral's Friend - Unique variant with the Instigating Legendary effect. It is sold by Allen Lee in Far Harbor.
- Defender's Harpoon Gun - Unique variant with the Penetrating Legendary effect. It can be obtained as a quest reward for completing Hull Breach 3.
- Skipper's Last Stand - Unique variant with the Resilient legendary effect. It can be obtained as a quest reward for completing Shipbreaker.
- Occasionally carried by Trappers.
- Can be bought from weapons vendors on the Island, primarily Allen Lee in Far Harbor.
- The harpoon gun's animations, properties, and general combat role are quite similar to the Broadsider's, with the difference of the latter having much shorter range and using a much less common ammo type. The only downside is the harpoon gun's lack of profit from the Demolition Expert perk which lets it fall behind a fully perk-supported Broadsider in terms of per-shot damage output.
- Changing the harpoon gun's ammo type from standard to barbed or flechette will result in a projectile speed drop (16000 units/sec or ~749.67 fps for standard). With flechettes flying at 25% (4000 units/sec or ~187 fps) of the speed of a normal harpoon and a barbed harpoon flying at 50% of the speed (8000 units/sec or ~374.02 fps) of a normal harpoon (the same as a railway spike from the railway rifle). These projectile speed changes can make the harpoon gun awkward to aim with at range, especially if one is used to a different type of round.
- When using the flechette mod for the harpoon gun, each shot will only take one harpoon while killed enemies can have as much as five harpoons in their inventory. This can be used to slowly accumulate harpoons, without needing the Scrounger perk.
Behind the scenes
|The following is based on Fallout 4 cut content.|
This weapon was to be released in the original game and was most likely tied with the quest 20 Leagues Under the Sea, but was cut. The model found hidden within the files of the original game and the completed weapon which appear in Far Harbor are dramatically different in appearance.
|End of information based on Fallout 4 cut content.|
Commonwealth mirelurks may sometimes fly off in random directions at high speeds after a successful hit with the harpoon gun, which may persist into the corpse if it is killed and render looting said corpse impossible.[verified]