I've been playing around with designing attachments for ships using tractor beams, and this particular design has just saved my salvage ship from certain doom so I thought I would share it.
It is intended to be attached via tractor to other ships, with them supplying the engine power. I've used a few here and there on military ships and have occasionally been attaching them to commercial ships that are going into areas that may be unsafe. I use either big military jump tenders or gates in those areas so it doesn't hold back the commercial ship from jumping.
Auxiliary class Point Defense Module 3,000 tons 200 Crew 574.2 BP TCS 60 TH 0 EM 0
1 km/s Armour 1-18 Shields 0-0 Sensors 1/1/0/0 Damage Control Rating 2 PPV 4
Maint Life 7.35 Years MSP 263 AFR 32% IFR 0.5% 1YR 9 5YR 128 Max Repair 100 MSP
Magazine 688 Tractor Beam
AM Missile Launcher (4) Missile Size 1 Rate of Fire 5
Missile Fire Control FC20-R1 (2) Range 20.7m km Resolution 1
Mosquito IV AM Missile (688) Speed: 80,000 km/s End: 0.7m Range: 3.4m km WH: 1 Size: 1 TH: 1626 / 976 / 488
Active Search Sensor MR20-R1 (1) GPS 87 Range 20.7m km Resolution 1
Missile to hit chances are vs targets moving at 3000 km/s, 5000 km/s and 10,000 km/s
This design is classed as a Military Vessel for maintenance purposes
I had sent my salvage ship into a system that I thought was clear to pick up some wrecks. Exploration vessels had been through and surveyed the entire system (geo and grav) without trouble, so I assumed it was safe but still left the module on it just in case. A few days into salvaging one of the wrecks the ship picked up a thermal signature on approach. I activated the active sensors and told the ship to fly to the nearest JP while I dispatched some military vessels a few systems away to head there, but they would be too late to defend the salvager. The enemy vessel shot 191 size 6 missiles at my salvager, went away, then came back with another load and fired 191 more at the salvager before it made it through the jump. The little missile pack shot down all of them and got the salvager out safe at the cost of 382 AMMs. Expensive, but cheaper than a new 60k ton salvage ship. My military fleet then arrived and dealt with the enemy, and the salvager went back in and finished the job.