With the implimentation of jetpacks to get you to the surface of a ship, tractor beams to slow it down, and grav boots to allow you to walk across the surface of a ship, I\'m surprised no-one has mentioned breaching charges / breaching plasma.
The concept of the breaching charge is fairly simple: A powerful, slow-to-detonate device that pierces shields but detonates in an extremely controlled manner. You would place it on the top of a ship going under a certain speed, and the size of the detonation would depend on the amount of \"powder\" in the charge. The amount of \"powder\" would also dictate the time it takes to detonate. The detonation would occur in a 3*3*X box, with the X being the vertical distance (both up and down) of the explosion. It would pierce shields, and create a perfect hole for a boarding team to enter. However, the long priming time would allow for the crew of the ship to react, and turrets could destroy the block. However, it would be an extremely strong block, to cope for the long priming time. It would also require fair amounts of planning ahead: You could have a massive breaching charge able of 100 blocks of piercing, but if you don\'t pierce in the right spot it won\'t matter at all.
Then, there\'s Breaching Plasma. It\'s much weaker in health, and still pierces in 3x3. However, it is constantly drilling through hull: doing constant damage to all the blocks beneath it, ignoring shields, and once it\'s done with a layer of blocks it moves down a layer. This would be useful for the extremes of boarding: a single, extremely planned shock team hitting a thin layer of hull, or mass amounts of boarding crews trying to overwhelm the ship\'s boarding countermeasures. Also, the more power in a Breaching Plasma, the faster it burns through. There would be a max burn speed, however, contrary to the Charge\'s unlimited pierce. However, there would be disadvantages. For one, the health of Breaching Plasma would be 25%-35% less than a Charge. Plasma would also have to be manned, so one person in the breaching crew would have to stay on it in order to continue drilling through the hull. However, its speed is good for shock troops, and it\'s more useful on planets, since it drills not just vertically but horizontally, depending on how it is placed.