Structural Integrity Fields

So what are these structural integrity fields and why should I care? Structural Integrity Fields are a product of force field technology. They allow spacecraft to be constructed at a reduced cost and weight, while also permitting warcraft to be more survivable. A SIF is a system of planar force fields which are formed inside bulkheads and structural members to strengthen them. An SIF increases the amount of stress that such a bulkhead or structural member can take before it fails. As a side benefit SIF will prevent gravscanners and other force based technology from penetrating a hull which is reinforced with a Structural Integrity Field.
So how do I handle this in the game? An SIF allows a ship to be built as if it was built with a heavier frame, without the weight penalty. So in the GURPS VE2 or modular spacecraft system normally Hit points for a hull are calculated using the following formula:

area * 1.5 * Frame Value

Frame	Frame Value	SIF
Super Light	0.1	0.5
Extra Light	0.25	1
Light	0.5	2
Medium	1	4
Heavy	2	8
Extra Heavy	4	16

When a vessels has a Structural Integrity Field its Hit Points are calculated using the SIF multiple. It's cost is calculated as for the next highest Frame Value.
So for a vessel with a Super Light Frame the cost multiplier is normally 0.1. Outfitting the vessel with a Structural Integrity Field will raise the Hit Point multiplier to .5 while leaving the Mass Multiplier at .1, but the cost will increase to .25, still less then the 1 multiplier used for an equivalent light frame vessel. The technology's benefits are most dramatic at the heavy and extra heavy frame level used by Men 'O War.
Structural Integrity Fields do add a layer of cost and complexity to a vessel but the benefits are great enough that even small craft, such as brakes and HUVs often have them.