As things have started moving again in our starfire campaign and the Alien mung has intruded upon my space (or Squidzie space or both) the question of gunboats and the local minefield has been forced under my nose. I had a look at the rules and it is clear that the UTM uses the rules from ISW4 verbatum for this particular section. And well based on the way the rules are written my feeling is that they were written by David Webber and that the SDS didn't change them when they took over the process.
I am not familier with the rules pre 3rdR except in a rather vague general way (I played games under other rules sets but never saw the rules) and so I have to guess a bit. I do know that mines had an attack roll of 7. I also know that point defence operated by 9-7-5-3-1 process leading to minesweepers being designed so that as many mines as possible would be intercepted with a 9, hence in Crusade you see sweepers with huge numbers of Dx something which in 3rdR actually makes no sense 5 Dx would be acceptable and 10 Dx would be the most needed for a BB sized sweeper. Point defence versus mines can't use targeting (extra shots applied to increase the number of the intercept) in 3rdR so there is no need to jam a mine sweeper with point defence.
Anyway using what I know, and the rules for gunboats the mine field vrs GB rules seem to make sense. A GB squadron is attacked by 10 mines. A GB is -3 vrs ship to hits, 7-3 = 4. Thus of the 10 mines attacking only 4 hit. The rules say roll 4 dice. Makes sense.
Then the GB has a Dxz so it has a 9 to intercept. Chance of a kill is 1 in 10. Makes sense the rules say the kill number is a 1. A +1 for AAM (which has penaids for -1 PD number) and +1 for turn of transit (where PD is at -1) also make sense.
So it looks to me like the rules are from 3rd or earlier version.
In 3rdR though the rules are different Dx is 5 on 7 not 9-7-5-3-1 and able to restart. Non-minesweepers get a -2, no targeting bonus applies either (this rules is forgotten by most) so the 7 (or 6) stands.
So starting with the same 4 mines inbound you now have a base intercept chance of 7, or 6 is you apply the -1 to all PD rolls. Unless the GB know the mines are present they also should get a further -2 on the intercept number, plus the other ones listed before.
But the baffle gab rules for 3rdR say there is really 70 mines in the pattern not 50...so 14 mines would fire on the gunboat squadron not 10 and in this case 14*.4= 5.6 which could be rounded up to either 6 (mathematically) or down to 5 (game play) but basically you should roll more dice per squadron.
The 3rdR PD rules push the kill number high: Base 3 + 1 (turn of transit) +2 (non-minesweeper) = 6 to kill and 7 to kill vrs AMMF (+1 if using all PD degraded by 1). This will seriously degrade GB moving through a minefield at speed on the turn of transit or any other turn as you have to know the MF is there to get the minesweeper status. This leaves them with slow 1 hex a turn advances. That probably gets the GB slaughtered by firepower.
The only saving grace for the GB is that a pattern can engage only a single squadron so send 30 squardons through a minefield with 10 patterns and only 18 will be engaged (10 on entering and 8 on leaving). Still with a wide enough minefield even with lower patterns per hex the GBs are going to be seriously attritted.
I may be wrong in how the rules were arrived at, but on the other hand the difference between a GB and an EX class ship is minimal and EX class ships would be obliterated entering a minefield so that GBs take a beating is not really unrealistic. Fundamentally the changes to the point defence rules in 3rdR made minefields considerably more dangerous to ships as a whole. Crusade minesweeps could deal with very heavy patterns of minefields but 3rdR minesweepers max out at a 7 rather than the mines being able to be intercepted at a 9 base. A 3rdR ship in a AAMF will suffer seriously as the best you get is a 6. A BB sized ship will thus suffer per AMMF pattern 25*0.4*2 = 20 points of damage per pattern on average. Still 6 BB sweepers would require 40+ AMMF patterns to likely destroy them, and there is all the other things (EM, and EDM drones) plus beam weapons to add to their survivability.
What are other peoples thoughts here? Change stuff? Not change stuff? Am I barking up the wrong tree?
Added in Edit: -2 for non mine sweeper and a bit of grammar improvement to enhance readability.
