Skip bombing may be a bit more involved than that (or at least some different efefcts may need to be considered). Here's a description:
"Many hours of practice taught them that approaching the ship from 2,000 ft., then dropping down to an altitude of 200 to 250 ft. (maintaining the air speed of 200 to 250 m.p.h.) and releasing the bomb --equipped with a 4 to 5 second delay fuze-- 60 to 100 ft. away from the target was the way to do it. Thanks to the efforts of these men, the percentage of targets hit increased from less than 1% to 72%."
"Skip bombing is a low-altitude bombing attack that has been successfully used against naval targets. It consists of a string of from two to four bombs dropped from such an altitude and distance from the target that a complete miss is improbable. Unless the target is of such importance that heavy losses can be accepted this method of bombing should be attempted with large heavy aircraft only at night and under most favorable weather conditions. The attack should be delivered with the idea in mind of securing a maximum of surprise and should not be repeated against the same targets too often. Skip bombing attacks should be made with the target outlined against light of either flares or the moon, and in such a location that the pilot is able to accurately tie in his altitude with a visible beach or other well defined objects. The altitude of the attack should be from 200 to 300 feet and the bomb-release line from 350 to 200 feet from the target."
"Skip bombing with heavy bombardment aircraft must be considered an attack of opportunity. Any attempt to skip bomb a war vessel in the light, unsupported, would probably be particularly hazardous because of lack of speed and manoeuvrability and small amount of forward fire power. Successful daylight attacks have been made on unescorted merchant vessels by heavy bombers, and light bombers heavily armed forward with .50 cal machine guns have been highly successful against war vessels. This success of light bombers was due to surprise, coordination, and heavy forward fire, none of which are likely to exist in a daylight attack on warships by heavy bombardment. Repeated skip bombing attacks in the same area would result in some form of protection designed to defeat it. It is, however, when the opportunity presents itself, an ideal surefire method of hitting the target."
Suggest as follows:
1) bombing aircraft makes a torpedo attack, but uses bomb AD&DD
2) attack range is 2" not 4"
2) apply +2 DRM to the attack
3) give AAA a +2 DRM to its attack on the aircraft and do not allow aircraft to dodge.
4) use torpedo critical hit rule