Russell's Salmon Alley House Rules.

Because I'm judgemental, that's why.

Salmon Alley is Alastair Beadle's excellent set of PBEM rules for simulating modern naval warfare.

Unfortunately, the demands of real life being what they are, it's difficult to keep a large scale Salmon Alley campaign going. I have decided to try to run one simple scenario at a time to keep the SA torch alive.

If you're interested in being on the Salmon Alley Talk mailing list, contact me and ask me to put you on the list.

The baseline rules for SA are at the official SA site mentioned above. Since the rules are not quite complete there, I will be making rulings which apply to any games which I run. These rulings may or may not be adopted in the official rules at a later time.

In addition to rulings, I'm also going to call attention to aspects of the standard rules which I think might benefit from changes. I invite comments on these items.

Rulings Index
Mid-Course Guidance
Nuclear Power Plant Minima
New Guns Table
Small Vessels Clarification
Surface Effect Vessels Clarification
Advanced RAS
Additional Aircraft Options
VTOL/STOL Aircraft
RAS Supply Ships
Compound Weapon Options
Carried Craft
Unpowered Weapons
Nuclear Warheads

Request For Comments Index
Internal Missile Launchers RFC
Carried Aircraft Fuel RFC
Aircraft Damage Rules RFC
Gun Rules RFC
Rules Still To Come

Mid-Course Guidance

In general, a platform which is datalinked or satellite linked to a friendly missile-armed platform can provide missile guidance to the missile-armed platform. A few conditions apply:

The spotter (guidance platform) and the bomber (missile launching platform) must be datalinked or satlinked together at the time of launch. After that, the datalink can be dropped provided that the missile has guidance at all times. Typically, the missile will either have inertial + active radar, inertial + IR, inertial + command, or command guidance alone in order to carry this out. Other combinations may be possible.

If the missile has inertial guidance, the spotter can tell the bomber what hex to fire at via datalink, and the missile needs no other guidance along the way to that hex (though it will usually need some other terminal guidance like IR or active radar homing) once it gets there.

If the missile has command-guidance, then either at launch time or at any point in inertially-guided flight, if the spotter has the missile within its radar range, the spotter can take guidance control of the missile. The spotter can even divert the missile from its original course if a juicier target is detected during flight (if the referee is up to that sort of detail). A chain of spotters, each data-linked to a neighbor, can hand-off a missile from one to another as much as they like, provided that the missile is always under command guidance. Thus a range-20 cruise missile could be guided by a string of helicopters to a target its full range away, even though the helos each only have a few hexes of radar range.

The hex target of an inertial guidance system can only be set at missile launch time, and can't be altered by mid-course commands. Once a command guidance system has taken control of the missile, inertial guidance is turned off and cannot be reinstated. More sophisticated programmable forms of inertial guidance will be introduced to the game later.

One tracking channel is required to guide a missile and a separate tracking channel is required to track a target. You can guide a missile with command guidance without having a target tracked, but if you only have one tracking channel you will have to hand off control to a platform with two channels in order to hit anything.

It shouldn't come up, but both the handing-off platform and the handing-to platform have to agree on the handoff for it to occur, otherwise the platform which last had guidance control retains guidance control.

Illumination guidance and laser-designator guidance do not require that the launching platform be the illuminating/designating and tracking platform, but they are not capable of hand-offs: the illuminating/designating platform must be illuminating the target from the moment of launch until the intercept. In the case of radar illumination, the target and the launcher must both be within the radar range of the illuminator and the angle difference to the target between the illuminator and the launcher must be 60 degrees (one hexside) or less. In the case of laser designation, the target and the launcher must both be within the same sector as the designator. Again, a data link is required in both cases -- illumination seeker incorrectly says "in radio communication".

Rationale and Commentary:

These rules were mostly implicit in the original rules; I've just made them explicit here, with new rulings regarding tracking channels and the semi-active systems. In Salmon Alley, an Aegis system could be represented by a shipborne radar with a large number of tracking channels, plus a datalink and satellite link. The missile ships (and submarines) of the former USSR relied on radar-equipped helicopters for mid-course guidance.

Nuclear Power Plant Minima

The minimum size of a nuclear power plant is 200 ship spaces. The minimum cost of a nuclear power plant is therefore 4000cr. This is 5% of a 4000-space hull. This does not include the size of the rest of the ship's engines, which as always require 10%-50% of the ship depending on speed. Under any strategic rule system, nuclear power plants will also require increased maintenance costs.

Rationale and Commentary:

There are real-world political and logistical reasons that small ships don't carry nucs.

New Guns Table

The guns table now includes damage values directly in the table rather than providing a shell size. Ammunition space requirements now exist. Ammunition costs cr4 per space. Ammunition may be either "on-gun", and take deck space in the same sector as the gun, or may be stored in the hull sector underneath the gun (i.e. if the gun is in the left forward deck sector, the ammo may be in the left forward hull sector or the left forward deck sector). The mechanism to load ammunition from either an on-deck or in-hull magazine is included in the mount space. Ammunition can be brought from other sectors in the same way that missile reloads are, if lifting gear is paid for. Note that damage and ammunition figures are per "burst", not per individual shell; the actual number of shells in the burst varies with caliber and isn't tracked in the game.

Each gun after the first in a multiple-barrel or multi-gun mount is purchased at half the space of the first, but at full cost. This yields slightly smaller multiple gun mounts than the original rule. A 6-barrel 30mm gun mount such as the Russian AK-630 therefore takes up 2 spaces for the first barrel plus an additional space for each additional barrel for a total of 7 spaces and 480cr.

Typical Caliber Range Mount Space Mount Cost Direct Damage Proximity Damage Bursts Per Space @ 4cr
12.7mm Point 0.25 40 13 N/A (4) 40
20mm Point 0.5 60 21 8 26
23-25mm Point 1 60 30 11 20
30mm Point 2 80 39 14 16
40mm Point 3 100 48 18 13
51-57mm Point 5 140 65 25 10
76mm Point 12 280 100 38 6
100-102mm 1 20 440 126 48 5
127-130mm 1 32 680 161 62 4
155mm 2 48 1000 196 75 3

Rationale and Commentary:

I had thought the guns table was broken worse than it actually turned out to be. Ranges were a bit too generous, and ammunition wasn't accounted for. One player wanted to know calibers for guns; I handwaved and said "make it up", but then got to thinking about the specifics.

I wound up surveying a lot of data on naval guns, putting the data into a spreadsheet, reverse-engineering relationships between bore size, shell weight, mount weight, rate of fire, and range, and then synthesizing some "typical guns" back from that.

One inescapable conclusion is that a "ship space" and an "aircraft space" are completely different in terms of mass. A ship space represents about ten times the mass of an aircraft space. This actually isn't unreasonable due to the structural requirements of ships versus planes -- when you add equipment weight to a ship, you generally add a lot of "dead weight" in the form of hull structure to support that equipment.

I selected a few sizes of guns close to the sizes in the original guns table to reconstruct via my spreadsheet; I N/A'd using proximity-fused shells in the tiny gun in accordance with the original rules. If additional sizes of guns are desired, let me know. These are typical modern guns; WWII cruiser and battleship guns are going to range from 100 to 400 spaces per gun.

Small Vessels Clarification

Small surface vessels (100 spaces or fewer) are entitled to use small (aircraft) ECM, small chaff, and small flare systems for self-protection.

A vessel of 100 spaces exactly can have "Fast" engines without being "surface effect". The original rule stated "smaller than size 100", but this allows simpler math.

Rationale and Commentary:

This ruling was sent in mail from Ali in February 1999, but apparently never incorporated into the online rules.

Surface Effect Vessels Clarification

Surface effect vessels get 1 deck space, free, per 3 hull spaces, not 1 per 5 hull spaces.

Rationale and Commentary:

This ruling was sent in mail from Ali in February 1999, but apparently never incorporated into the online rules.

Advanced Replenishment At Sea (RAS)

The basic rules require 40 deck spaces aboard the ship on the receiving end of replenishment regardless of that ship's size or supply requirements. This rule makes RAS equipment specification more complicated, but allows very small ships to accept resupply in a reasonable way.

Any number of deck spaces may be allocated to RAS acceptance gear. The cost is 2cr/space. However, the largest piece of equipment (i.e. biggest missile) which may be transferred in this way is equal to the size of the RAS gear. Transfer of ordnance, crew stores, and fuel takes from one-half to one hour per space of material transferred, divided by the size spent on RAS gear. Under good weather conditions and in daylight, the time factor will be one-half hour; in bad weather or at night, three quarters of an hour; in bad weather at night, one hour.

RAS equipment must be split into two sectors - one on the port side and one on the starboard side of the ships deck, as evenly distributed as possible, unless fewer than 20 deck spaces are used, in which case it all goes to one side sector.

For the Foundation Class frigate, for example, the default 40 spaces of RAS equipment are installed. This allows weapons up to 40 spaces to be transferred (which means the 30-space Standard SSMs can be loaded). Foundation carries 120 spaces of SSM, 40 spaces of SAM, 40 crew stores, and 140 fuel, for a total of 340 spaces worth of supplies. Therefore, she can be completely reloaded in 340 / 40 x 0.5, or 4.25 hours, under good conditions.

The lower value of the capacity of the supply ship and the capacity of the receiver is the gating factor during a transfer. A single supply ship can service multiple receivers simultaneously if it has sufficient RAS capacity, but in this case is limited to serving ships whose total size in hull spaces is less than or equal to half its own size. However, a supply ship of any size can always supply one ship at a time regardless of the single reciever's relative size. In other words, a 6000-space supply ship can simultaneously serve either 10x 300-space missile boats, 3x 1000-space frigates, 1x 3000-space destroyer, or 1x 10000-space aircraft carrier.

Rationale and Commentary:

The one-size fits all had to go to allow for very small ships to be replenished; to leave existing designs intact, however, the size could not be strictly dependent on the receiving ship's size, as this would invalidate existing designs which use the 40-space default. Limiting the transfer rate and maximum missile size according to space spent seemed like a good solution. To calibrate the limits, I just figured simple numbers that left the Foundation Class frigate both legal and sane. For very small ships with big missiles, another option is to pick the whole ship up with Launch/Recovery gear and load the missiles while it's in the hangar -- this is generally more costly for the tender, but cheaper for the carried craft.

Additional Aircraft Options

Afterburner Option: Add 5% of overall aircraft size to a conventional aircraft engine (not helicopter or rocket) at 5cr/space. The aircraft can expend extra fuel to move at the next higher rate (Slow flies as Medium, Medium flies as Fast, etc.), spending four hexes of fuel per hex traveled while doing so.

Efficient Cruise Option: Add 5% of overall aircraft size to a conventional or helicopter engine (not rocket) at 5cr/space. The aircraft can save fuel by flying at the next lower rate (Medium flies as Slow, Fast flies as Medium, etc.), spending one-half hex of fuel per hex traveled while doing so.

Non-Navalized Airframe: Reduce cost of complete airframe by 1cr/space (thus 4cr/space for hull and 2cr/space for wing/deck). Non-navalized aircraft require more landing runway and hangar space as per those rules.

Rough-Field Airframe: Increase cost of complete airframe by 1cr/space (thus 6cr/space for hull and 4cr/space for wing/deck). Rough-field aircraft can take off and land at "improvised" airstrips.

Skis: Skis allow takeoff and landing from deep and level snow, and require 5% of the aircraft size in wing/deck space, at cost of cr2 per ski space. A skiplane that doesn't need ordinary gear reduces airframe cost by cr1 per total aircraft space, but can only land on snow.

Seaplanes/Pontoons: Pontoons allow takeoff and landing from water, and require 10% of the aircraft size in wing/deck space, at a cost of cr2 per pontoon space. A seaplane plane that doesn't need ordinary landing gear reduces airframe cost by cr1 per total aircraft space, but can only land on water. A seaplane may be launched and recovered from a ship as if it were a carried surface vessel according to the carried craft rules.

Rationale and Commentary:

All of these options had been discussed to some extent in July 1999. The airframe/landing gear options were pretty much accepted by everyone. While my opinions on how the afterburner/efficient cruise options should work were clearly in the minority, I wanted to minimize the number of tables involved in aircraft design. The rate of fuel consumption under afterburner is a tough call, and I'm open to arguments for any value between 2x and 4x. Note that the existing SA rules (CIC, Aircraft Movement) suggest an afterburner consumption rate of 10x, with a two-step speed increase (without saying how an afterburner is acquired). Purchasing both efficient cruise and afterburner options gives a two-step speed range with an 8x fuel consumption range, close enough to the original 10x.

VTOL and STOL Aircraft

STOL: To build a STOL aircraft, add 5% of overall aircraft size to the engine. This cuts runway size needed for takeoffs and landings in half. Thus, an STOL/Fast engine takes up 50% of the overall aircraft size at 5cr/space, and the aircraft requires 15 times its size in runway (20x base, +50% for fast = 30x; -50% for STOL = 15x). Navalized STOL aircraft (all aircraft are Navalized by default) still require 8x for arrested landings.

VTOL: To build a VTOL aircraft, add 10% of overall aircraft size to the engine. This allows the aircraft to maneuver as if it were a helicopter (vertical takeoff, vertical landing, and hover) and to transition between conventional flight and vertical flight while in the air.

VTOL craft spend two hexes of fuel per vertical takeoff, vertical landing, or hovering turn (rather than 1 hex, as with helicopters). While executing these maneuvers, the VTOL aircraft is penalized by 3 agility points and is restricted to Medium or lower altitude.

Rocket STOL/Rocket VTOL: Pay the basic engine at 1cr/space, but pay the 10% or 20% surcharge at 5cr/space.

Rationale and Commentary:

Trying to build a Harrier-type aircraft with the original +20% figure for VTOL proved instructive; it wound up about 2 or 3 times as big as it should have been. +10% seems more tractable. VTOL craft might be Osprey-style tilt-rotor systems or Harrier/Forger/Freestyle-type ducted thrust jets. Same rules either way. The existing SA rules (CIC, Aircraft Movement) suggest a VTOL consumption rate of 5x, which seems like too much.

Replenishment at Sea (RAS) Supply Ships

Tenders, oilers, ammunition ships, and other "supply providers" may be built. For such support craft, buy the usual RAS acceptance equipment, plus holds for the supplies, plus elevators to move the supplies around. The amount of elevator you buy determines how fast supplies can be transferred: typically about one elevator load per one-half hour, though the recipient ship may need more time to stow weapons, etc. These elevators are purchased as aircraft elevators: 1 deck space plus 1 hull space and 1cr per elevator space. They cannot be used as aircraft elevators or landing pads.

Rationale and Commentary:

I don't know a lot about how this works in the real world. I ruled against using supply elevators as aircraft elevators on the grounds that there's rigging and cranes in the way.

Compound Weapon Options

This is not really a new rule, but making explicit certain options which are suggested by examples in the current rules.

A missile can carry missile launchers, torpedo launchers, or certain other equipment available to manned aircraft. Such a "bus stage" needs its own guidance, though inertial guidance is usually sufficient if the bus itself doesn't need to hit anything. The usual missile-on-missile concept involves a slow, long-range conventional engine bus stage with a fast, short-range rocket as the "intercept stage".

A torpedo can carry missile launchers, torpedo launchers, or most other equipment available to submarines. One use for this might be to allow a sub to launch antisurface missiles without giving away its position -- it can launch a torpedo to a point two hexes away, and the torpedo can then launch missiles.

Rationale and Commentary:

The former USSR developed an SSM (SS-X-N-27 'Alfa'?) that used the slow bus/fast intercept stage concept. Ali OK'd a design I was using which carried three short-range intercept missiles per bus, which made for lots of targets for the defender to deal with.

Carried Craft

To carry a surface or subsurface vessel aboard another surface or subsurface vessel - this can be landing craft, pocket subs, short-range attack craft, or anything else you can think of:

Vessel storage: Hull spaces equal to 150% of the size of the stored vessel, at 1cr per space. This is equivalent to, and sharable with, aircraft hangars (i.e. you can build a hangar and use it for aircraft on one mission and sea vessels on another mission, or mix and match), but does not include fuel for the carried craft.

Launch & recovery gear: the gear to get surface and subsurface ships into and out of the water is similar to a _double_ aircraft elevator for the carried vessel: 200% deck + 200% hull, at 1cr/hull space. This cannot be used as supply elevators, aircraft elevators, missile lifting gear, or aircraft parking space. One such set of gear can be used for any and all carried craft under the size limit.

Hovercraft launch & recovery gear: hovercraft can be launched with the same gear as surface or subsurface ships, or can use dedicated ramp-and-gate systems instead. Hovercraft ramp-and-gate systems cost 100% deck + 100% hull of the carried craft size, at 1cr/hull space.

Obviously, you can store 10 vessels and have launch & recovery gear for only one; this means it'll take you a long time to deploy your flotilla. Depending on weather, it takes approximately fifteen minutes to half an hour to deploy a single craft in this manner.

The carrier craft can provide supplies to the crews of the carried ships, but this must be accounted for -- they have to get fed even when their ships are in the hangar.

Rationale and Commentary:

Launching and recovering a vessel at sea seems pretty complex, hence the high cost of gear for it. Ships and transport planes will probably be able to discharge land vehicles for cheaper, when those rules become necessary.

Unpowered Weapons: Bombs and Depth Charges

Weapons without engines (depth charges and iron bombs) will take a further -10% penalty to hit beyond any other applicable factors. It's usually worth it to buy a minimal rocket engine (10%, minimum 0.1) or ship engine (10%, no minimum) to avoid this penalty.

Seekers are allowed on unpowered weapons.

For now, no naval mines.

Rationale and Commentary:

I dithered back and forth between a -10% and -20% to hit. I settled on -10% because real world air forces do rely heavily on iron bombs and guided unpowered bombs, and I wanted them to be usable in SA. I still wouldn't bother with them unless I was trying to reconstruct a particular historical scenario.

Nuclear Warheads

Nuclear warheads cost 100 times the cost of conventional warheads: 500cr per warhead space. Minimum nuclear warhead size is 5 spaces. A nuclear warhead may be set at launch time to detonate as airburst or groundburst. In the case of a groundburst, the weapon may attack a particular target as usual; if it misses the target, it still "hits the sector" (this requires inertial guidance if it's going to hit a sector in a different hex than it's launched from). In the case of airburst, there is no direct hit, but damage to other targets is increased.

In all cases, damage is applied evenly to all target vessel sectors. Consult the following table to determine how much damage is done at a given range from the blast. Aircraft take double damage from nukes. For simplicity, missile or shell velocity is not considered in nuclear warhead damage.

Detonation Mode Direct Hit Same Sector (0-5 nm) Same Hex (5-15 nm)
Groundburst 500 damage per warhead space 25 damage per warhead space no damage
Airburst N/A 50 damage per warhead space 5 damage per warhead space

Nuclear warheads are never available unless so specified by the scenario or the referee. The referee has the last word on nuke availability. There will usually be fallout of both the radioactive and political sort as a result of their use. Additional damage from radiation isn't covered, but should be. Referee may feel free to improvise. Nuclear warhead yield in real-world terms is roughly 20 kilotons per warhead space.

Rationale and Commentary:

The minimum warhead here can be carried on the Standard SSM, which seems to be about the same size as BGM-109 Tomahawk or AS-15 Kent. Direct hit damage is increased by a factor of 10 at most, but warhead cost is increased by a factor of 100; that seems reasonable. The minimum warhead will do 2500 damage on a direct hit, which will basically vaporize frigates and destroyers and mission-kill anything larger. In airburst mode, you can get the equivalent of a direct hit with a same-size conventional warhead on everything in a sector at once.

Internal Missile Launchers - Request For Comments

The existing rules on internal missile launchers state:

"Missile launchers cost 5cr for each space they take up (excluding the extra 20% space for hull/fuselage mounted launchers)".

However, Example 2 in the same section indicates that the 20% is charged at 5cr/space. I think the deck space should be charged (i.e. internal launchers should be more expensive than external ones), but I'm reluctant to directly contradict the rule as written. Any other opinions?

Carried Aircraft Fuel - Request For Comments

The existing rules indicate that aircraft carriers can refuel their aircraft as many times as they want up to the supply duration of the carrier. I understand the wish to avoid bookkeeping, but this handwave bothers me. Any other opinions?

Aircraft Damage Rules - Request For Comments

Typical air-to-air missiles in the 2-8 space range are going to deliver about 20-50 points of damage with proximity warheads. This seems like it's not going to be enough to take down light military aircraft in the 100-200 space range. On the other hand, you're still liable to get a mission kill (particularly if proximity damage is divided up to hit multiple components, which is a change I've considered for ship targets).

One factor involved is that a real world flying aircraft is liable to become drastically less aerodynamic when a missile hits it, and this change is going to cause as much damage to the plane as the missile itself! Perhaps any damaged component should continue to take additional damage every turn that the plane flies above Slow speed?

Another option might be a rule that any (each?) fuel hit on an aircraft will cause it to leak one space of fuel per minute thereafter.

Rules Still To Come - Request For Comments

The following are items that Ali and various players wanted rules for. Let me know if there are other ideas you have, or implementation suggestions for these rules.

• Nuclear warheads.
• Antiradar seekers, home-on-jam seekers, deceptive transponders (blip enhancers).
• Improved agility options for aircraft.
• Advanced guidance systems, remotely piloted vehicles, and robot vehicles.
• MAD and FLIR sensors, terrain-following radars, and other goodies.
• Armor and tweaks to damage rules (distributing damage from proximity warheads).
• Alternative warhead types: deep-penetration, fuel-air explosive, cluster bomb, etc.
• Ground vehicle design rules.
• More strategic-level rules.

Author: Russell Bornschlegel, Last revision: 2001/9/25.

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