System: Full Thrust
Publisher: Ground Zero Games
by David Manley
Chief Officer Fergus Kehoe watched his control console with satisfaction. His ship, the tanker Confederation Naval Auxiliary (CNA) Fort Brockhurst had been alongside the carrier for several minutes now; the transfer lines had been rigged and fuel was flowing from the tanker to the warship. Another few minutes and the job would be complete. The Captain would be happy with a routine transfer completed well to time.
The ship's Main Broadcast crackled into life. 'Unknown contact on intercept course! Probable Hostile. Prepare for Emergency Breakaway!". Kehoe's hands leapt to the transfer pump controls. In seconds the Captain would order evasive manoeuvres - already he could feel the throb of the main engines powering up - Kehoe had to shut down the pump before breakaway or risk losing fuel or worse, risk damaging the pumps. Suddenly the routine transfer wasn't so routine...
As a (still active) naval wargamer I was always happy with Full Thrust's naval feel. However, something was missing. Some of my most exiting naval wargames revolved around the auxiliaries which travelled with the fleets, and in campaign games the opposition's tankers were always a prime target. With this in mind I set about incorporating these forgotten ships into Full Thrust.
Fuel and Drives
I have assumed that ships in Full Thrust use hydrogen fuel to power their reactors. This is a fairly common commodity in the Galaxy - it can be skimmed from gas giants or produced from water drawn from a world's oceans or icecaps. This assumes the ability to enter a planetary atmosphere, and whilst some ships are atmosphere-capable (see More Thrust), most are not. More of this later.
Under the Full Thrust design system 50% of a warship's mass is taken up with drives, fuel, accommodation etc. I have assumed that 20% of the mass is fuel, 5% is stores and the remaining 25% is hull structure not associated with systems, drives etc. this compares well with modern 'wet' ships, but feel free to modify these values if you wish. Ship drive systems are assumed to take up a similar proportion of the ship regardless of power output;drives vary in efficiency (again not too far removed from current ship practice). A standard drive can 'jump' the ship 10 Light Years (LY) with costs as in the Full Thrust design rules. Drives can jump a ship up to 20 LY - the cost of the drive is the basic cost of the drive times maximum range, divided by 10 (e.g. a 10 LY drive costs 1.0 times the basic cost, a 14 LY drive costs 1.4 etc.). I have chosen 10 LY as the standard range rather than 6LY as suggested in the Full Thrust campaign rules as it simplifies the maths, but feel free to change this to a 6 LY standard if you wish.
As stated above a standard ship hull is 20% fuel. This is enough for one maximum range jump, plus enough to power the ship's electrical systems, Normal Space Drive, screens etc. for one year (thus removing them from consideration). Designers may allocate additional mass to fuel tankage to create ships with extended range or to act as tankers. To assist in book keeping, one Mass point equals 10 Fuel Points (FP). From this, the ship uses (0.2 x Mass) FPs per Light Year of travel.
To carry out a refuelling operation the tanker and the recipient must be travelling at the same speed on the same course and be within 1". Once this is achieved it takes one turn to pass fuel lines and set the pumps to work. Fuel transfer depends on the number of pumps available. Each pump can transfer 20 FPs of fuel per turn (for design purposes pumps use 1 Mass and cost 10 points). Once refuelling is complete one turn is needed to shut down the pumps and disconnect the transfer pipes. Auxiliaries can refuel up to 4 ships simultaneously, but each ship must have at least one pump allocated to it.
In an emergency the tanker or recipient can initiate an Emergency Breakaway. In this case the full shut down procedures are not used and each ship can manoeuvre independently. There is a risk of fuel loss or damage; roll ad6 for each pump in use. On a score of 1-4 there is no damage, but on a5 or 6 roll again. On a 1 or 2 the auxiliary loses 1d6 FPs, on a 3 or 4the recipient loses 1d6 FPs, on a 5 both ships lose 1d6 FPs, and on a 6both lose 1d6 FPs and the fuel pump is damaged.
Ships engaged in refuelling operations are more vulnerable to attack - screens must not be in use, and all hull box damage is doubled to simulate the effects of fuel filling trunks being in use, cargo shipping routes being opened up etc. This makes the Emergency Breakaway a particularly useful manoeuvre!
Streamlined ships can skim fuel from gas giants or from oceans. Most fleets carry fuel shuttles which can skim fuel for their parent ships. To skim fuel the ship or shuttle must enter the planet's atmosphere (gas giant), land on the ice cap or enter the ocean (see More Thrust). Tank filling takes one turn from a gas giant's atmosphere, two turns from an ocean or five turns from an ice cap. Before it can be used the slush fuel must be refined, a process which takes 5 turns to complete - 20% of the slush becomes usable fuel per turn. All warships are assumed to have fuel refineries as part of their standard fuel system. Civilian ships may have them fitted at accost of 10 points (there is no Mass cost). Fuel shuttles are not generally fitted with refineries.
By this I mean food, ammunition etc. To simplify the system I have assumed that any solid transfers take place at the same time as fuel transfers. In any case, food waste is likely to be largely recycled by the 22nd Century and ammunition ceases to be a consideration when most weapons are energy-based. Lumping solids in with the fuel does not detract form the system and would only bog things down, but if you want to develop such a system, feel free. Bear mind, however, that auxiliaries in the Full Thrust era are likely to be 'one-stop' replenishment vessels, carrying stores and fuel together, similar to today's AORs of the Royal Navy.
The possibilities for scenarios based on auxiliaries is endless. Examples include the hunt for a commerce raider's supply tanker along the lines of the German tanker Altmark in WW2 or attempts to get fuel to a valuable ship in a fuel-less system (5th Frontier War players will sympathise with a friend of mine who, when playing the game ordered a large and valuable fleet to jump into a system with no gas giant , no planetary oceans or icecaps and no fuel facilities whatsoever - scratch one fleet!). Warships can get in on the act as well - commerce raiders are likely to carry fuel shuttles if they are not streamlined, and a scenario could be based on the efforts of such a raider to refuel from a hostile world whilst being pursued. Finally, campaigns become much more exiting when your opponent has valuable supply ships to attack, but never forget that you have those of your own to protect.
Remember that none of this is cast in stone. If you want your ships to have enough fuel to make two, four or however many maximum range jumps on a full tank of fuel, so be it. If you want your standard starship travel distance to be 6 Light Years or 10 parsecs, that's OK. However you decide to arrange things, bringing auxiliaries into Full Thrust adds an exiting new dimension.
Ship Design Examples
1. The Heavy Cruiser on page 14 of Full Thrust has a mass of 32. Of this, 20% is fuel. This is 6.4 Mass, or 64 FPs. It has a standard 10 LY drive, so it could make one 10 LY jump, two 5 LY jumps etc. Fuel usage is 6.4 FP/LY
2. A fuel tanker is based on the Bulk tanker on page 15 of Full Thrust. It has a mass of 100, so 20 Mass is devoted to fuel, giving it 200 FPs. 40 Mass points are available for cargo (50 - 10 for the defensive weapon systems). Four pumps are fitted, leaving 36 Mass for extra fuel tankage, adding 360 FPs. It can transfer up to 80 FPs per turn.
3. A Fuel shuttle is built based on the Mass 5 dropship in More Thrust. Allowing for the shuttle's own fuel, structure and drives, it can carry 2.5 Mass of slush fuel, or 25 Fps.
4. The courier on page 14 of Full Thrust uses 0.2 Mass for fuel, or 2FP. The basic version has a 10 LY drive costing 2 points. A long range version is built with a 16 LY drive; the drive costs 1.6 times the normal drive costs, or 3.2, which may be rounded to 3. Finally, an extended range version is built. This sacrifices the 'C' battery for extra fuel. 1 Mass is devoted to extra fuel, giving 10 extra FP. This allows the ship to perform up to 6 maximum range jumps before refuelling.
Ed Note: Full Thrust is a simple, flexible and highly popular game of starship combat which must rate as one of the all time Classic games. Full Thrust has won the Best SF Rules category every time the SFSFW Awards have been held. For further details regarding price and availability, send an SSAE to Ground Zero Games PO Box 337, Needham Market, Suffolk, IPA 8LN.
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