Lost in minefields
Exploring the unknown but valuable depths of minefields. (v 1.3)

By Timo Kreike

Introduction
Most of the experienced players know what torpedo type to use to lay minefields, and what torpedo type is most efficient in minerals or MC to bring down shields. However almost nobody knows that minescooping can be a very valuable effort!

Minescooping can save you up to 64 % of the price of a torpedo, and it could save you hundreds of megacredits a turn. On the other hand if you don't do it right it could cost you thousands of MC a turn!
Lost in minefields? Here's your way out!

The Minelaying Formula
The formula used by the host program to calculate the number of mines that can be made from a torpedo is:

Since all minelaying and minesweeping formulas are based on the position of the torpedo and not on the tech level, this position is used throughout the article.
The following article is based on Tim Wisseman's original shiplist and original torpedo statistics. Look at the table below for the torpedo names, tech levels and positions of the original shiplist:

The cheapest mine unit
First some familiar stuff to start with. Eden Tans excellent InfoList (1) gives us the following table for the prices of mine units (2):

This enables us to derive a fast conclusion: the cheapest mines in megacredits are made from Mark 4 Photons (tech 5, position 6), and the cheapest mine units in minerals are made from Mark 8 Photon torpedoes (tech 10, position 10).

To answer this question, we'll have to combine the mineral cost and the cost in MC. This can be done when we look at the Alchemy ships in VGAP. The regular conversion of supplies into mineral says that 3 kT supplies equals 1 kT of minerals.

To build 1 torpedo you need 3 kT minerals: 1 kT of Molybdenum, 1 kT of Tritanium and 1 kT of Duranium. This amount equals 9 supplies, or 9 megacredits. So we multiply the column labelled 'Min/torp' in the table above by 9 and add this to the column labelled 'MC/torp'. This results in the following table of the overall cost of a mine unit:

Conclusion: when you take all resources into account the cheapest torpedo for laying mines is the Mark 7 Photon torpedo (tech 8, position 9), immediately followed by the Mark 4 Photon and the Mark 8 Photon.
The close difference in total cost between the Mark 7 Photon and the Mark 4 Photon enables you to switch to the Mark 4 Photon without spending too much. You can use the Mark 4 Photon when you've got enough minerals, the Mark 4 Photon costing 0.278/0.123 = 2.3 times more minerals than the Mark 7 Photon. The same conclusion applies when considering the Robotic minelaying advantage (3).

Cheaper torpedoes
We can use this principle of 'different priced mine units' to get cheaper torpedoes. How? The answer is simple: Lay a minefield of cheap mine units, and scoop the minefield up as higher priced mine units! It should be clear that this method only works for registered players due to the registered 'msc' friendly code you need for mine scooping.

To start with you'll have to be very careful how many torpedo of a certain type you use for the minefield. For example 10 position 6 torpedoes would form 10 * 6* 6 = 360 mine units - if you would scoop them up as position 5 torpedoes you would end up with 14 position 5 torpedoes and a minefield of 10 mine units you can't scoop because they can't be put together to form a complete torpedo.

Those remaining mine units are a loss - they will deteriorate by a percentage per turn set in the host configs. This is however a loss that can easily be prevented: you can get the max out of the torpedo conversion by using the exact number of torps of type A that matches the position of torpedo type B. Using the same example as above: to convert position 6 torpedoes to position 5 torpedoes you'll have to start with 5 * 5 = 25 position 6 torpedoes. These fill form 6 * 6 = 36 position 5 torps. In general: use A * A position X torps to convert them to X * X position A torpedoes. Use the following table to determine the perfect torpedo conversion rate. (4)

TABLE 4:
Perfect Torpedo Conversion Rate

Use multitudes of the above ratios to prevent unnecessary losses.

If you subtract these values, i.e. when it says A -> B you calculate B - A, you get the number of extra torps that is generated by scooping up the minefield. This number equals an amount of 3*(B-A) kT minerals, or 9*(B-A) megacredits. A positive number (labelled green) means that the torpedo conversion generated minerals, a negative number signals a loss. The following table shows these numbers in megacredits.

This table shows you what conversion will cost you minerals, and what conversion will gain you minerals. For example when you turn 4 position 5 torps (Mark 3 Photons) into 1 position 10 torp (Mark 8 Photons) you'll lose 27 MC (or 9 kT) worth of minerals. The general suggestion of this table seems to be that with respect to the minerals only conversions from high tech torps to low tech torps are profitable.

We're not through yet - this table only covers the mineral costs of the conversion. Next topic: the cheaper torpedoes promised in the beginning of the article. The method to calculate this was already briefly described: "Lay a minefield of cheap mine units, and scoop the minefield up as higher priced mine units!"

So we'll have to look at the prices of mine units in the column labelled 'MC/torp' in the second table of this article and search for good combinations. To get a good indication of the usefulness of a combination, the ratios of the prices of the swept and laid torpedoes is calculated:

If the resulting value is lower than 1 (labelled green), the scooped torpedo is cheaper in MC than the same topedo built at a starbase. A value of 0.500 means that the scooped torpedo has half the price as the built torpedo. The torpedo price conversion factors of all possible combinations are listed in the table below.

This shows you that when you lay position 6 torps and scoop them up in position 1, you'll get those for only 36% of the regular price in MC! Too bad those position 1 torps themselves are pretty useless. But look in the last column: what about tech 10 torps for 67% of the regular price? Just lay a couple of position 6 torps (tech 5, Mark 4 Photon) and it happens right where you're standing!

This last table (Table 6) only shows the price in MC per mine unit laid/scooped. The next two steps will adjust these values to match numbers used for the prefect torpedo conversion rate (Table 4) and include the minerals gained through the conversion (Table 5).

The following table shows the number of megacredits gained through the conversion of torpedoes. This is calculated by simply extracting the number on megacredits actually spend on the laid torpedoes from the number of megacredits you would have spend to build the number of torpedoes you scooped. A positive value (green) means the torpedo conversion saves MegaCredits.

Interesting results... Unlike table 5 which seemed to suggest that only conversions of high tech torpedoes to low tech torpedoes are profitable, the results in this table are quite spreaded, and therefore promising for surprising results!

And now the final blow: combine table 5 and table 7 to show the total resources gained and lost through perfect torpedo conversion:

All positive values (green) indicate a combination of torpedo types that actually make money for you! Some good combinations can be found:

25 position 6 (Mark 4 Photons) scooped up at position 10 (Mark 8 Photon) is very usable, and it saves you a bit (Don't get excited: it's just 17 megacredits). 100 position 9 torps (Mark 7 Photons) scooped up at position 10 (Mark 8 Photon) save you 603 MC! On the other hand if you take the wrong combination and you convert Mark 5 Photons (position 7) into Mark 7 Photon (position 9) torpedoes it can cost you thousands of MC worth of resources a turn!

The position 6 torpedo (Mark 4 Photon) is in general the best idea to start laying mines with and scooping them up again as other tech levels.

Take for example the Lady Royale Class Cruiser. When two of those are filled with 160 clans they generate 320 MC each turn. A more interesting option would be to use this second combination as described above and fill one Lady Royale with 100 Mark 7 Photons and 60 clans, its mission set to Lay Mines. Fill the second Lady Royale with 79 clans and its Mark 8 tubes set to sweep mines, FC 'msc'.

These two Ladies will generate 139 MC a turn, and save you another 603 MC worth of resources whilst baking Mark 8 Photon torpedoes! (5) Total gain: 139 + 603 = 742 MC (instead of the 320 MC...)

As the Mark 7 Photon gives the cheapest mine units (remember the 'Cheapest mine unit section above), it might be a good start for saving even more resources. Scoop them up as Mark 4 or Mark 8 Photons, which are generally believed to give you the most 'bang for the buck' (6).

Table 8 gives the total number of resources gained, but these are relative values based on the Perfect Torpedo Conversion listed in Table 4. To obtain absolute values for the total number of resources gained through torpedo conversion, you'll have to devide the totals (table 8) through the number of mine units that was laid (==swept) in the Perfect Torpedo Conversion.

Positive values (green) indicate a net gain in resources. For example: when you lay position 8 torpedoes and scoop them up as position 2 torpedoes, every mine unit will save you 2.062 MC worth of resources.

These values are independent of the number of torpedoes used and are therefore also independent of the Perfect Torpedo Conversion Rate (table 4).

Misc Tips:

• If you want to know what resources you're saving (minerals or MC), compare table 4 and table 6. For example the first option above cost you 144 MC worth of minerals (equals 144/3 = 48 kT of minerals) but saves you 161 MC, adding up to a net profit of 17 MC. Not bad.... :-)
• If you combine this method with the 'Reverse Alchemy' strategy as laid out by Jan Klingele (Sirius) in issue 5 of the Planeteer (7), laying Mark 7 or 8 Photons and scooping them up as Mark 1 Photon torpedoes might turn out to be even more profitable!

These tables were generated by a piece of self-written C++ code. If you want to calculate the torpedo conversion rates of custom ship lists and you don't want to do the computations by hand, drop me a line and I'll send you the code.

And last but not least I'd like to thank Sirius for his valuable comments. Let's play it again, Jan!

I hope this saves you all a couple of MC!

Timo Kreike
[email protected]

(1) Eden Tans site is no longer available, his Infolist can be downloaded here.

(2) To be complete: the values in this table are calculated according to the regular minelaying formula as listed in the second paragraph of this article.

A similar table can be found in the article 'Table Talk' by GammaMark in issue 2 of the Planeteer. The Planeteer Homepage can be found in the Museum.

(3) When considering the Robotic race advantage that enables them to lay 4 times as much mines the values in the table above will change to:

This won't change the conclusion drawn above.

(4) The values in the Perfect Torpedo Conversion Rate have been minimised to obtain the most usable (==smallest) values. For example when a conversion suggests you should convert 100 position 5 torps to 25 position 10 torps, this has been brought back to 4 postion 5 torps ans 1 position 10 torp.
(In this case both values have been divided by 25.)

       100 -> 25   becomes   4 -> 1
        36 -> 16   becomes   9 -> 4 etc.

(5) That is: if you have a use for Mark 8 torps. Otherwise you only have a book gain - that won't help you in any way.

(6) Proving this is out of the scope of this article. If you're interested in an excellent discussion about the weaponry used in VGAP, I suggest reading the 'Master at Arms' paper written by Jan Klingele (Sirius).

(7) The Planeteer Homepage can be found at: http://web.ukonline.co.uk/planeteer.resurrection/