HG 1e Capital Ship Design Power Plants pp. 53, 63, and 70

[snrdg121408]

Morning PDT all,

On my second walk through of the Capital Ship Design Example I have managed to confuse myself when calculating the Step 2 Drives Power Plant cost on p. 70.

The Capital Ship Design Example for the power plant tons calculation in the text is off by a factor of 10.

The equation as written is 0.05 x .75 x 7,500 = 281.25 tons not 2,812.5 tons as shown. The value of 7,500 is supposed to be 75,000 tons which is from the hull table on p. 62.

The correct equation is 0.05 x .75 x 75,000 = 2,812.5 tons

Breaking the equation down 0.05 is the % of displacement from the Capital Ship Design Power Plant Table on p. 63, the 0.75 is from the Spacecraft Options Power Plants table p. 53 and the 75,000 is from Capital Ship Design Hull Table on p. 62.

From the Spacecraft Options Power Plants table p. 53 most power plant in use are TL 12-14. The cost per ton of power plant for a TL 12 - 14 according to p. 63 is MCr2.5 per ton and a TL 15+ power plant is 200%.

Power Plant Cost = 2,812.5 x 2.5 x 2 = 7,031.25 x 2 = MCr14,062.5

I decided to use the Capital Ship Design Rules on p. 63 to check the results.

Power Plant Table shows that a plant with a rating of 6 requires 5% of the hulls total displacement in tonnage. A power plant's tonnage a TL 15 a fusion power plant is 25% smaller than ones built between TL 12 and 14. The cost per ton for TL 12+ is MCr2.5

Tonnage:
75,000 x .05 = 3,750 + (3,750 x -.25) = 3,750 - 937.5 - 2,812.5

Cost:
2,812.5 x 2.5 = MCr7,031.25

Comparing the two cost calculations I feel that based on the numbers the power plant rules on Capital ship Design p. 63 matches the example.

Which calculation provides the correct power plant cost p. 53 or p. 63?

 

[AnotherDilbert]

When we are calculating a TL15 power plant manufactured at TL15 tech upgrades (p53) are not available. The calculations only use p63. As you noted that is what the example used, almost.

Size: 75000 * 5% * 75% = 2812,5 dT
Cost: 2815,5 * 5 = MCr 14062,5, oops...

Note that TL15 fusion cost MCr 5 / dT as noted in the table near the end of p63.

 

[snrdg121408]

Hello AnotherDilbert,

When we are calculating a TL15 power plant manufactured at TL15 tech upgrades (p53) are not available. The calculations only use p63. As you noted that is what the example used, almost.

Size: 75000 * 5% * 75% = 2812,5 dT
Cost: 2815,5 * 5 = MCr 14062,5, oops...

Note that TL15 fusion cost MCr 5 / dT as noted in the table near the end of p63.

HG 1e softcover p. 63 does allow for TL 15 Power Plants per the fourth note below the Power Plant Table: TL 15+ fusion plants are 25% smaller. Unfortunately, there is no mention of what the cost per ton in the notes for TL 15.

The HG 1e PDF p. 63 also allows for TL 15 Power Plants per the fourth note below the Power Plant Table: TL 15+ fusion plants are 25% smaller but cost twice as much. The PDF also contains the TL 15 Fusion MCr5 note as you indicated in reply.

I did however for some reason pencil in that a TL 15 Fusion plant cost MCr5 per ton. Apparently I either did the correction based on p. 53 or more likely after comparing the PDF with the softcover. Unfortunately, I failed to check the PDF otherwise I would have posted a note that the Design Example's Power Plant Cost may have been miss calculated.

The equation to get the cost for the Capital Ship Design Example Step 2 - Drives p. 70 should probably have followed the Capital Ship Design Drive Power Plant Rules on p. 63.

Size: 75000 * 5% * 75% = 2,812.5 tons
Cost: 2815,5 * 5 = MCr14,062.5

Thank you for clearing up my confusion and squaring away my softcover HG 1e. Now if I can remember to cross-check with the PDF, ensuring I scroll to the bottom of the page, and Traveller HG Errata I might get a handle on the old design rules in time to have a go with the new ones.