PSC -> magnetic when you don' t know the magnetic (or don't assume PSC = magnetic)

Not "technically" - PSC is not the magnetic heading. PSC adjusted for deviation is the magnetic heading. One needs to 'swing the compass' in advance in order to build the deviation table. Do not try to work nav problems backwards to get the deviation - that's not a real world option. We are given a deviation table for the problems. In the real world, one would either use the ship's deviation table, or they would create one using a hand bearing compass and/or charted ranges. For this problem, the actual course sailed out of the harbor isn't important - that's why we're plotting lines of bearing.

The setup for this problem has one confusing aspect for me. We say in the problem that the ship is heading 180° psc. Why isn't this converted to true in order to plot on the map? All the other courses that are measured psc are converted to true... yet on the chart with the answers, the ships course is shown at 180° true. If I convert the 180° psc heading to true, I get 164°. The conversion: T: 164° V: -14° W M: 178° D: -2° W (from the problem's deviation table) C: 180° (from the problem setup) Should this ships course not be converted from psc to true? Why? If different than the bearings to marks, why do we handle ships course different from the bearings on marks? Notably, if you drive 164° from the start point you end up driving right over Stone Reef, which added another layer of confusion to this problem set up. Sidenote, the conversions for all the bearings on the marks were very straight forward and I calculated those successfully. Which means regardless of the ships heading I was able to arrive at the correct answer just from the LOP. Not trying to toot my horn, just confirming for the next person that may have the same question: the ships course "doesn't matter" for the purposes of calculating a position from the bearings on the marks.