Inshore race analysis and debriefs

Make the next practice count

Months ahead, choose the event your season is building toward and a goal the crew shares. Nearer the start, focus on what still needs rehearsing. If you have two practice days and often lose your lane after the start, we can use that question to shape the sessions with your crew or coach.

Agree who calls time, traffic and changes in pressure, and discuss the next move if the first plan fails. After sailing, keep one useful observation and the next thing to test. The debrief then becomes a starting point for the next regatta.

Comparing maneuvers fairly

A tack review covers the approach through to speed recovery on the new course. Entry speed and time spent turning affect the total loss. Comparing only the lowest speed can favor a maneuver that preserves speed briefly but takes much longer to settle.

The Exile study lines up recorded turns around the moment the boat passes through the wind. It shows boat speed before, during and after each turn, across several instrument sources, including practice and transit. Speed through water and speed over ground are kept apart, so current is not mistaken for a change in the boat’s performance.

In that study, recovery is judged against the speed the boat carried into the turn, within a fixed observation window. A turn that does not get back to that speed within the window is reported as not recovered.

Speed lost is measured against the chosen reference. Distance lost to a rival or to the mark also depends on the route and the rival’s track. The crew’s reason for maneuvering helps explain whether the loss was worthwhile.

With a coach, we can review handling across comparable turns and choose one change to test at the next session. Comparisons should stay within similar wind ranges and maneuver conditions.

Starts and mark roundings

At a start, we can examine the final acceleration, distance to the line and heading, then follow the boat to see how long it keeps its lane. A precise timing comparison needs the line geometry and a verified start signal time aligned with the recording.

To understand whether traffic forced a turn, we need more than the boat’s own GPS track. Fleet tracks can show the space between boats; video and notes made at the time can help establish what the crew saw. We label any course lines or race boundaries that are not confirmed.

A short mark approach may require a slow turn or leave the boat behind traffic. We compare the approach and rounding through to speed recovery and the first available lane on the next leg.

In this replay, follow one boat through the start or a gate rounding, then select a nearby boat and inspect the same interval. Compare the approach with the speed and heading after the turn.

The twelve Chicago J/88s shown here are a simulation built on Exile’s sailing data. In the replay, Exile is shown on the winning track. The replay does not represent historical results or rankings of the named crews.

Boat speed and performance

For steady sailing comparisons, we only set like against like: similar wind, sail configuration, sea state and recent maneuvers. Averaging across different conditions can hide a pattern or suggest an improvement caused by the conditions.

The Exile analysis compares measured speed across wind strengths and angles, tack by tack, and only where there is enough data on each tack. Readings taken close together in time are not independent, so a short run of samples counts for less than its length suggests. Differences between tacks may warrant checking calibration or trim, though the speed measurements alone cannot identify the cause.

An observed polar describes the sailing represented in the recordings. Sparse wind bands and missing angles remain gaps. For a routing polar or training target, we also need to assess what the crew can sustain with the intended sails. We compare that target with the observations before proposing changes.

The TP52 study applies the same maneuver and wind comparisons to eight recorded sessions. The performance research collection also includes coastal records with different channel coverage. Each study documents its available measurements and exclusions.

Planning the debrief

We select sessions around your question. Inconsistent tack recovery calls for several comparable turns; losing a lane after the start requires a closer look at traffic. A polar target that is hard to sustain needs steady sailing records in the relevant wind range.

A debrief can include annotated traces and the crew’s explanation of selected events, with exclusions documented. A coach can use these to plan an exercise with a consistent entry condition and one handling change, then compare the measurements afterward.

If the recordings leave the cause uncertain, we can plan what to record next. For example, missing wind data may prevent a polar analysis even when there is enough information to review timing. We can use the timing measurements in the debrief and plan another recording for the polar analysis.