Validation

Mandatory fields, blocking errors, non-blocking warnings, and how Settings limits drive the warnings.

The form has two layers of validation: blocking errors (you can’t submit until they’re fixed) and non-blocking warnings (you can submit, but the value is outside the configured range and someone will ask about it).

Mandatory fields (blocking)

Mandatory fields are marked with a blue left border on the input. If a mandatory field is empty or invalid when you click Submit:

• An inline error message appears below the field
• The Submit button is blocked until the error is cleared

Examples on the Noon Report:

• Voyage Number, Location, Date/Time + GMT offset
• Latitude, Longitude (must parse as DMS)
• Vessel Condition
• Port (when In Port)

Each mandatory field is keyed off the HTML required="" attribute and styled by a mandatory CSS class.

Format errors (blocking)

Some fields enforce a format on top of being non-empty:

Field	Expected format	Error if wrong
Latitude	DD MM' SS" N/S	”Invalid latitude format”
Longitude	DD MM' SS" E/W	”Invalid longitude format”
Date	YYYY-MM-DD	”Invalid date”
Time	HH:MM (24h)	“Invalid time”
Numeric fields	Numbers only	”Must be a number”

The form auto-formats DMS strings on tab-out where possible — type 6 1 54 N and it becomes 6 1' 54" N.

Auto-calculated fields (read-only)

These can never be wrong because you can’t type into them. Fix the inputs that feed them:

Field	Formula
Slip %	(observed_distance − engine_distance) / observed_distance × 100
Reported Speed	observed_distance / steaming_hours
Average RPM	main_engine_revs / (main_engine_hours × 60)
Average KW	main_engine_kwhrs / main_engine_hours
Mean Draft	(fwd_draft + aft_draft) / 2
Generator KWhrs	generator_hours × average_kw

Validation limits (non-blocking warnings)

The Settings panel has a Validation Limits section with collapsible groups. Each group lets the office configure a per-vessel Min and Max for parameters like Reported Speed, Bilge Water ROB, BDN Quantity, etc.

Validation Limits — per-parameter Min/Max for each vessel.

When the crew types a value outside the configured range:

• An orange warning appears next to the input
• The form does not block Submit — the warning is informational

The reasoning: limits exist to flag suspicious values, not to enforce them. If a vessel legitimately has a 30-knot speed in storm-following conditions, the Master can still submit.

Configurable groups

Group	Parameters
Draft & Displacement	Fwd Draft, Aft Draft, DWT, Displacement
Speed & Distance	Reported Speed, CP Speed, Observed/Engine/Speed Log Distance
Main Engine	ME Hours, Revs, KWhrs, Average KW, ME Output, Steaming Hours
Generators & Auxiliary	Gen 1–4 Hours/KWhrs, A/E Sea Load, Aux Boiler, Incinerator, FW Generator
Tanks & ROB	Bilge Water, Sludge, Fresh Water, Slops
Lub Oil ROB	High TBN, Low TBN, ME Crankcase, A/E Lub Oil
Fuel ROB	HSFO, LSMGO, VLSFO, VLSFO (≤80 cSt)
Weather	Air Temp, Sea Temp, Bar Pressure, Avg Cargo Temp, Heading
BDN Quantity (MT)	Per fuel grade
Fuel Density (kg/m³)	Per fuel grade
Sulphur Content (%)	Per fuel grade
Viscosity (cSt)	Per fuel grade

Both Min and Max are optional — leave a field blank to disable that bound for that parameter.

Setting limits per vessel

This is a shore-side task done once per vessel:

1. Open the form on the office machine
2. Click the gear icon → Settings
3. Expand each group, type Min/Max for each parameter
4. Click Save & Apply
5. Click Export Configured HTML to download a vessel-specific copy with the limits baked in

The downloaded file is what gets sent to the vessel. localStorage is per-machine and per-file-path, so the limits won’t travel unless they’re exported into the HTML.

See History setup → Part 1 for the full office-side configuration walkthrough.

Cross-field validation

A few fields validate against each other:

• Steaming Hours ≤ Main Engine Hours — steaming time can’t exceed engine running time
• Engine Distance ≤ Observed Distance — slip can’t be negative
• Mean Draft = (Fwd + Aft) / 2 — auto-recomputed
• Generator KWhrs derives from Hours — typing one updates the other if Average KW is set
• Aft Draft − Fwd Draft = Trim — informational only

These produce inline errors when violated.

Error UI

• Red inline message below an input → blocking error
• Orange badge or border → non-blocking warning (Settings limit)
• Grey input → auto-calculated, read-only
• Blue left border → mandatory field

See also

• Submitting — what happens after validation passes
• Setting up history.json → Part 1 — how the office configures limits and exports the form