ESIESSENTIAL SHIPYARD INDUSTRIESTool · Shaft Go / No-Go
ESI
Decision Tool · ABYC P-6-2021 straightness table

Shaft Go / No-Go — runout & scoring

The allowable runout is read live from the ABYC P-6-2021 / Aqualoy straightness table for your length, diameter and acceptance basis — not a flat number. Enter the feeler reading and the call grades ACCEPT → CAUTION → REJECT.

ABYC P-6-2021Live spec by length
FeelerReal readings
AQ19Default material
Allowable runout—
Out-of-round limit (dia)—
Bearing clearance (dia)—
Acceptance basis—

📐Readings

Result
—
Enter readings
0% of allowable runoutlimit
Allowable runout (table, this length)—
Your runout reading—
Allowance used—
Runout verdict—
Out-of-round verdict—
Surface / scoring verdict—

    Straightness is read from the ABYC P-6-2021 / Aqualoy table by length (same table across Aqualoy grades). Diameter sets the out-of-round limit & bearing clearance; material/basis sets the acceptance column.

    How the call is made

    Basis & sources

    CheckRule usedSource
    Runout / straightnessAllowable TIR read live from the straightness table by free length (industry vs Aqualoy-as-new column). Reading graded as a fraction of allowance.ABYC P-6-2021 / Aqualoy straightness table
    Out-of-roundBy diameter: 1–<1.5″ .0015″ · 1.5–2″ .002″ · >2–4″ .003″.ABYC P-6-2021 / Aqualoy diameter table
    Bearing clearanceBy shaft size (Navy BuShips): ¾–1-3/8″ .003–.008″ · 1-7/16–1-7/8″ .004–.010″ · 2–2-3/8″ .006–.012″.Aqualoy / U.S. Navy BuShips 810-1385664
    Surface / scoringLip seal needs a smooth shaft; any groove in the seal band → CAUTION/REJECT.GLIDE lip-seal requirement (shop policy)
    Corrosion / pittingAutomatic REJECT. Crevice/pitting corrosion seeds cracks that propagate and fail under load — a new, higher-torque engine loads the shaft harder.Shop policy / surveyor practice
    Honest note.Per ABYC P-6-2021 the straightness tolerance is essentially length-driven and common across Aqualoy grades ¾–8″ — so the runout limit moves with length (and the chosen basis), while diameter genuinely drives out-of-round and bearing clearance, and material drives corrosion/strength. The tool reflects the standard rather than inventing a material-specific straightness curve. Have ESI engineering ratify the acceptance basis.

    Sources: ABYC P-6-2021 (Propeller Shafting Systems) · Aqualoy / Western Branch Metals shafting tables · SAE J755

    Quick reference

    Field method

    📏Length & diameter

    Free length between supports sets the straightness allowance; diameter sets out-of-round & bearing clearance.

    📐Runout (TIR)

    Support & rotate; find the largest feeler blade that fits — that's your reading.

    🔎Scoring & corrosion

    Inspect the seal band; feeler any groove for depth. Any pitting / crevice corrosion = reject.