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Two marine & boating tools, side-by-side. See which fits your task.
Marine & Boating
Calculate shaft alignment tolerances from shaft length and diameter.
Open Shaft AlignMarine & Boating
Calculate stern drive gear ratio from engine RPM and prop speed.
Open Stern GearYour specific task is calculate shaft alignment tolerances from shaft length and diameter. Open the page, drop your input, get the result — typically under a second.
Your goal is calculate stern drive gear ratio from engine rpm and prop speed. Same approach: paste in, get the result, move on. No account, no upload.
Both tools live in the same category, so the choice depends on the exact subtask. Shaft Align focuses on calculate shaft alignment tolerances from shaft length and diameter; Stern Gear focuses on calculate stern drive gear ratio from engine rpm and prop speed. Try whichever description matches your goal more closely — they're both free.
Yes — both tools are free for unlimited personal use. The Pro plan unlocks higher limits and batch features but the core functionality stays free forever.
Absolutely. Many users chain multiple tools together — process a file with one, then feed the result into another. Nothing is uploaded, so chaining is essentially instant.
No. Both Shaft Align and Stern Gear work without signup. We only ask for an email if you decide to subscribe to a paid plan.