Boat & Marine Engine Toolkit

Hull speed to anchor scope in seconds — pro marine calculators that work offshore with no signal needed. No ads, no subscription, one-time unlock.

Boat & Marine Engine Toolkit is a professional calculator suite for boat owners, marine engineers, naval architects, ship captains, and offshore platform crews. Run every calculation fully offline — at the dock, at anchor, or miles from the nearest cell tower. No ads, no accounts, no subscription.

From sizing ground tackle for a blow to checking prop shaft torque before sea trials, the toolkit puts trusted marine engineering formulas in your pocket and keeps them there.

WHAT'S INCLUDED:

Navigation & Anchoring

• Hull Speed Calculator — compute theoretical hull speed and speed/length (S/L) ratio from waterline length for sailboats, trawlers, and displacement craft.
• Anchor Chain Scope — plan rode length from water depth, bow height, and tide for safe overnight holding.
• Anchor Pull Strength — estimate working load on your anchor and rode from wind, current, and vessel windage.

Propulsion & Drivetrain

• Prop Shaft Torque — calculate shaft torque from engine horsepower and shaft RPM for gearbox and coupling sizing.
• Hydraulic Cylinder Force — push and pull force from bore, rod diameter, and system pressure for steering, hatch, and deck gear.
• Fuel Burn & Range — project fuel burn, cruising range, and reserve from tank capacity, GPH, and cruise speed in knots.

Safety & Compliance

• Bilge Pump Sizer — size pump capacity against hull volume with ABYC-aware guidance for peace of mind.
• Bollard Spacing — lay out dock and deck bollards with clean spacing for mooring lines and bollard pull loads.

Reference Tables

• Beaufort wind scale, anchor scope ratios, shackle working loads, and more — the numbers you actually reach for on deck.

WHO IS IT FOR:

• Boat owners planning passages, provisioning, and ground tackle
• Marine engineers sizing drivetrains, hydraulics, and auxiliaries
• Naval architects sanity-checking hull displacement and S/L figures
• Ship captains and mates running quick bridge calculations
• Offshore platform crews and workboat operators on deck
• Marine surveyors documenting condition and compliance notes

WHY MARINE PROS LOVE IT:

• 100% offline — every calculator runs on-device, so you never lose a tool when you lose signal offshore.
• No ads and no tracking — clean, focused screens built for use at sea.
• No subscription — pay once, own it, use it on every trip.
• Instant results — type values, get answers, move on to the next job on the checklist.
• Professional formulas — ABYC-aware guidance, standard naval architecture equations, and clear unit handling (knots, meters, feet, psi, bar, kW, HP).

ONE-TIME UNLOCK: Unlock All Calculators is a single $19.99 USD in-app purchase. It is a one-time, non-consumable unlock — not a subscription. One payment opens every Pro calculator and every reference table, forever, on your Apple ID. Prop pitch planning, shaft torque, bilge pump sizing, bollard pull layouts, Beaufort references — all in.

Stow it in your pocket, keep it on the bridge, or pin it to the engine room iPad. Boat & Marine Engine Toolkit is built to be the quick, quiet answer to the everyday marine engine and offshore questions that keep boats running and crews safe.