Winterizing your boat is the best insurance policy for a smooth launch next season. A thorough winterization protects your engine, plumbing, and onboard systems from freeze damage, corrosion, and costly repairs. Here’s a step-by-step guide to get your boat ready for the off-season.

Why Winterize?

• Prevents freeze damage to engines, plumbing, and tanks
• Protects against corrosion and mold
• Extends the lifespan of your boat and equipment
• Makes spring commissioning faster and less expensive

Step 1: Prep and Clean

• Remove all gear, food, and valuables
• Clean hull, deck, and interior thoroughly
• Check for any maintenance issues and address them now
• Dry out bilges and lockers

Step 2: Fuel System

• Top off fuel tank to reduce condensation
• Add marine fuel stabilizer and run engine to circulate
• Replace fuel filters if due

Step 3: Engine and Cooling System

• Change engine oil and filter
• Flush engine with fresh water
• Run non-toxic marine antifreeze through the cooling system
• Fog engine cylinders (for gasoline engines)
• Check belts, hoses, and clamps for wear

Step 4: Plumbing and Water Systems

• Drain all freshwater tanks, hot water heaters, and lines
• Pump out and flush holding tanks
• Run non-toxic antifreeze through all water systems, including heads and sinks

Step 5: Electrical and Batteries

• Charge batteries fully and disconnect or remove for indoor storage
• Check battery terminals for corrosion; clean and coat with protectant
• Turn off all electronics and breakers

Step 6: Protect from Moisture

• Use moisture absorbers or dehumidifiers in the cabin
• Open lockers, drawers, and hatches for air circulation
• Check bilge pumps and float switches for proper operation

Step 7: Cover and Store

• Use a quality, well-fitted boat cover or shrink wrap
• Support cover to prevent pooling water and snow
• Store outboards upright and drain lower units
• If storing outdoors, tilt trailer tongue down for drainage

Bonus Tips

• Label all winterized systems for easy spring startup
• Keep a checklist for next season’s commissioning
• Take photos of engine and systems for reference

Need Supplies or Help?

Lighthouse Marine Supply stocks marine antifreeze, fuel stabilizer, filters, moisture absorbers, and more. Not sure what you need? Call 631-722-5700 or email sales@marineengineparts.com for advice.

Final Word

A well-winterized boat saves money, time, and headaches in the spring. Follow this checklist and you’ll be ready to hit the water as soon as the season starts!