Dewinterizing Your Boat For Spring Launch

Dewinterizing Your Boat For Spring Launch

It's been a long winter for boaters looking forward to time on the water after a long season of storage. Hopefully, your boat was properly winterized shortly after being pulled from the water last fall, according to this pre-storage checklist published by On the Water magazine:

  • Engine oil & filter changed- If the oil and filter weren't changed prior to storage, definitely take care of that now.
  • Fuel filters replaced- Replace them now if this step was skipped before storage.
  • Fuel tank stabilized- Either totally empty or completely full of fuel to prevent contamination from condensation, with an additive to prevent moisture contamination and fuel separation.
  • Outdrive or lower unit oil changed
  • Outdrive unit removed for inspection and/or service
  • Battery serviced, removed and charged for the winter season
  • Battery cleaned, fully charged and cables removed, wire tied and marked as positive and negative leads if left in the boat.
  • Lubricate shifting cables and steering systems
  • Cover in shrink wrap or a boat cover with large vents to prevent mold from forming inside of the cover.

If these precautions were taken prior to storage, we're ready to move on to the prelaunch preparations for the spring boating season. 

Uncover, Clean, and Inspect

Even a boat meticulously prepared for winter storage should be thoroughly inspected before heading for the water. A good cleaning inside and out also provides the opportunity to inspect for cracks or gouges in the hull as well as for spotting any missing rivets. If your boat bottom paint is the ablative type and is now showing signs of wear from the previous seasons, it might be a good time to give it a fresh coat for anti-fouling protection against marine slime, shell, and weed fouling which can adhere to the hull. A new bottom coat ensures a smooth slick surface to improve fuel efficiency and performance.

Now is the time to clean and polish deck fittings and topsides with a mild detergent. Inspect scuppers and drains and make sure they're clear. While you're doing the windows, check the condition of the wiper blades while you're at it. As you move about the boat check to make sure you have all the tools and onboard spares you'll need, and when you're cleaning and polishing the interior don't forget the bilges. 

Cooling System

Many knowledgeable boat owners drain the cooling system as part of the winterizing process, especially in colder climates, to prevent the coolant line from freezing. Before refilling, make sure to empty and clean the strainer and check hoses for holes or cracks. If you have an outboard engine, check the rubber cooling impeller to ensure that it's free of cracks. Make sure you have a spare supply of extra coolant onboard for emergencies after refilling the system.

Fuel System

If you haven't changed the fuel filters from last season, now is the time to take care of that chore. While you're at it check the fuel lines for cracks, especially if they've been exposed to freezing temperatures. If fuel additives weren't used for a full tank for winter storage the gas is probably stale due to water contamination and or fuel separations, so drain the tank completely. Adding a quality non-ethanol additive when you fill the tank can prevent engine damage from E10 gas. 

Batteries and Electrical

Charge all batteries and if they've been removed, install them. If fluid levels are low distilled water is best for topping off. Coast Guard regulations require that all batteries are properly secured with battery posts covered to prevent corrosion and shock hazards. If wingnuts are used, replace those with stainless steel lock nuts to ensure that cables remain tightly connected and can't loosen. With batteries fully charged and installed, test all cabin and helm switches. The float switch for an automatic bilge pump should also be tested for proper operation.

Check the radio and all gauges for proper operation and inspect antenna condition. Navigation lights, shore power and charger, and wiring should all be checked and inspected. Make sure you have spare bulbs and fuses onboard for all systems.

Engine Preparation

Transmission fluid and oil levels should be double-checked, and the website also recommends that engine zincs be checked and changed and the backfire flame arrestor cleaned, as well as the bilge blower for inboard engines.


Distributors are prone to corrosion over the winter. It's a good idea to remove the distributor cap and check for and remove any corrosion from the contacts, making sure that all connections are hooked back up tightly when you're through.

Engine Belts

Worn belts should be replaced, and there are a couple of easy ways to determine if a belt is worn even if it's not showing wear visibly. Pressing down on the belt will show if the belt has too much "give". The belt tension should be firm with insignificant give or sag. Another sign to look for is soot on or near the belt pulleys which is a definite sign of wear. If you observe any of these symptoms replace the belts.

General Safety Preparations For Your First Launch of the Season

The website provides an extensive checklist for boats, all organized by the various systems to ensure that nothing is overlooked before you take to the water this season. Their checklist for recommended and required safety and lifesaving equipment applies to all boats including:

  • Sound signaling device in working order
  • Check distress signals and expiration date
  • Check Pfds (personal flotation devices)
  • Inspect life rings and cushions
  • Check fire extinguishers and recharge if necessary
  • Check and calibrate the compass
  • Check navigation lights
  • Check charts and replace as necessary
  • Check radar reflector
  • Check and replace or replenish first aid supplies
  • Check bailer and hand pump For Everything You Need to Float Your Boat This Season

At we have great prices and fast delivery on thousands of the marine products you need for safe and enjoyable boating this season. We have alternators, manifolds, boat engine parts and propellers at low prices. Marine electronics include GPS, chart plotters, VHF radios, fish finders, and radar. We have an extensive line of fuel additives to prevent engine damage from E10 with each fill-up.

Our extensive inventory covers all of your marine product needs from the anchor windlass to the engine zinc. We've got gear for foul weather, equipment for the galley, hardware and fittings for the cabin, deck, and dock, and the marine industry's best line of paints and protective coatings to ensure your boat stays ship-shape for years to come. Most orders placed before 2PM ship the same day, so don't hesitate to contact us.