The right storage place for your boat depends on climate, boat type, hull material, budget, access needs, storm exposure and how thoroughly the boat is winterized. Dry storage can reduce sinking risk and give the hull a chance to dry, but boats stored ashore may be more vulnerable to sudden freezes. Wet storage can make spring access easier, but it requires dependable bilge pumps, dock lines, chafe protection, bottom paint and monitoring.
We'll walk you through your main storage options and the tradeoffs of each one.
Wet vs. Dry Storage
When considering wet versus dry storage, start by penciling out the costs in financial terms. How much does it cost to keep your boat in the water all year long versus six months “in” and six months “out”? In addition to dockage or storage charges, factor in haulout fees, blocking, winterization, bottom paint timing, cover or shrink wrap cost, storm exposure, access for maintenance and insurance requirements.
Wintering “on the hard” may make financial sense in the long run. Fiberglass boats stored on land have a chance to dry out, and for this reason develop fewer osmotic blisters due to water getting into the fiberglass laminate compared to boats stored in the water. Osmotic blisters form when water migrates through the gelcoat and into the fiberglass laminate, where it reacts with soluble materials in the laminate to form acidic solution pockets that push outward against the hull surface. Blister repairs require extensive grinding, drying, and barrier coat application and can cost thousands of dollars on a mid-sized boat — storing the hull out of the water for the winter months reduces the cumulative exposure time that allows blistering to develop.
Although wet storing your boat might give you an early start on boating in the spring, if your boat’s bottom needs painting, consider dry storage. Many of today’s bottom paints, such as copolymer ablative paints, do not oxidize in air, so you can paint in the fall and be ready to splash in the spring without a second haul.
Dry-stored boats don’t sink. A boat stored on land is not dependent on a bilge pump, shore power, batteries or dock-line adjustment to stay afloat. That alone makes dry storage attractive for owners who cannot check the boat frequently. Dry storage also makes it easier to inspect through-hulls, transducers, running gear, zincs, trim tabs, outdrives and hull damage before spring launch — with the boat on stands, every inch of the underwater hull is accessible without diving gear or a diver.
Dry storage is not risk-free. As BoatUS has noted in regard to insurance claims:
“The vast majority of claims in temperate states involved boats that were being stored ashore. Since water retains heat longer than air, boats surrounded by air are more vulnerable to a sudden freeze than boats surrounded by water. Even a brief cold spell that lasts only a night or two can do considerable damage. In temperate states, boaters must winterize engines and freshwater systems especially when boats are stored ashore. In deep freeze states, boats stored ashore must be winterized earlier than boats stored in the water.”
The bottom line is that if any chance of freeze damage exists, you need to either winterize your boat or implement measures to prevent damage should a freeze occur. Engines, freshwater systems, heads, washdowns, livewells, pumps, strainers and air-conditioning systems can all hold water.
Antifreeze is typically available in -50°F, -60°F, and -100°F burst ratings, each tinted a different color to make it easy to tell them apart at a glance. Coloring the antifreeze also makes it easier for you to tell when all the water has been flushed out of the system you are winterizing. If the liquid is still clear or is a lighter color than the undiluted antifreeze, then you know there is still water in the system.
We'll walk you through your options and help you choose the right antifreeze for your region and your boat.
Antifreeze Applications
The main applications for antifreeze on a boat include winterization of potable water systems, sanitation systems, engine raw water cooling systems, non-running engines, and air conditioners. Selecting the right product requires knowing which system you are protecting — not all marine antifreezes are interchangeable across applications.
Our West Marine Engine & Water System Antifreeze is available in -50°F, -60°F, and -100°F burst ratings and is made using non-toxic pure virgin propylene glycol which makes it ideal for winterizing potable water systems, raw water cooling circuits, sanitation systems, and non-running engines during layup. Because this product does not contain the corrosion inhibitor additive package required for engine coolant service, it should not be used in running engines as a coolant. It is, however, safe for any system where it may come in contact with drinking water.
Freeze Point vs. Burst Point
The burst point (shown as -50°F, -60°F, -100°F, etc.) is the temperature at which a sealed copper pipe filled with the undiluted product will burst from ice expansion. Burst points are a standard created by the plumbing industry in the 1930s to indicate the structural protection strength of an antifreeze product. This is the rating printed prominently on the label.
The freeze point is the temperature at which ice crystals (slush) begin to form in the undiluted product. At the freeze point, the liquid begins to solidify into slush but does not expand with enough force to burst pipes or damage plumbing. Slushing is not harmful to engine or potable water systems.
The practical implication is that a product rated to a -50°F burst point may have a freeze point of only +12°F to +16°F. If your winters regularly drop to 0°F, a -50°F burst-rated product still protects your plumbing because the freeze point is irrelevant — what matters is whether the ice expansion can burst pipes, and a -50°F burst rating means it cannot until that extreme temperature is reached.
Getting all of the water out of your potable water systems, sanitation systems, engine raw water cooling systems, non-running engines, and air conditioners is essential to protecting your boat from costly freeze damage over the winter months. Fortunately a few simple steps and a few gallons on non-toxic antifreeze can handle all of the systems on your boat.
Top 5 Tips for Winterizing Your Boat's Potable Water System
1. Drain the Entire Freshwater System First
Empty the freshwater tank, water heater, pumps and plumbing as completely as possible before adding antifreeze. Less water means better freeze protection.
2. Use Only Non-Toxic Marine Antifreeze
Protect potable water systems with propylene glycol antifreeze designed for boats. Never use automotive (ethylene glycol) antifreeze, which is toxic and can contaminate your freshwater system.
3. Run Antifreeze Through Every outlet
Open each faucet—hot and cold—along with showers, transom water taps, cockpit sinks and any other freshwater fixtures until pink antifreeze flows from every outlet.
4. Don't Forget the Water Heater
Drain the water heater completely and, if equipped, use a bypass kit so you don't waste several gallons of antifreeze filling the tank.
5. Protect Pumps and Filters
Be sure freshwater pumps, strainers, accumulator tanks, filters and ice makers (if equipped) are filled with antifreeze, since trapped water in these components is especially vulnerable to freeze damage.
How to Winterize a Marine Engine Cooling Systems
Your first step is determining what type of cooling system your boat has: a raw water cooling system or a closed cooling system.
Raw water cooled engines pull lake, river, or seawater directly through the engine block and exhaust system before discharging it overboard.
Closed cooling systems use automotive-style coolant circulating through the engine while raw water removes heat through a heat exchanger.
Even though the engine block contains coolant, the raw water side of the system must still be winterized.
How to Winterize a Sterndrive Engine
Step 1: Warm the Engine
Run the engine until normal operating temperature is reached. This ensures the thermostat opens and treated fuel circulates throughout the system.
Step 2: Introduce Antifreeze
Connect the winterization kit and begin feeding undiluted marine antifreeze through the cooling system.
Continue until antifreeze is visibly exiting through the exhaust outlet.
Step 3: Fog the Engine
Once antifreeze is circulating, apply fogging oil through the carburetor or intake system while the engine continues running.
Heavy white smoke is normal during this process.
Step 4: Shut Down and Inspect
After antifreeze and fogging oil have fully circulated, shut down the engine and continue with oil changes and inspections.
Winterizing an Inboard Engine
Winterizing an inboard engine is slightly different than winterizing a sterndrive engine becase the raw water intake is connected through a seacock
Step 1: Close the Seacok
Step 2: Disconnect the Raw Water Intake Hose
Step 3: Insert the Hose Into a Bucket Filled with Marine Antifreeze
Step 4: Start the Engine
Step 5: Continue Running Until Antifreeze Exits the Exhaust
Step 6: Fog the Engine
Reconnect the Intake Hose
Reopen the Seacock
Always verify that sufficient antifreeze has circulated through all cooling passages before shutting down.
Changing your oil before winter storage matters because contaminants in used oil — acids, moisture, combustion byproducts — can corrode engine parts over the long storage period. Fortunately, doing the job yourself is relatively easy with the right tools.
Tools & Products You Need to Change the Oil on an Inboard or Sterndrive Boat
- Correct marine engine oil meeting manufacturer specifications
- Replacement oil filter
- Oil extraction pump or drain system
- Oil absorbent pads or cloths
- Funnel for clean refilling
- Oil filter wrench
- Container for used oil
- Protective gloves and safety gear
How to Choose the Right Oil for Your Boat
Your engine manufacturer will list the recommended oil for your engine in your owners manual. Oil containers list the rating and viscosity of the oil on the front of the container so getting the right oil is as easy as matching what is in your manual to what is on the oil container when you go to buy.
Pay close attention to all letters and numbers listed in your owners manual as oil that is great for a gasoline engine may not work in a diesel engine and vice versa.
How to Change the Engine Oil On an Inboard or Sterndrive Engine
While changing the oil on your boat is more complicated than changing it on your car, with the right prep and the right tools you can make it as easy as possible. We'll walk your through it step by step.
Step 1: Run the Engine First
Warm oil is thinner so it is easier to withdraw through whatever method you use—especially if you’re using a dipstick tube. Plus, running the engine mixes all the gunk and contaminants into suspension, so you’ll be able to get all of the dirt out of the engine.
Step 2: Extract the Oil Using an Oil Change Pump
Most manual and electrical oil change pumps remove the oil from the engine using a skinny tube that feeds through the dipstick tube on your engine. Follow these steps to remove all oil from the engine.
- Remove dip stick, wipe it down and set it aside
- Feed the extraction tube down the dip stick tube as far as it will go
- Pump the oil out
- Pull the extraction tube out once all engine oil is removed and put the dipstick back in
Step 3: Change Your Oil Filter
You should always change your oil filter when changing the oil on your boat. Your oil filter will still have old oil it which will contaminate your fresh oil once it starts circulating.
- Remove the old oil filter. Make sure you have something underneath the oil filter to catch any oil in the filter that spills
- Lightly coat the gasket on the new oil filter with clean engine oil
- Hand tighten the filter on the engine giving it a three-quarter turn beyond the point where the seal makes contact with the flange.
Step 4: Refill Your Engine Oil
Refill your oil according to the engine manufacturer specifications. Owner's manuals usually specify the oil capacity, but you should check your oil level before running the engine to make sure the level is adequate. Make sure you have a funnel on hand as well to avoid spills when refilling.
Step 5: Run the Engine and Check Oil Level Again
Start your engine and let it get up to operating temperature then shut it off and wait 5-10 minutes before checking the oil level again to make sure it's correct. If it is low, top it off.
How to Change the Oil on a 4-Stroke Outboard Engine
Step 1: Run the Engine First
Before draining, attach flushing muffs to a garden hose and place them squarely over both sides of the water intake. Turn on the water, start the motor, and allow it to run for a few minutes to warm the oil and suspend the contaminants. Then shut off the motor and remove the flushing muffs.
Step 2: Drain the Oil
Most four-stroke outboards have an oil sump drain plug below the crankcase at the back or side of the motor’s leg. Position a catch pan under the motor before removing the drain plug. While some mechanics extract oil through the dipstick tube, this method does not remove all the oil — follow the manufacturer’s instructions for a complete drain.
Step 3: Change the Oil Filter
After draining the oil, remove the oil filter. Most are spin-on type, similar to those used on automotive engines. Filters that have taken a set may require an oil filter wrench for removal. Install an OEM or equivalent replacement filter — before installation, lightly coat the filter’s O-ring with clean motor oil, then screw it on until hand tight.
Step 4: Fill the Crankcase with New Oil
After installing the new oil filter, fill the crankcase with fresh oil. Consult your owner’s manual for the correct viscosity, quantity, and API service level required. Do not exceed the maximum fill level on the dipstick.