Boat Fenders , Fender Use and Maintenance

Protecting floating objects

Boat Fenders provide rugged protection and convenient storage for boats of all sizes.

A fender includes an inflatable body is partially filled with water, a port sized to receive the water into the body and a plug adapted to seal the port.

The partially filed fender floats in the water with a lower portion extending and remaining below the water even during wave action, leaving the bottom portion of the fender to protect a portion of a floating object that extends below the waterline.

The best places to tie fenders

Many boaters and skippers are in the habit of tying boat fenders to the lifelines. After all, it's easier than bending down to tie the fenders to the base of the stanchion. In Fact , some Fenders Manufacturers companies make clips that help you clip your fenders onto the life-lines without tying them each time.

Lifelines are strong but when subjected to great loads, the lines and fittings can be broken or stretched. Also, the leverage imposed by exerting force at the top lifeline can break or bend the stanchions.

There are several things to consider here: First, when you're alongside a dock or rafting up with another boat, surge can cause an up-and-down or rocking movement along the line of contact. That movement can generate great force against the fender and, subsequently, against the lifelines.

Some skippers will even tie fenders to their cabintop grabrails. While this is a better solution than tying to the lifelines, You have also seen grabrails break when a heavy surge and the subsequent mating of two hulls dragged a fender down between the boats.

Boat Fender Use and Maintenance

Most boaters don’t usually give their fenders much thought, neither their use nor maintenance. Boat Fenders are tied on, thrown over the side of the boat and adjusted in the hopes they’ll keep the boat’s hull off the pilings and dock. Then they’re usually forgotten until it’s time to take them up when leaving the slip.

boat’s hull protecting

Protecting your boat’s hull is the primary purpose of fenders, and this can be a fine art and especially if your boat is docked in an area with a tidal range and some exposure to weather or swell. Whether you’re a day sailor and keep your boat in the same place every day or you’re a cruiser in a different slip every night, you need to know what the tidal range is for your area and what the dock’s exposure is to weather, current and swell. Another consideration is whether or not the dock is fixed or floating your fender location will vary for optimum protection.

Using Fenders

If your boat always returns to the same slip, the ideal solution may be fenders that are permanently affixed to your dock, whether it's fixed or floating. These are especially helpful to singlehanders. Because these fenders are affixed to the dock, we advise seeking permission from the dockmaster prior to purchasing and installing them.

Most fenders, because of their cylindrical or round shape, roll, and the longer the line tying them, the larger an area they can cover as they roll. Tying fenders to the lifelines places strain on the lifelines and it also requires long lines, allowing the fenders to roll more easily. This lets them extricate themselves from their desired location and leaves the side of the hull unprotected. A better attachment point is the stanchion bases and on sailboats, outboard genoa tracks or the standing rigging. Large boats often have a row of small cleats on both side decks installed specifically for fenders.

Safety systems - Lifeline terminal types, Terminations, Cables, Stanchions and Accessories

To protect your hull against boat motion along a horizontal hazard such as the edge of a dock, orient the fender vertically by hanging it from the edge of the hull. This allows it to roll along the dock edge at all times. You'll need to adjust it for tidal range, however. Where the object to be protected against is vertical such as a piling or post, turn the fender horizontally and secure it from both ends. Orienting the fender so that it can roll along the hazard makes it more effective.

The number of fenders

The number of fenders you carry depends on the type of boating you do. Small boats that only use fenders for visits to a well protected fuel dock may need only one or two. Long-distance cruisers who may face a wide variety of docking situations should have a minimum of six fenders. Boats routinely docked in storm-prone areas, in berths marginally narrow for the boat’s beam or where rafting boats is a common practice may need up to a dozen fenders. Use your own judgment, and remember that fenders are much less expensive than hull repairs.


Consider flat fenders if you moor in an area where there’s constant swell or wake from other boats. These closed cell foam won’t roll and are easy to store in a locker. They can also be used as swim boards, kneeling pads and seat cushions.

Fender boards allow your boat to move in its slip, around pilings or other protrusions, without constant adjustment of individual fenders. Making fender boards is easy, it requires a minimum of two fenders and a board that's a minimum 2” x 6”, and 4' to 6' long.. The board is suspended horizontally over the two fenders.

As for tying fenders on, the clove-hitch or two half-hitches are the best knots to use. For the knot-challenged, fender clips or cleats make using and adjusting fenders simple.

Fender Maintenance

Check fender air pressure occasionally, either with an air pressure gauge or by measuring the circumference. Both measurements should be on the fender or in the manufacturer’s product information. Fenders that are overinflated become rigid and can mar your hull; underinflated fenders are too soft to provide adequate protection.

Waxing your PVC fenders will help them repel everyday dirt and grime. If you need to clean them, use soapy water. Add a mild abrasive to your rag such as Bar Keepers Friend or Bon Ami for tougher stains and marks, but don’t scrub too hard. If this level of scrubbing doesn’t clean, try an abrasive cleaner like Comet, but once again, scrub gently. There are commercial products available for cleaning fenders and mineral spirits can also be used for really tough stains. Don’t use acetone or lacquer thinner these chemicals will simply dissolve the vinyl, leaving a sticky residue, they’ve also been known to eat the vinyl completely away.

While you’re cleaning, don’t forget to inspect and clean the lines on the fender. A good rinse usually flushes away dirt and sand picked up from the dock. If your lines have fallen in the water and become barnacle-encrusted or are chafed or worn, replace them.

Fender covers protect your vinyl fenders from damaging UV rays, keep much of the dirt and grime off of them and are easier on the hull. Covers will also hide the marks on the fenders you’ve not been able to remove with cleaning.

Stowing fenders in a locker or down below keeps them out of the sun, salt and dirt, but few boats have enough space for six fenders or more. Fender baskets that attach to the bow and stern rails are popular on powerboats and large sailboats for this reason. Never leave your fenders dangling over the side when you are underway unless you are approaching or just leaving the dock, it’s not only a mark of poor seamanship but subjects the fenders to additional abuse.

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Safety systems - Lifeline terminal types, Terminations, Cables, Stanchions and Accessories