Fenders: Which Style and Why
Fenders are one of those pieces of gear that seem simple until you actually need them. When docking, locking through, or tying up alongside another boat, fenders are the only thing standing between your hull and hard fiberglass, wood, or steel.
Choosing the right style and size matters more than most new boaters expect. Too small and they do not protect much. Wrong shape and they do not sit where you need them.
What fenders actually do
A fender is not just padding. Its job is to absorb impact, spread load, and stay positioned between your hull and whatever you are tied to. On the Rideau, this commonly includes:
- Lock walls
- Fixed docks with little or no height adjustment
- Other boats of varying sizes
- Marina finger docks
That variety is exactly why fender style and sizing matter.
Common fender styles
Cylindrical (straight) fenders
These are the most common and versatile fenders. They can be hung vertically or horizontally and work well against flat docks, lock walls, and other boats.
For most cruisers, cylindrical fenders form the core of the setup. They are quick to deploy, easy to adjust, and predictable in how they protect the hull.
Ball (round) fenders
Ball fenders provide more volume and cushioning than straight fenders. They are especially useful when tying up alongside larger boats, rough surfaces, or uneven contact points.
They offer excellent protection, but they are bulkier to store and are usually carried as supplemental fenders rather than primary ones.
Flat or specialty dock fenders
Flat fenders are designed mainly for docks. They sit securely between the hull and a dock face and tend to stay in position well.
They are less useful for rafting or lock walls and are best thought of as situational tools rather than everyday fenders.
Sizing fenders for our 27 ft cruiser
For a 27 ft cruiser, undersizing fenders is the most common mistake. A cruiser has more freeboard, more windage, and more docking momentum than a small runabout. That means you want fenders with enough diameter to actually cushion the hit and keep the rub rail and hull protected.
Recommended primary size
- Cylindrical fenders: 8.5 inch x 27 inch (good all-around baseline)
- Upgrade option: 10 inch x 30 inch if you expect frequent locks, rough walls, or larger neighbors
If we only pick one size to standardize on, 8.5 x 27 inch is a solid everyday choice for a 27 ft boat. If storage space allows, having at least two larger fenders adds real confidence for locks and unknown docks.
How many fenders
- Minimum for basic docking: 4 cylindrical fenders
- Recommended for marinas + locks: 5 to 6 cylindrical fenders
Four gets you coverage at bow, forward-midship, aft-midship, and stern. Five or six gives flexibility when the dock height is awkward, when we are tied up in a lock, or when we want to double up protection at the widest part of the boat.
Optional add-ons that are actually useful
- One ball fender: extra cushioning for rough walls or rafting
- Two smaller “utility” fenders: handy spares for odd angles or unexpected tie-ups
Why fender height matters as much as size
Even the right fender will not work if it is hung at the wrong height. The goal is for the fender to make contact before the hull does.
On the Rideau, that often means hanging fenders lower than expected because lock walls and docks can be unforgiving. It is normal for part of the fender to sit close to, or just above, the waterline.
Our practical takeaway
For Lucky Enough, a simple and confidence-building setup looks like this:
- Four to six cylindrical fenders, with 8.5 x 27 inch as the everyday baseline
- At least one or two larger fenders (10 x 30 inch) if we have the storage space
- Quick-adjust fender lines so we can change height fast for docks and locks
- Optionally one ball fender for heavy contact situations
This setup covers normal docking, marina stays, and lock transits without guesswork. It is not fancy, it is just the right amount of protection for a 27 ft cruiser.
Do fenders damage gelcoat?
This is a common concern, especially for new cruiser owners. The short answer is no — clean, properly sized fenders do not damage gelcoat. Fenders are designed to protect the hull, not harm it.
When gelcoat scuffing does happen, it is almost always due to grit, dirt, or sand trapped between the fender and the hull, combined with movement. Constant rubbing over time, especially in wind or boat wake, is what creates marks — not brief contact during docking or locking.
The risk is higher during long marina stays where fenders remain deployed for days or weeks. Short-term use while docking, tying up, or passing through locks is not a concern when fenders are clean and sized correctly.
This is why we avoid running with fenders down while underway and why a quick rinse of fenders now and then is a good habit. Soft vinyl fenders that are kept reasonably clean are far gentler on gelcoat than hard contact with docks, walls, or other boats.
In practical terms, fenders are part of protecting the boat, not something to fear. Used properly, they prevent far more damage than they could ever cause.