How to Fender a Boat for Rafting Up: Placement, Size and Etiquette

When rafting up, place the largest suitable fenders where the two hulls will actually touch—normally around the widest sections and any mismatched bow or quarter—and secure the boats with bow and stern lines plus springs that prevent fore-and-aft surging. Do not rely on a row of small fenders or lines led only to the inside boat.

The outside boat should approach slowly and under control, with fenders and lines prepared on the contact side. Once alongside, adjust the boats so masts, spreaders, rails and rubbing strakes cannot clash as they roll. Where the raft is secured to shore or a mooring, appropriate lines from outer boats may need to share the load rather than leaving it all on the innermost vessel.

This guide covers preparation, placement, line arrangement and etiquette. It complements our general boat fender attachment guide.

Key facts at a glance

• Prepare fenders and lines before entering the final approach.
• Use fewer substantial, correctly placed fenders rather than relying only on many small units.
• Protect the widest contact zone and add targeted coverage at a mismatched bow, quarter or rubbing strake.
• Avoid lining up masts and spreaders where rolling could cause contact aloft.
• Bow and stern lines hold the boats together; forward and aft springs control fore-and-aft movement.
• Where required, run lines from outside boats to shore or the mooring so the inside boat is not carrying the entire raft.
• Keep emergency access, companionways, exhausts, outlets and lifelines clear.
• Recheck fenders and lines after the wash of passing traffic, a wind shift or significant tide change.
• Move across neighbouring boats quietly, use agreed routes and avoid stepping on hatches or varnished surfaces.

What should you agree before the approach?

What size and type of fenders work best for rafting?

Rafting often benefits from more diameter than a routine smooth-pontoon berth because both boats can move and roll. The selected fender must bridge hull curvature and remain between the topsides through the expected movement.

• Cylindrical fenders: useful for broad side coverage and easy vertical adjustment.
• Round fenders: useful at a high-load bow or quarter and where substantial stand-off is required.
• Chubby fenders: provide larger diameter in a compact length and can suit focused contact points.
• Deflatable fabric fenders: allow large occasional rafting protection to be packed down after use.
• Fender board systems: may be appropriate for rough pilings or structures, but require competent rigging and are not a substitute for suitable fenders between two boats.

Start with the fender size guide, then account for the larger boat, displacement difference, freeboard mismatch and forecast conditions. If one boat is substantially heavier, the smaller boat’s normal marina fenders may not offer adequate stand-off.

Where should fenders be positioned between two boats?

1. Identify the true contact line. Look at the widest part of each hull, rubbing strakes, tumblehome, flare and topside fittings.
2. Place primary fenders through the parallel midships zone. They should remain between the hulls as the boats roll.
3. Add a larger fender at the vulnerable bow or quarter. This is especially important when boats differ in length or shape.
4. Set the height for hull-to-hull contact. A pontoon height learned at the home berth may be wrong for another boat’s freeboard.
5. Stagger attachment points if needed. Fenders from both boats can alternate, but avoid a tangle of lines and hard fittings.
6. Keep fenders away from windows, skin fittings, exhaust outlets and delicate graphics.
7. Check aloft. Offset the boats so masts, spreaders and rigging cannot touch during roll.
8. Observe the first period of movement. Reposition any fender that rides up, shoots fore/aft or becomes trapped beneath a rubbing strake.

Which lines are needed in a raft?

The exact plan depends on vessel size, cleat positions, shore geometry and local instructions. In principle, the pair of boats needs lines that hold them together and springs that prevent relative fore-and-aft movement. The complete raft also needs an appropriate connection to the berth, mooring or shore.

Use mooring lines appropriate to the boat and expected load. Fender lines are for suspending fenders, not securing the raft. If your fender lines need replacement, compare purpose-made fender ropes.

Step-by-step rafting approach

1. Obtain permission and agree the side, approach and line plan.
2. Brief the crew and prepare correctly sized fenders at the required height.
3. Rig bow line, stern line and at least one spring for immediate use without coils around feet.
4. Approach slowly from the direction that gives the best control for wind and tide.
5. Stop the boat rather than using fenders as brakes. They protect against residual contact; they do not justify excessive speed.
6. Pass or receive the first useful line without crew jumping or placing hands between hulls.
7. Secure bow and stern, then springs, keeping the boats parallel and fenders in place.
8. Adjust fore-and-aft position to clear rigs, outlets, gates and access routes.
9. Rig any agreed outer shore or mooring lines.
10. Switch off or secure equipment that could affect the neighbouring boat, then inspect the arrangement under movement.

How do you raft boats of different size or shape?

Good rafting etiquette

• Ask permission and accept “no” without argument.
• Use clean fenders and lines; do not place a dirty fender against another owner’s topsides.
• Cross close to the mast or agreed structural route, not over windows, hatches or cockpit cushions.
• Wear clean, non-marking footwear or follow the host boat’s request.
• Keep noise, lights and onboard activity considerate.
• Do not run generators, engines or heaters where exhaust can affect neighbouring crews.
• Tell the other skipper about departure time and changes in weather or line setup.
• Help adjust the raft after a boat arrives or leaves.
• Keep keys, contact numbers and safe emergency access available as locally required.
• Leave the arrangement at least as secure and tidy as you found it.

How should a boat leave the raft?

Plan the departure before releasing any load-bearing line. Tell all affected crews, start or prepare propulsion in accordance with local rules, and identify which outer lines must be transferred. Remove only the fenders and springs that are no longer needed.

1. Confirm wind, tide and the route clear of other boats.
2. Move people and loose gear away from the separation side.
3. Transfer or re-lead shore lines so the remaining raft stays secure.
4. Release lines in an order that preserves control.
5. Use the engine and lines to move away slowly; do not push with hands or feet between hulls.
6. Recover fenders only after the risk of re-contact has passed.
7. Help the remaining boats reset their fenders, springs and access route.

Rafting checklist

• Permission from skipper, harbour or organiser
• Compatible hull size, freeboard and fittings
• Adequate large fenders plus one spare
• Bow and stern lines between boats
• Forward and aft springs
• Outer shore/mooring lines where required
• Clear mast and spreader alignment
• Clear exhausts, outlets, hatches and access routes
• Agreed crossing route and departure sequence
• Weather and tide recheck
• Post-arrival inspection after movement begins

Frequently asked questions

How many fenders do I need for rafting up?

There is no safe universal number. Cover the parallel contact zone and vulnerable bow/quarter with correctly sized fenders, then add redundancy. Larger or mismatched boats and exposed conditions need more protection.

Which boat should supply the fenders?

Both skippers should prepare adequate clean fenders. One boat may carry the primary row, but alternating or supplementary fenders can improve coverage if lines and fittings remain orderly.

Are round fenders good for rafting?

Yes, particularly at concentrated bow or quarter contact points. Cylindrical fenders are often better for continuous midships coverage, so a combination can work well.

Should the heavier boat be inside or outside?

There is no universal answer. Harbour instructions, shore access, departure order and the ability to run outer lines all matter. Avoid leaving a light inside boat to carry a heavy outside raft without an appropriate plan.

Do I need springs between rafted boats?

Yes in most alongside arrangements. Springs control relative fore-and-aft movement and reduce the tendency for fenders to be squeezed out or fittings to collide.

Can I raft a RIB against a yacht?

It may be possible with permission and suitable clean broad fendering, but protect the RIB tubes from hard fittings and confirm the hull shapes, freeboards and attachment points are compatible.

How do I stop masts and spreaders touching?

Offset the boats fore and aft so rigs do not align, then observe them under roll and wash. Do not assume deck-level fenders prevent contact aloft.

Who is responsible for shore lines in a raft?

All skippers share responsibility for a safe arrangement, subject to harbour direction. Outer boats may need lines to shore or the mooring so the inside vessel is not carrying all loads.

Technical references

Manufacturer specifications, product instructions and local berth conditions always take priority over generic guidance. Check the instructions supplied with the exact fender, buoy, holder or fitting before use.

• Polyform US — Boat Fender Guide
• Polyform US — Boat Fender Line Guide
• Polyform US — Frequently Asked Questions