Mastering The Swell Bridle: One Of The Best Kept Secrets For A Rolly Anchorage

By: Charter, Cruising Tips, Weather

As much as we sailors may work hard to take every precaution necessary to avoid it, the reality is that we, at one point or another, are all bound to experience it. “It” being the dreaded phenomenon of a “rolly” anchorage. While the most common suggestion you may get in this scenario is to pick a different anchorage, there may be times when you find yourself in a unique situation where this simple solution may not be so… well, simple.

Maybe weather and tide predictions were simply wrong, and now it’s too late to find a new anchorage. Maybe this anchorage is the only viable option while staying true to your course. Or maybe, despite warnings of its reputation for restless nights, the crew insists on staying longer at this anchorage for the opportunity to explore more, promising to remember “they’ve been warned” (words they will, most likely, regret later).


Even a seemingly serene anchorage can transform in a matter of hours – and countless seafarers have had to weather a restless night at anchor in rolly conditions.


Contents of this Article

What Is A Rolly Anchorage 

So, what is a “rolly” (pronounced “row-lee”) anchorage? Perhaps a term you may not have learned during your ASA course studies, it is one that you will immediately understand when experiencing its relentless persistence. It’s an experience that, when shared with other fellow sailors, most all can relate. And, despite perhaps employing a hint of humor when recounting their experience (having survived it), all will presumably agree that the atmosphere onboard at the time was much more somber; it was most likely a sleepless night spent eagerly awaiting the dawn and the opportunity to haul anchor and move on.

What Causes A Rolly Anchorage

Now, what causes a rolly anchorage? “Roll” occurs when a boat’s bow or stern is not aligned with the waves, causing it to “roll” side to side. In well-protected anchorages, a boat will typically face windward, taking waves head-on. However, in some cases, you may find yourself at an anchorage where certain elements (like swell wrapping around a point while the wind blows in the opposite direction) can cause your vessel to instead turn sideways to the waves or swell. The severity of the dreaded “roll” can depend on factors like wave height, wavelength, and wave frequency. In most instances, larger wave height combined with shorter wavelengths will result in greater roll. Additionally, should the timing of the waves happen to coincide with the boat’s roll period (the time it takes the boat to complete a full “roll”), you can probably expect an eventful night on board – one spent rolling back and forth in your berth desperately reaching for anything to cling onto to avoid unintentional collisions with your cabin mate, while dishes rattle noisily in cupboards and anything not securely stowed eventually reminding you of this fact. A night spent in this manner can be one of the most irritating experiences you will encounter on a sailboat and can lead to seasickness, anxiety, and a restless crew.


Thankfully, advanced technology and helpful apps like Navily can help us better predict what is in store for us at our chosen anchorages. However, we must always remain mindful that the whims of Mother Nature can defy even the most advanced forecasts.



Solution: A Swell Bridle

Oftentimes, it may be hard to gauge the severity of an anchorage’s susceptibility to this potential roll until you have already anchored. And sometimes, by then, it might be too late in the day to change location. Fortunately, understanding the cause of this “rolling” sensation can provide the ability to help mitigate it. One solution (the solution we will dig into here) is a “swell bridle.” Although it seems to have various names amongst the sailing community (“winch bridle,” “bridle rig,” etc.), the method remains consistent: tying a line to the anchor rode while also securing it to the boat’s stern. If done correctly, this technique can help alter the angle of a boat to better take the oncoming waves so that, in favorable scenarios, comfort levels on board are greatly improved.

How to Employ a Swell Bridle

First and foremost, before deploying a swell bridle, a few considerations should be made. It is important to note that in high wind scenarios (20 knots or more) this technique is not advised due to its tendency to add strain to the anchor, causing a high probability of drag. It is important to also ensure any neighboring boats are at a safe distance and that you will have ample room to swing. 

Okay, now we’re ready to break down the steps and techniques of employing your swell bridle!


FUN FACT: Some say the “Swell Bridle” technique was originally adopted in an age where vessels needed to “Point Ship” to enable the use of their cannons (which were mounted on the sides).

Step 1 – Determine The Direction You Wish to Point

Determine the swell (or dominant swell) direction. This will help determine where you want to point the bow.

Step 2 – Gather The Necessary Materials

Find a line 20+ feet longer than your boat’s length. (e.g., a 30-foot boat will need at least 50 feet of line).

Step 3 – Fasten Your Line to Your Anchor

Chances are you have already dropped anchor so, firstly, you will want to pull up some of that chain – so that you now have about 2:1 to 3:1 still remaining in the water (don’t worry, you will letting out more rode in the steps to follow).

Next, using a bowline knot, tie one end of your spare line to the end of the anchor chain that you have just pulled up (so that the chain and line combo will hit the water almost immediately when you let your chain back out in the next step). The bowline (sometimes referred to as the “King of Knots”) is preferable in this scenario not only for its ability to hold tight under heavy strain and load but also its capability to easily ‘shake loose’ once no longer under pressure. This will make hauling anchor, and removing this bridle, a stress-free experience when you decide to move on to your next destination.


REFER TO OUR ARTICLE “KNOTS MADE EASY: THE FAST BOWLINE”

Step 4 – Secure The Loose End of Your Line

Bring the loose end of your line astern, on the side you have determined will need to be facing windward, and secure it either to a back cleat or rear cockpit winch (if on a winch, only temporarily for making any necessary adjustments in the steps to come).

Step 5 – Prepare Yourself and Your Crew

If available, assign a crew member to tend to this aft line while you complete the next steps. Should you not have an available crewmember and cannot tend to the line while either operating the windlass or letting the anchor out by hand, be sure to leave some slack in the line (about 15-20 feet). Take care, however, not to leave too much! Remember, it is always easier to let more line out than it is to pull it back in.

Step 6 – Let Out Your Anchor Rode / Chain

Slowly let out rode while your crewmember coincidingly releases slack on the line from the stern (while also ensuring it remains taut on the winch or cleat). Soon, the boat should begin to turn as the wind pushes your bow over.

Step 7 – Adjust Your Vessel’s Heading

As your bow begins to change its heading, you should start to feel your boat move in a more comfortable ‘up and down’ motion (instead of ‘side to side’). Once facing more directly into the waves or swell, or once you have determined that you are at an angle to your liking, stop. (Remember – you can always adjust this angle later, either by letting more chain out or pulling some back in, if you would like to do so!) If utilizing a snubber, be sure to stop just shy of your ideal setting so that you may attach it before releasing the additional chain length needed to relieve the pressure on your windlass.

Step 8 – Lock It Off & Enjoy Your Peaceful Haven!

Once you are content with your new angle, lock off the line at the stern cleat.

Congratulations! You will now, hopefully, enjoy a more restful night’s sleep so that you may awake refreshed and ready to conquer the next day’s adventures at sea!

AD: Bulova