Tropical anchoring

The image of the idyllic tropical anchorage is a powerful one. Peruse most charter company adds and you’ll be wooed by images of perfect anchorages where the water is warm, the sun always shines, and one’s major concern is keeping the beer cold. Regrettably, there’s usually more to it than that. Anchoring in tropical waters differs in several important respects from anchoring in temperate areas, and failure to heed these differences and prepare for them has caused many sailors and their boats to come to grief.

The most obvious and important difference is the presence of coral reefs. Reefs can provide both beautiful and wonderfully sheltered anchorages, but can also prove treacherous and unforgiving if the anchor drags or conditions deteriorate. Further complication is added in many tropical countries where poor charts and an absence of markers make reliance on visual navigation a necessity. In addition, remote tropical areaswhere marinas and, in fact, services of any kind, are few and far betweencall for a high degree of self reliance and require that the voyaging sailor be ready to cope with just about anything in the way of weather and anchorages.

That’s not to say that anchoring in the tropics is horribly complex or that it requires radically different ground tackle, though some additions to the temperate water equipment may be in order. Most important is an awareness of the tropical environment; given that, you can plan ahead, making informed decisions on where to anchor and what gear to utilize.

Making a match

We’ve met many voyagers in the tropics who seem to think that the answer to good holding is a heavy anchor. While there is no doubt that choosing an anchor of suitable weight is important, it’s not true that extra weight ensures good holding. What’s often overlooked is the importance of matching the anchor to the bottom. Despite what some manufacturers might claim, no anchor is ideal in all conditions. An anchor that holds your boat securely in gale-force winds on a sand bottom may be all but useless if you’re anchoring in broken coral or in the soft mud that is common of mangrove-lined inlets.

Bottom types in the tropics include coral, rock, sand, and mud, and combinations of these. Sand and mud provide the best holding and should be chosen whenever possible. If you’re using the proper gear and the anchor is properly dug in, you’ll be unlikely to drag unless conditions take a truly dramatic turn for the worse. Anchoring in rock and coral is much less certain. Your boat may seem to be securely anchored only to begin dragging with a slight shift in wind direction. Conversely, your anchor is much more likely to become hopelessly stuck in a rock or coral bottom, and if the anchorage is deep retrieval may be difficult or impossible. Finally, anchoring in live coral can be extremely destructive: hundreds of years of coral growth can be wiped out in a single night by the action of your anchor and chain.

Choosing your anchors

What anchors should you carry in the tropics? Plow anchors (including the venerable CQR, Bruce, and Delta) are deservedly popular among voyagers, as they are effective all-around anchors, good in mud and sand. We have found the CQR to be poor at holding in rocky and coral bottoms; our Bruce wedges itself into crevices more easily, and so we tend to favor it in tropical areas. One-piece plows stow well on bow rollers but otherwise present some serious stowage challenges. Any plow is likely to have trouble getting to the bottom if there is a lot of weed or seagrass.

Though rarely seen on boats these days, the fisherman anchor is probably the best at penetrating weed, and it is also a good choice for rocky and coral bottoms. Fisherman anchors present an even bigger stowage problem than plows, and for that reason alone few boats are likely to choose a fisherman as a main anchor. They’re excellent as a back-up anchor, however, and can be deployed if conditions are such that one’s main anchor refuses to hold. Stowage can be eased by choosing a three-piece version; our Luke anchor stows handily in the bilge, out of the way, with its weight contributing to the boat’s stability.

Pivoting fluke anchors such as the Danforth and Fortress are very effective in clean sand and hard mud bottoms, but may drag easily in very fine mud and are even worse than plows in coping with weed and seagrass. We’ve found them to be essentially useless in rock and reef. Many voyagers use them as stern anchors, and they stow easily on the stern rail.

A “pick” or grapnel is a good choice for very rocky or coral bottoms for two main reasons: their low cost makes jettisoning the anchor more acceptable should it become hopelessly stuck, and they do less damage to coral than other types of anchors. A pick, however, belongs in the class of “lunch hooks”; they’re good for a brief stop, with crew staying on board, or at most snorkeling nearby.

Carry more than one

The best way to ensure that you can anchor securely in a variety of bottom types is to carry more than one anchor. How many depends on the size of your boat and how far you’ll be sailing. Long-distance voyagers should carry at least two different types of working anchors and a kedge. This ensures a remaining working anchor should one be lost and gives a greater choice of anchors to use on different bottoms.

We’ve gone one further and carry three working anchors and a kedge. The anchors are all of different types: a fisherman, Bruce, CQR, and a Danforth kedge, allowing us to select an anchor for almost any bottom. Being of similar size and strength, the rodes and shackles for each are interchangeable. All the anchors are easily handled, be it in the water, on deck, or in the dinghy. We don’t carry a storm anchor due to the stowage and handling problems that come with a 70- or 80-lb hunk of metal. Instead, we rely on using our four anchors in combination; set properly, they’ll deliver incredible holding power and can be set to hold our boat securely even with wind that clocks around quickly from different directions (as might happen during a hurricane). Finally, by placing reliance on separate anchors and rodes, we have invested in considerable “chafe insurance,” chafing of anchor rodes being a major cause of problems during hurricanes and severe storms.

Anchor rode

Most tropical sailors select chain for the rode on their primary anchor, and many carry enough chain for a second and third anchor as well. Chain is a wise choice due to the high risk of abrading line on coral. In addition, by using chain you reduce the amount of rode needed by half, as you can anchor on chain using only half of the 7:1 scope needed when anchoring on line. The down side of chain is the weight; some tropical anchorages are deep75 feet and moreand this can mean carrying and using 250 or 300 feet of chain for just one rode. The 5/16-inch chain we use weighs about 1.2lb/foot. Two rodes of 300 feet weigh in at more than 700 lbs, not to mention the anchors themselves. How do you keep your boat from sinking under all the weight?

The only way is by reducing the amount of chain you carry. We’ve come up with a compromise solution, based on the conflicting needs of good abrasion resistance, reasonable weight, and the ability to anchor in deep water. The primary rode consists of 160 feet of chain spliced to 330 feet of line. In anchorages that are 45 feet deep or less (and that’s most of the time), we anchor on all chain. If really bad weather threatens, or the water is deeper, we pay out all of the chain as well as some line. How much line? In light conditions we use a length of line equal to the water depth, thus keeping the line clear of the bottom. When the wind pipes up we pay out additional scope, to equal about 5:1.

If the winds are light and the anchorage 70 feet deep, we’ll pay out all our chain and some 70 feet of line as well. If the wind gusts up we might pay out another 120 feet of line, for a combined length of line and chain of 350 feet and a scope of 5:1. This still leaves 140 feet of line in the anchor locker should things get really nasty; with all 490 feet of chain and line out the scope would be 7:1. Having a splice between chain and line makes paying out or taking up rode a very simple operation.

Whether you decide to rely on all chain or a chain and line combination for your primary rode, don’t stop there but make sure you have a second anchor rode that is ready to go with little or no preparation. If you can carry the weight, all chain is fine; alternatively you can set up the rode for the second working anchor in the fashion we describe above. We’ve opted for further weight savings and use a short length of chain (about 30 feet) spliced to 250 feet of line. We carry several additional short lengths of chain that can be shackled to this or used in conjunction with yet more line for our other anchors. Using a second anchor rode of almost all line hasn’t proven a problem after five years in the tropics, and the weight (and cost) savings are considerable.

Additional gear

Anchor gear doesn’t stop with anchor and rode, and the following additional items should not be thought of as optional. If you’ve voyaged in temperate waters your boat should already be properly set up with a secure place to make fast the rode, be it cleats, bitts, or a samson post. If not, choose whichever fits your foredeck, and make sure it’s stout and securely through-bolted. The bitter end of the rode should be equally well secured, somewhere in the chain locker, and preferably by a heavy lashing (which can be cut in an emergency).

Anchor rodes have a habit of jumping out of open chocks and rollers and then damaging other gear or chafing severely in the case of line. To prevent this, fit a bail to the anchor roller, or use closed chocks if you lack a roller. While you’re at it, check to see that you have some lengths of plastic tubing or other material to guard against chafe.

You should carry an anchor snubber and use it whenever you anchor using chain. The snubber eases the shock loads on the chain (and the boat), and these can be very high when anchored in rough conditions, especially if your chain has wrapped itself around a coral head, which then reduces scope. The snubber is simply a nylon line (equal in size to your anchor line) secured to the chain by means of a rolling hitch or chain hook. We’ve sometimes seen voyagers using very short snubbers, but these are of little use as they have minimal stretch. Consider 20 feet a minimum. Ours is now 40 feet. Previously, we used a shorter snubber that broke when waves broke over our bow while anchored in the lee of Minerva Reef (a mid-ocean reef located between Tonga and New Zealand) in strong winds.

A small buoyor a fenderand some 100 feet of 1/4-inch line is your final piece of essential gear. This is a trip line; attached to the anchor’s crown, it can be used to help free the anchor should it become jammed in rocks or coral. Leave it in the locker if you’re sure the bottom is clean mud or sand, but if there’s a chance it’s foul, rig the trip line.

Tropical anchorages

There are an infinite variety of tropical anchorages, but here we’ll focus on the three major types: reef anchorages, mangrove anchorages, and river anchorages.

Reef anchorages are the ones you dream about during those long northern winters; they’ve got the great sandy beaches, swaying palm trees, and beautiful corals and fish. They’re also potentially the most treacherous.

Reefs come in different forms, and each presents its own anchoring challenges. Lagoons can form ideal anchorages in reasonable weather, due to the protection they afford from sea and swell. But they require special care when dropping the hook, as even seemingly open and clear lagoons often contain patch reefs and isolated coral heads. The bottom within a lagoon can vary from coral rubble to sand and occasionally mud; sand is naturally preferred, with mud a second best. Patch reefs that lack a lagoon often provide a suitable anchorage in their lee, but the same concern with coral heads and small patches applies. Fringing reefs can provide a suitable anchorage, but only if they have a relatively gentle slope; steeply sloping reefs will usually require the use of two anchors, or an anchor and a line ashore. Keeping a careful eye (and ear) on the weather is good practice when anchored in any reef environment, but it is especially important when off patch and fringing reefs, as a wind shift can place you on a very dangerous lee shore.

The threat of bad weather normally has tropical sailors seeking more sheltered anchorages than what most reef environments are able to provide. More often than not this means a bay or inlet that is lined by mangrove trees. The mud bottoms typical of mangrove areas are often a welcome change for the sailor who has been coping with coral-strewn lagoons. Care is needed, however, as coral is sometimes found at the edge of a mangrove-lined inlet, and the mud bottom can make this coral very difficult to see. Occasionally, one will also encounter coral patches within a mangrove anchorage. If in doubt, send someone aloft to determine if a fringing or patch reef is present, and keep a close eye on the depthsounder.

Tropical rivers can also provide good anchorage, and even tidal rivers will be free of coral due to the presence of fresh water. Slow-moving rivers should present little challenge when anchoring, but when currents in tidal rivers reach several knots or more special care should be taken. The direction of the current flow in tidal rivers changes several times per day, and the anchor can easily foul as a result. The solution is to use two anchors, with both rodes led to the bow. Don’t make the mistake of using a bow and stern anchor in a river. If one anchor drags, the resultant force on the anchor rode escalates rapidly as the boat moves sideways to the current. We lost an anchor, and almost suffered serious injury, while anchored like this in Australia. Rivers and creeks generally offer the best shelter in a cyclone or really severe storm conditions, though flooding can be a problem.

Evaluating an anchorage

Our first reconnaissance of an anchorage usually takes place long before we arriveoften before we set sail. A detailed chart is the best aid, and safety is the primary concern. Consider if the potential anchorage is exposed from a particular direction, and check the forecast, the sky, and the barometer to determine if adverse weather is likely. With a lagoon or other reef anchorage, check to see if you’ll be able to leave the anchorage at night should a storm hit. We’ve anchored in many reef situations when a night departure was impossible, but we did so only when the weather forecast was favorable or the anchorage very sheltered and the holding good.

The next evaluation should take place as you approach or enter the anchorage. Check to see if there is room for your boat to swing without hitting rocks, coral, or other boats. This may require that you make some circles with your boat while keeping an eye on the depth sounder.

Once an anchorage passes the safety test it’s time to search out a reasonable depth and drop the hook. In river anchorages you may want to select an area of least current, while in mangrove inlets the main concern is to ensure the boat will be free of any fringing coral. In coral lagoons and other reef anchorages you should endeavor to drop the hook in sand, away from coral, whenever possible. To zero in on the clearing, ensure that the boat is stopped before you let the hook go. At times you may want to send a crewmember over the side with mask and snorkel to check the condition of the bottom. On deck, it’s quite easy to mistake a dark patch of seagrass for coral, and by doing so you may pass up what would have been a superb anchorage.

Avoiding coral wraps

It’s not uncommon, especially when anchoring in lagoons, for the anchor chain to become wrapped around coral heads and outcrops. This is destructive of the reef, hard on the chain and its galvanizing, and potentially dangerous as it may prevent you from retrieving the anchor quickly should that become necessary. The simplest way to avoid it is to find a coral-free area large enough to allow you to swing freely without the chain hitting any coral. In good weather you can minimize the area you need by using less rode. We’ve often anchored (using our Bruce anchor and chain) with a scope of 2:1 in areas where the anchorage is protected and the winds light. Use this technique only if you’ll be staying on board or if you’ll be in the anchorage where you can monitor the conditions. If the wind comes up and you’re ashore for the day, you could easily lose your boat. For situations when you need the limited swing that short scoping produces, but also the security that comes with proper scope, use a weight that is lowered down the rode.

Such weights go by various namessentinel and angel are twoand come in different shapes and sizes; typically, they’re attached to the rode by means of a large shackle. A retrieving line should be used so that the sentinel can be retrieved before weighing anchor. Sentinels are commercially available, but any convenient weight of some 20 or 25 lbs will do. A few dive weights strapped together would do a fine job, or you could make use of your stern anchor. With the sentinel in place, swing will be reduced to a minimum while security is actually increased, as the pull on the anchor is now parallel to the bottom.

Retrieving the anchor

Unfortunately, what goes down doesn’t always come up. Anchors do get stuck, particularly in rocky or coral bottoms. This is when a trip line comes into its own; hopefully you had the foresight to rig one. Slack off the rode a bit, haul away on the trip line, and the anchor should come free. If this fails, or if you didn’t use one, then some vigorous maneuveringforward, astern, and to port and starboardshould work the anchor loose. If it doesn’t, it’s probably time to get in the water.

Don your snorkel gear and head down to have a look at how the anchor is jammed. This is often all you need to do: having seen the crevice or coral head that has your anchor captive, you can return to the boat knowing the direction in which to head to free the anchor. At times, though, you’ll find the anchor wedged so securely that you have to free it by hand. Unless you’re anchored in shallow watersay less than 20 feetthis is likely to be a challenging operation. How well you fare depends a lot on the water depth and your diving abilities; if you have problems free diving you might want to consider packing along a small scuba tank for this kind of situation. Don’t give up too quickly, and if necessary try to get some help. There may be other voyagers nearby with dive gear, and some of the islanders we’ve met in the Pacific are fantastic free divers, able to dive down to depths of 50 feet or more for relatively long periods of time!

But the best solution to this problem is to avoid deep anchorages with rocky or coral bottoms; if you must anchor in such a situation, use a coral pick. Failing that, drop the anchor you’re least attached to, and consider using a short length of chain with line attached, so as to avoid losing a long length of costly chain.

Mark Smaalders, who has sailed in the tropics for the last 12 years, logging some 30,000 miles through the Pacific and Indonesia, is currently in Australia, preparing his 35-foot wooden sloop Nomad for a trip to New Caledonia.

By Ocean Navigator