Last fall, on the last day of our passage from Houston to Grand Cayman we realized that we would be arriving at the island late in the afternoon and would have to anchor for the evening in order to clear in with Customs and Immigration the next morning. And so with chart and cruising guide at hand I began to look for a good place to anchor. What I was looking for was somewhere that would be easy to enter with no obstructions such as rocks or wrecks or reefs to circumvent, somewhere where we would be protected from the swells and have calm water and a spot where we could reasonably expect the anchor to set well.
Given that in the Caribbean the wind comes mainly from the East, the West side of most of the islands is usually protected from the seas as the wind is blowing off the land and on Grand Cayman that is where the famous 7-mile beach is located so I was off on the right track. But as well as avoiding an onshore wind, I wanted to be protected from any swells that may curl around headlands and enter the bay from a different direction to the prevailing wind. With this in mind I chose a spot in West Bay near the north end of the beach where the headland sticks out to the west creating a small protected bay. Here there was only one obstruction, a rock awash close to the shore but by lining up the light on the north end of the island with the Church steeple I could see from the chart that, so long as I stayed to the East of that line I would easily avoid the rock and I could close the shore until I was in water shallow enough to anchor.
By mid afternoon it was clear that our arrival off the coast would occur close to dusk and, sure enough, we saw Grand Cayman growing larger as we watched the sun set behind us and by the time we were within a mile or so of the shore it was really dark – not even a moon to help us. And to add to the difficulty the light shown on the Chart as being located at the highest point at West Bay was clearly not lit. And in the dark it was too much to expect to see the church steeple. However we had GPS on board and with the radar interface it was possible for us to see on the cockpit mounted radar screen the outline of the bay along with our GPS position and the waypoint I had chosen from the chart where I would like to drop the anchor.
Slowly we entered the bay and then, still in deep water, we lowered the mainsail and prepared to anchor. As the anchor chain was not marked, we pulled up on deck the 50 feet of chain that I had estimated we would need and we then cleated off the chain. Once this was done we untied the anchor, released the chain dog and lowered it over the bow roller and then cleated it temporarily so that it was swinging from the bow.
Back at the helm I started motoring directly toward the shore watching the depth sounder and with the crew on deck watching for crab pots or other unexpected obstacles. And just as the houses on the beach seemed to be getting too close and my nerve was about to fail me, we got down to 15 feet on the depth sounder and I brought us to a stop with a short burst of reverse. We lowered the anchor, turned off the engine and poured ourselves a drink. It was the end of a fast and exiting passage and we were anchored off the beach of a tropical paradise!
For several days I had been looking forward to the moment when we would be anchored in calm water and I could relax and have a full uninterrupted nights sleep but it was not to be. The anchorage was fine expect for one small thing: a light swell was entering the area and, all night, hitting the boat on the beam resulting in a rhythmic rolling that was not as pleasant as it sounds. But I still slept reasonably well and in the morning we were able to enjoy breakfast anchored 100 yards off a palm tree’d shore and watch the fish darting among the occasional coral heads which dotted the sandy bottom where we had anchored.
Sometime this spring the dredging will begin along the Houston Ship Channel and some of the spoil from the deepening and widening is going to be used to create artificial islands in the bay that will hopefully provide us with some new destinations and a few good anchorages. And in anticipation, here are some pointers to the way I choose to anchor.
Choosing an anchorage
When you are looking for the ideal place to anchor you need to consider the wind, weather forecast and local conditions, currents, other traffic and, of course, the type of bottom where you will drop your anchor.
For the anchorage to be in calm water (you would only choose otherwise in an emergency) you need the wind to come off the land so that, anchored close to the shore, there is no build up of swells. But not only do you need it to be flat water when you anchor, you need to make sure that it will remain so while you are there. Should a strong onshore wind build up while you are at anchor it will mean that you are close to a lee shore where you will inevitably end up if you anchor drags and that escape will be difficult going directly into the wind and seas as you attempt to pull up the anchor. A good anchorage will be protected from many directions of wind and certainly from the prevailing wind direction and from any directions that the wind may come from during your anticipated length of stay.
Consider also any currents that may flow through the anchorage area. I recall an anchorage on the Intra-coastal Waterway on the East Coast of Florida where we were protected from all possible wind directions but where the strong currents and the prevailing wind combined to make the boat pirouette around the anchor until it eventually pulled out of the bottom and we had to reset it in the dark and then remain on anchor watch until the tide had turned.
Other traffic is another consideration as among the other undesirable features of the anchorage in Galveston close to the Yacht Basin, this is one. Commercial traffic going up and down the channel and shrimp boats fishing in the anchorage areas create wakes which will result in your boat rolling uncomfortably.
But of all these considerations, the type of bottom is the most important as you rely upon this for your anchor to truly set and hold the boat. Good bottoms are mud and sand but you will experience poor holding among stones or weed. Rocky bottoms can be very secure once your anchor catches in a crevice but it then may be difficult to extricate. And coral, should you be reckless or care-less enough of the environment to choose this type of bottom, will provide good holding though it will chafe through a nylon rode in minutes.
Where exactly to drop the anchor
Once you have selected the anchorage area, your next decision is where exactly to anchor. In an uncrowded or empty anchorage you can choose a position close to the shore which will be convenient to you, where the depth is shallow enough to require little anchor rode and where the bottom provides good holding. Choose a spot where you will be protected from as many wind directions as possible and one that will give you an easy escape you if you need it.
In a crowded anchorage area it is not easy to choose a spot where you can anchor safely without risking your boat hitting another when the wind shifts. However, if you find an area where the already anchored boats are using the same type of rode as you do (nylon rope or chain) then I have found that often a good place to actually drop the anchor is as close to the stern of another boat as possible. Approach slowly as it will be pretty intimidating to the other boat as you approach their stern from down wind with a menacing anchor hanging from the bow. And as you get as close as you dare to their stern, bring the boat to a stop and let the anchor down. Once you have paid out the rode and settled down on the anchor you should find yourself a sufficient distance from the other boats and, with you all swinging in roughly the same way and at the same distance from your anchors the chances of swinging into another boat are minimized.
How much anchor rode
An anchor works by burying itself in the sea bottom but it is designed only to do so when the full on it is horizontal as this way, by shortening the anchor rode and pulling almost vertically you will be able to recapture your anchor. Understanding that a horizontal pull helps to set the anchor and that a vertical pull will lift it out from the bottom helps to appreciate why you need to use a long length of rode with an anchor. It also explains why even with a nylon rode, a short length of chain is attached first as the weight of the chain helps to hold the anchor rode on the bottom.
When using a nylon rode you should have a minimum of 10 – 20 feet of chain attached from anchor to rode. Not only will it help set the anchor, it will give you some protection against chafe by sharp rocks or other objects on the sea bottom.
The standard recommended amount of nylon rode to use is between 5 and 7 times the depth of water where you are anchored. Thus in 15 feet of water you will need somewhere between 75 and 100 feet of rode. Anchored for lunch you can choose the minimum; anchored for a week choose the longer scope so long as it will not cause you to swing into other boats in the anchorage.
If your anchor rode is all-chain then you need less scope to give you adequate holding as the weight of the chain helps to keep the pull horizontal. Between 3 and 5 times the depth of water is normal sufficient.
Because you need to know how much anchor rode you have paid out into the water, it is a good idea to mark the rode every 10 feet or so. You can do this in the traditional way by threading thin strips of leather into the lay of the rope or more easily by buying a set of plastic markers made especially for this purpose. When using an all-chain rode you can paint a few links every 10 feet with the number of painted links indicating the length.
To set or not to set
Once your anchor is on the bottom and sufficient rode paid out it is sometimes recommended that you engage reverse gear and motor backwards to set your anchor. I rarely do so at this time. For your anchor to work it has to bury itself in the sea bottom and it will do so gradually because of its weight and the gentle pull on it caused by the wind on your boat. When you decide to motor backwards as soon as the anchor is on the bottom you are more likely to cause it to skip across the surface then to bury itself. Letting the anchor set itself usually works best but once you have allowed time for this you may want to check that it has set before you leave the boat to go ashore!
Checking for a dragging anchor
Once your anchor has had time to set itself, start the engine and put in slow reverse which will take up the slack on your anchor rode. Once the rode is tight, increase the engine speed and watch your anchor rode. You will find that it surges a little, stretching as the engine pulls on it and then slackening a little as the springiness of the rode exerts itself. This is normal; a steady pull on the rode is often an indication of an anchor dragging across the bottom.
Other signs of a dragging anchor are a rumbling sound from the rode; the bow of the boat blowing off the wind so that it appears your boat is more sideways to the wind than others around you; and a rapidly approaching shore or boat that was some distance behind you! Don’t panic. Start the engine and gently motor forward while recovering the rode and anchor so that you can try again.
Before you leave a boat at anchor, set the anchor and take bearings around you. I usually try and line up my eye with the mast and a building ashore and then watch this for a few minutes. As the boat swings on the anchor or wind gusts stretch the rode this transit will change. Watch for the maximum point and then make sure that whatever the swing or gust it is not exceeded.
Before attempting to anchor check that
- The anchor rode is attached to the anchor and that all shackles are tight and secure
- The end of the anchor rode is firmly attached to the boat
- The rode is marked along its length, or failing this, you have the correct length of rode already out on deck
- The place you have chosen to anchor has good holding and is otherwise safe
Like all skills, anchoring is easy when you know how but can be difficult and confusing to start with. Gain some experience with your anchor and develop your skill and confidence before you rely on it and leave the boat to go ashore or turn in for a full nights rest. And remember that, like everything else, there is more to learn. Once you have learned to anchor with one anchor you can learn how to use two in different ways – perhaps I will make that the topic for a future Seamanship column.