Upon This Bank and Shoal of Time

Careening your boat on a bank that dries out at low tide may be your only option when cruising in the back of beyond

February 4, 2002


Tosca leans against sandbags that keep her propped at a habitable angle Theresa Nicholson

After a two-year cruise through Micronesia and eastern Indonesia, our 32-foot, double-ended wooden ketch, Tosca, arrived in Bali’s Benoa Harbor in dire need of new bottom paint. Bali lacks a haulout facility for cruising yachts, and the thought of scrubbing the bottom all the way to Thailand wasn’t exactly my idea of fun in the sun. My husband, Darrell, and I began monitoring the tidal changes on the sand flat just off Tosca’s bow, and a plan began to form. As the new moon approached, we decided to careen Tosca on the flat and apply a new coat of bottom paint.

With a bit of planning, careening a sailboat on a sand flat can provide a cost-efficient and convenient way to add bottom paint and execute minor repairs in harbors where haulout facilities aren’t available. So for cruisers contemplating exploring off the beaten track, knowing how to safely careen a boat is a valuable skill. Some boats are more suitable for careening than others, and if the procedure isn’t done properly, it can lead to more serious challenges than painting the bottom.

Also, in U.S. waters, careening and painting is frowned upon, and in some areas, it’s illegal. Plus, paint manufacturers probably cringe at the prospect because careening seldom allows sufficient drying time to guarantee good adhesion. But in the real world, you can’t always go by the book.


Finding a Flat
You’ll need to find a sand flat that dries on the falling tide in an area where the tidal range is greater than the depth of your keel. Tosca draws 6 feet, and we planned our four-day careening around a spring tide with maximum tidal ranges between 6.3 and 8.3 feet. After choosing an area that offers sufficient tidal range, check the surface of the flat. We walked the flat at low tide and looked for a relatively level, hard, sandy patch that was free of rocks. We found a suitable spot to careen near the flat’s edge and marked it with two plastic bottles anchored with rocks.

At high tide, we checked the markers and noted again that the depth was just over 6 feet. We also took bearings off a few prominent trees on shore to use when we approached the flat. Next, we compared our physical survey of the area with our study of the local tide tables. We wanted to ensure that what was recorded in the tables corresponded to what we were actually observing on the flat.

We planned to spend four days on the sand flat–two days working on the port side and two on the starboard–and we wanted to leave the flat on the day with the highest tide. Turning to the tide tables, we noted the extreme low tides and tidal ranges near the time of the new moon. On the calendar, we marked the day with the greatest tidal range and counted back four days to find our starting date.


We also checked the times of the harbor’s daily high and low tides to see which ones fell at feasible times. On our first day, high tide was at 7:36 a.m., low at 2:13 p.m.; this was ideal. We were able to take Tosca on the flat at 7 a.m. and get a coat of paint on one side by 1:30 p.m. If our first low tide had fallen at 7 a.m., we’d have had to go on the flat in the wee hours and prep and paint the boat at 5:30 in the morning.

Time and Tide
Collect and organize all of your supplies before going on the flat. These will include bottom paint, sandpaper, brushes, scrapers, thinner, rollers, masking tape to mark the waterline, scrungie pads for scrubbing, rags, gloves, garbage bags, paint-stirring sticks, a drop cloth, buckets, and paint trays. Once the project starts, you’ll be working against the clock, so scope out nearby sources of such emergency supplies as paint and thinner.

Before careening, shop for quick-drying paints. We used copper-based International paint, which is readily available in most parts of the world. Also, open your bottom-paint can well in advance to see how much mixing will be required. You don’t want to discover at low tide, when time truly is of the essence, that your antifouling still needs an hour of mixing.


Before going on the flat, balance the boat and clear the decks as much as possible. Have an ample supply of fresh water on hand to rinse the hull after sanding. Make plans for an alternate sink and head to be used while working on the flat. Because opening a faucet is such a reflex action, set up your drains in a way that won’t interfere with a fresh coat of paint. We inserted an 8-foot length of vinyl tubing into the outside of the through-hull, just in case we forgot we were careened on a flat. Secure everything belowdecks for the extreme heel.

To make life aboard more tolerable during the ordeal, we planned to careen Tosca against a wall of sandbags rather than lay her all the way over on the flat. The day before careening, we took 30 flour sacks out to the flat and filled them with sand. We gave the boat’s bottom a good scrub, and to hold Tosca in position, we flaked out the three anchor lines we intended to use in addition to our chain anchor rode.

Going In
This is when you really get to know your tide chart. Our tables listed the daily range of the tide and the two high tides and two low tides that occur in Benoa Harbor every 24 hours. Using the “Height of Tide at Any Time” tables in Reed’s Nautical Companion (1998; Thomas Reed Publications Inc.) or on Integrated Publishing’s website ( weather3/6b-16.htm), we were able to estimate the flat’s depth at regular intervals. Then we crafted a table that listed the exact times of the highs and lows on the four days we planned to be on the flat and the periods when the flat would be dry.


We also tried to pinpoint the times each day that Tosca would be aground and when she’d refloat. Looking at our chart listings for the first day and working backward, we determined that if the low tide was at 2:13 p.m., we should finish painting by 1:30 p.m. to allow the paint at least an hour to dry. We hoped the depth would be low enough to start sanding by 10:30 a.m., giving us a couple of hours to prep the hull.

At 7 on the first morning, roughly half an hour before the 7:36 high, with our hearts in our throats we drove Tosca aground, laying out a stern anchor to starboard as we made the approach. I then lowered our bow anchor and chain rode into the dinghy, and Darrell set it about 150 feet off the starboard bow. Next, we set a stern anchor to port. Then we rowed a fourth anchor off our port bow.

By 10:15, the water on the flat was shallow enough for us to stand. Tucking the sand bags along the port hull and building a makeshift wall against which Tosca could lean took almost an hour. Movable ballast on deck–water jugs, jerricans of fuel, and the like–helped us tip Tosca to starboard, and as the tide fell, she settled against the sandbags.

We’d determined from the tide tables that we had 7.9 feet above mean low water on the 7:36 a.m. high and 1.6 feet above mean low water at 2:13 in the afternoon. The tide didn’t fall low enough our first day to completely expose the keel. But on Day Two, the tide fell low enough and fast enough for us to get an additional two coats of paint on the starboard side, including the inch along the keel we were unable to cover the day before. Days Three and Four had even greater tidal ranges, and we were easily able to get several coats of paint on the port side.

The trick is planning the haulout around tides that fall low enough the first day to paint and rise high enough the last day for the boat to get off the flat. Make sure you know how many feet above mean low water you’ll have at high tide on the day you plan to go off the flat.

Sanding and Painting
On Day One, our low tide bottomed out at 2:13 p.m., and we hoped to get the first coat of paint on the hull by 1:13 to give us that hour of drying time. While the water wasn’t low enough to paint until 12:40, we still tried to organize ourselves around that timetable. Likewise, we planned to start sanding at 9:40 a.m., but the water was still too deep then. Although our water-level calculations weren’t perfectly accurate, they helped us plan for each stage.

We spent as much time as possible prepping the hull on Day One, so we had time for only one coat on the starboard side. On Day Two, because we only needed to sand and rinse the salt residue off the new paint and because the tidal-range increase gave us more time to work, we were able to apply second and third coats to the starboard side. On days Three and Four, we followed a similar pattern on the port side. The tidal range increased each day, and by Day Four, the sand flat was completely dry two hours before and after dead-low tide.

Between Tides
To avoid the wakes of vessels, we chose an area with minimal traffic, but as the tide ebbed that first day, we still bounced on the flat. We kept the movable ballast on deck, along the starboard rail, and Tosca’s hull eventually rested against the wall of sandbags while her keel settled into the sand flat.

The second high tide of the day that week was lower than the first. We went aground the first day on a high tide that was 6.3 feet above mean low water. The second high that day was only 5 feet above mean low water, so we stayed grounded. The next morning, we floated off on a 7.2-foot flood tide and had to reposition ourselves against the sandbags.

We stayed put on the second day’s second high (5.9 feet) and floated off on the morning of Day Three with a 7.9-foot tide. We moved the sandbags to the port side rather than move the boat on the third day. Moving the boat would’ve meant working along an edge that shoaled off at a steeper angle, leaving part of the keel underwater longer. On our final day, we had a morning high of 8.2 feet, and although the evening high was lower, at 7 feet, we still had enough water under the keel to back off the flat.

Getting Off
Through the careening, we had port and starboard anchors set in shallower water on the flat and stern anchors set on both sides about 100 feet off the stern in deeper water. Once the job was complete, we no longer needed all four anchors to keep us in position. While we were still high and dry, we retrieved the chain anchor off the starboard bow and shifted the port bow anchor, on rope rode, so it lay slightly off to starboard.

When we had enough water under the keel, we backed Tosca off the flat by pulling on the stern line and letting the bow anchor rode, followed by the secondary stern anchor, free on floats. We walked the port stern anchor to the bow, which turned us into the wind and left us floating in deep water. The next day, we retrieved the anchors and, at low tide, emptied our sandbags.

Having careened Tosca for fresh bottom paint, we know we can do the same for emergency repairs. Hot, windy weather, the perfect flat, and a well-thought-out game plan helped us apply three coats of paint, and we didn’t have to scrub the bottom all the way to Thailand. Now, two years later, we’re just about due for a new coat.

Theresa Nicholson and her husband,
Darrell, live in Portsmouth, Rhode Island. Tosca lies in Malaysia.


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