When we travel by car to unfamiliar places we use a road map. The map shows us the roads we should follow in order to reach our destination. Sometimes there is more than one reasonable choice, and we choose whether speed or sightseeing is more important. Sometimes construction projects in progress interfere with our free choices and send us along bumpy, constricted detours. However, our travel in a car is pretty much limited to actual roads. In a car we seldom take off across fields and hillsides, although someone with a free-wheeling jeep might try it from time to time. This method of travel is the only automotive option that much resembles cruising.
When we cruise, we have maps that we call charts. They show us the boundaries of the water and its depths where the depth has been measured. Nautical charts also display a wealth of other information: shoals that may or may not be visible, the boundaries of routes and channels frequented by commercial vessels, secure areas where we are prohibited from sailing, rocks, radio towers, shipwrecks and so forth. All this information is intended to help us choose a route that will get us safely to our destination or safely allow us to view beautiful shorelines or reefs.
It is hard to say which element of information we use most, but the depth is a heavy contender for top spot. In a sailboat, we are very concerned with the depth. Our deep keel, which keeps us safe in rowdy waters at sea, limits the depths in which we can maneuver. Our boat, No Boundaries, has a keel that rides 6 feet 4 inches below the waterline. The measurement means that if we know that the water ahead of us is only 6 feet deep, we don’t want to go there. We would run aground and we might not be able to get off unassisted.
We pay a lot of attention to the depth when we are deciding where to go, how to get there and where we can anchor at the end of the day. We rely on the measured depths that are reported on our charts, but we have learned that those measurements only represent what was known at the time the measurement was taken. When we are cruising, we may discover that some of the measurements are no longer true.
As we have cruised southward, this sort of thing has happened more than once. As we approached the Alligator River Bridge, we carefully followed the chart around the markers on a convoluted path toward that bridge. Despite all our best efforts, even though the chart said we had 10 feet of water beside the red marker, we ran aground as we rounded that marker. Fortunately for us, the bottom is silty mud and Larry was able to back up and try again successfully. The measurement may have been accurate on the day somebody recorded it, but the passage of time and the movement of the silt in the river changed everything.
We grounded on something in one of the many land cuts in the ICW, too. We were in the middle of the channel. As perfectly centered as we knew how to do. Yet, we felt a thud, heard a rubbing sound and then floated free. Right in the center of the channel. We are not the first to have such an experience. There are many places in the ICW where people have run aground in the center of the channel.
They run aground other places, too. Yesterday, we passed a boat grounded right beside the channel. We arrived just as Tow Boat US arrived, and it wasn’t long before that boat was moving again behind us. We could see that the chart was a little confusing right there, and we were happy that we didn’t become equally confused.
However, we had our turn in the barrel. It was our intention to turn upriver into the St. Lucie River and anchor about a mile upstream in 9-10 feet of water. The entrance to this river is noted in all cruise guides as a shoaling nightmare, and so it is. We turned into the river channel, charted at 8 feet. That is plenty of depth. Right between the first two markers, the chart says 7 feet. That is plenty of depth. Just past those two markers, the chart reports 9 feet. That is plenty of depth. All this depth was completely lacking as we came even with Red Marker 2. We felt a gentle thud and then another, and then we stopped moving.
We were not eager to make friends with Tow Boat US, so Larry began to maneuver the boat in an attempt to get free. The bottom was very soft, but not deep enough for forward progress. At first he tried backing, then turning. The marked channel was barely wider than the length of our boat. I think we plowed a big circle there and finally floated free back in the ICW.
We had no desire to go back north in the waterway. The ICW channel we had followed to St. Lucie inlet was not very wide or very deep. It set off our 8-foot alarm numerous times. The chart problem at the river entrance did not enhance our faith in the chart overall, but we had to have faith in something. We headed south. We found ourselves in a mangrove swamp. The channel depth varied, and it was hard to find the deep part. The alarm sounded frequently. We thought we would anchor in Peck Lake, because the cruise guide said it should be deep enough, but our Raymarine charts did support that notion. Just as we reached the lake, the channel depth increased. We could see two boats anchored in the spot recommended by the cruise guide. Still, the chart did not indicate adequate depth. They could have been shoal draft boats.
Larry said, “Do you want to try it?” I said, “Do you want to explore it?” Larry said, “I think I have explored enough.” And that was it. We continued. The next opportunity for an anchorage was on the west side of Hobe Sound. There are three little spots just off the channel where depths from 7 to 12 feet are reported. When we arrived at the marker for the first one, there were four boats in the area already. There was nobody in sight at the second one. We cruised in, carefully watching the depth finder. The chart said 9 feet, and the depthfinder reported 10 or 11. We threw the anchor out, waited to see if it bit, and we were home. Safe at last.
There is a note in one of the cruising guides that many people opt to run outside from Fort Pierce to Lake Worth due to the shoaling problem around the St. Lucie inlet. We made it, and we are not much the worse for wear, but I think we have seen all we need to see on that path. We know exactly where the bottom is, and we don’t need to find it again.
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