How to Block a Boat Keel

The weight of the keel needs blocking to support the weight of a boat when it is in storage or dry-dock. Blocking needs to be done evenly down the length of the keel, not at just one or two spots. If the keel is not properly blocked, the boat may develop a permanent hog, or sag, affecting the performance of the boat. Keel blocks are not just blocks of wood. They are blocks that are rounded on one side to permit adjustment in the height of a set of blocks.

Things You'll Need

• 10-by-10-inch keel blocks
• String level
• String line

Instructions

1. Arrange a set of three 10-by-10-inch keel blocks, two running parallel on either side of the keel with the rounded side up, and the third block spanning the other two with the rounded side down. Position one set where the front of the keel will sit, and the other set of blocks where the rear of the keel will sit.

2. Attach a string level to a string line. Stretch the string line across the top of the keel blocks, using the assistance of another person to hold the string at one end while stretching the string down the length of the blocks. Adjust the blocks until the bubble on the string level is in the center of the two marks on the site glass. Raise the blocks that by putting the two parallel blocks closer together. Lower the height by placing the parallel blocks further apart.

3. Arrange other three blocks sets as before and space them every four feet between the end blocks.

4. Set the string on top of the blocks. Ensure the string barely touches the tops of the blocks in between the end blocks. Adjust the height of each block set as necessary.

5. Set the boat on the keel blocks, but do not release the boat from the device used to set the boat down.

6. Place a jack stand under the boat's hull on the port and starboard side of the boat -- at every other keel block to stabilize the boat. Remove the device used to lower the boat.

Tips & Warnings

• Use plywood under the blocks and jack stands if the ground under the boat storage area is soft. Inspect the blocking and jack stands every few weeks to ensure that neither are settling. Adjust as necessary to avoid a permanent hog or twist in the hull.