How to Block a Boat Safely

Whether it’s for hull maintenance or storage, you’ll eventually need to block your boat. It’s a simple task, but requires precision to prevent damage to the boat.

There are multiple ways to safely block a boat with jack stands, but we’re sticking to a tried and true method here. Choose an area of solid level ground, then follow these tips on how to safely block a boat.

Blocking a Boat Safely

• Consult the owner’s manual for the correct positioning of keel blocks and boat stands. If you don’t have a manual, determine where the bulkheads and stringers are relative to the hull, as these points will be the most sturdy.
• Use a trailer jack to lower the front of the trailer as low as it’ll go in order to lower the bow and raise the stern.
• Build up a keel block using wood or concrete blocks, with a wood block at the top so that it’s just below the keel centerline at the transom. Use pieces of old carpet or something similar between the wood block and the hull for added protection.

• Raise the front of the trailer to make the bow rise and the stern lower onto the keel block.
• Place boat stands on either side of the hull under the chines at the points stipulated in the user manual, or at points reinforced by bulkheads or stringers. Adjust the stands to secure the hull upright and prevent it from tipping. If necessary, use pieces of plywood as bases under the boat stands to prevent them from settling into the ground or moving. 
• Lower the front of the trailer until the hull is level, then raise it again slightly and build another keel block to the forward end of the keel centerline. It’s recommended that a keel block is used for every 10’ of boat, so additional keel blocks may be required.

• Place additional boat stands on either side of the hull under the chines to provide lateral support. It’s recommended that boat stands are used for every 15’ of boat. Lower the front of the trailer so the boat is fully supported by the keel blocks and adjust the boat stands to keep the boat upright.
• With the boat no longer resting on trailer rollers, slowly and carefully pull the trailer forward. 

NOTE: It might be impossible to drive the trailer completely out because the keel block(s) toward the bow end will be obstructing the chassis cross struts and the axle(s) of the trailer, thus preventing forward movement.

• Pull the trailer forward until the cross strut or axle meets the obstructing keel block, then use a bottle jack to raise the keel slightly; build a new keel block behind the cross strut or axle; remove the keel block in front of the cross strut or axle; lower the keel onto the new block; and pull the trailer forward again. It may be necessary to repeat this several times.

For more tips on blocking a boat, check out our articles on boat blocking safety tips and why boat stands are best for storage.