How your boat is "blocked" once it’s off the Travelift or the trailer is critical. While a boat can be blocked properly on cement blocks, jack stands (aka "boat stands" or "poppets") are the pro’s choice. Some boat manufacturers recommend positioning for blocks and jack stands, so check the owner’s manual or with the builder. Generally, keel blocks should be positioned under internal bulkheads to avoid stressing the boat. Improper blocking can lead to gelcoat stress cracks, damaged stringers, misaligned engines and other problems. Check for proper blocking under your boat or that new one you’re considering.