Blocking, Shoring and Jack Stands
Shoring Up Your Vessel Correctly for Upland Storage and Boat Winteri
Oct 1, 2006
Most boaters haul and store their vessels on the uplands for the off winter season. Our boatyard sees a flurry of action in the fall with boaters getting ready to winterize their boats. I've witnessed a number of vessels damaged because of improper blocking and poor use of jack stands. Valdez Harbor had a severe wind event in the spring and it demonstrated what happens when a boat isn't blocked correctly. The photo used with this article shows a 28 foot charter boat that was blown off its stands. Poor shoring and blocking can cause substantial damage to boats during winter storage.
The following are some hints of how to do a better job of blocking up your boat for winter storage:
- Consider purchasing jack stands designed for use with boats. Many boaters use wooden cribbing to block up their vessels. While this will work, wood blocks are heavy, will decay, and are subject to slipping. Jack stands are quick to employ, easily adjustable, and take less room to store. Never use steel drums for cribbing.
- Use at least six jack stands (used in three pairs) on boats over 26 feet in length. Add more support for overhangs and outdrives.
- Support the keel with adequate timbers. Use substantially sized material and evenly place blocks at multiple points along the keel. Don't scrimp on the keel blocks. I have seen several boats damaged when keel blocks were installed too far a part from each other.
- The weight of the boat should rest on the keel. Your jack stands should be placed outboard as far as possible from the keel to increase stability. Jack stands should not be deflecting the surface of the hull due to high point loads. Don't put blocks under stands to make them taller, buy taller stands.
- Use jack stands in pairs, matching their locations across from each other. Tie the pairs of stands together, preferably using a steel chain designed for this purpose. Make sure each stand rests upon a solid surface. Our yard provides a plywood pad for vessel users to place under each jack stand.
- If you place a tarp or cover over your boat, ensure that water drains away from it and doesn't pool up on the vessel. Don't tie tarps off to the jack stands! Wind blowing on the tarp can pull out the stands.
Once your boat is blocked up in the yard correctly, there several things that you need to do to properly winterize it and make things easier for re-launching in the spring. Check the position and loading of the jack stands under your vessel periodically through the storage season. Stands can settle in the ground or otherwise loosen and not be adequately supporting the boat. Discuss safe shoring practices with your boat yard operator and ensure the blocking used is adequate for any of your vessel's unique characteristics.
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