12 tips to prepare for a hurricane
12 tips to prepare for a hurricane
“June … too soon. July … stand by. August … look out you must. September … remember. October … all over.”
As you might know, this old adage is about hurricane season, though it’s not always true. By mid-July this year we’d already had Hurricane Emily.
Hurricanes have three punches: wind, wave action and storm surge.
• Wind: Estimate wind force as: force = (velocity)2 x .004. For example, 70-knot winds can exert a force of 19.6 pounds per square foot. So for a 40-foot sailboat with an area of about 250 square feet, the sum is 4,900 pounds of force.
This formula is an oversimplification. It overstates the case because it describes forces on a flat surface oriented perpendicular to the wind, and most boats provide some streamlining. But it does give an idea of the power of wind. A point to consider is that boats will rarely face directly into the wind but, due to windage, will shear off, and that is when maximum wind force and shock-loading and chafe will occur.
A direct hit produces constant wind direction with increasing velocity. Wind direction will reverse after the eye of the storm passes.
• Wave action: Hurricanes create seas that in shallow water become steep. Shock loading of waves on ground tackle could exceed twice the force exerted by the wind.
• Storm surge: Low air pressure from a hurricane allows the sea surface to bulge up, and wind-driven waves ride on top of this bulge. The surge moves with the track of the storm, and surge heights of 10 or more feet are fairly common. The severity of the surge is compounded if it concurs with a high tide.
The time to begin preparing for a hurricane is before it is bearing down on the coastline, taking a bead at your marina or mooring. Let’s start with what you should not do.
1. Don’t take your boat to open water. The Navy moves its ships to deep water to ride out hurricanes, but those are ships — not boats — and “deep water” is 600-plus feet.
2. Don’t stay on board unless you have no choice. Your boat may be totaled in a hurricane; don’t give the storm an opportunity to total you.
3. Don’t assume your boat will be taken care of at your marina. Find out what provisions it has in the event of a hurricane. Will it provide onshore storage? How many stands will it use? Be sure to read the fine print, and make arrangements early. The marina may reserve the right to boot you out of its facilities.
4. If you’ll be seeking shelter in a hurricane hole, ideally it will be an isolated location as far upstream from open water as possible, with a couple of bends in the waterway to buffer waves and storm surge.
5. The hole should provide a lee, some shelter from the anticipated wind. Hills or bluffs are ideal.
6. The bottom should afford good holding for the several anchors you’ll need to deploy. And chafe protection is critical; normal protections won’t hack it.
7. It should be narrow enough to allow you to tie to one or both shores. You may need to find the property owner and obtain permission.
8. Well before a storm is forecast, time the passage to your shelter and allow for extra time in rough conditions. When the chips are down, get under way long before any bridges you might have to transit are locked down.
9. If you’ll be staying at a relatively exposed dock, position the boat bow out, and deploy anchors and a “cat’s cradle” of lines to help keep the boat off the dock, pilings and your neighbor. Again, chafe protection is critical.
10. Use lines one size larger than you would normally use. Too big and they won’t fit your chocks or cleats. Also, use longer lines than usual commensurate with keeping the boat from hitting anything.
11. Pray that wave action and storm surge don’t detach the dock from its pilings, and that no one around you breaks loose and is driven onto your boat.
12. Whether you’ll be securing your boat to a dock or riding the storm out in a hurricane hole, strip the boat of everything that will create windage: sails (including roller furled headsails), dodgers and Bimini tops (including support hardware), canvas enclosures.