A storm anchor should be at least

• A. 50-100% as effective as the service anchor
• B. 100-125% as effective as the service anchor
• C. 125-150% as effective as the service anchor
• D. 150-200% as effective as the service anchor

Answer: (D)

In storm conditions you need a storm anchor with significantly more holding power than your service anchor to withstand stronger wind, current, and wave forces. The idea is to have a large enough margin so the anchor can still hold even if seabed conditions are less favorable or loads increase unexpectedly.

That’s why the guideline says the storm anchor should be at least 150-200% as effective as the service anchor. Providing 1.5 to 2 times the holding power gives a practical safety buffer, helping prevent dragging and keeping the vessel secure when conditions deteriorate or riding out a storm requires stronger resistance. The service anchor is for routine mooring with modest loads, so the storm anchor must offer substantially more capability.

So the choice reflecting 150-200% as effective holds the best balance of necessary strength and practical gear selection, offering sufficient margin over the service anchor.