What is a tongue jack and what size do I need for my boat trailer?

A tongue jack is an essential piece of equipment for any boat trailer. It mounts to the trailer’s tongue and provides critical functions:

• Functionality: Allows you to raise and lower the coupler, making it much easier to hitch and unhitch from the tow vehicle.
• Stability: Keeps the trailer level and secure when not connected to a vehicle.
• Safety & Convenience: Reduces strain, prevents the trailer from tipping, and makes launching, retrieving, or storing your boat much easier.

Choosing the Right Tongue Jack

When selecting a tongue jack, two main factors matter:

1. Height (Lift Range):
   • The jack must be able to extend high enough to lift the coupler above the hitch ball on your tow vehicle. This is typically listed as the “extended height” in product specs.
   • To determine the right height, measure from the ground to the bottom of the coupler when the trailer is level.
2. Weight Capacity:
   • Tongue jacks are rated by weight capacity, which must match or exceed your trailer’s tongue weight.
   • For boat trailers, tongue weight is usually 7–10% of the fully loaded trailer weight. Example: A 6,000 lb loaded trailer will have a tongue weight around 420–600 lbs. In this case, a jack rated for at least 600 lbs is required.

Most tongue jacks on the market comfortably exceed typical boat trailer tongue weight requirements, so you’ll usually have a margin of safety.