Trailer lock for boat trailers and caravans
A trailer lock is a mechanical lock that secures a boat trailer against theft or being towed away. The two most common types are the hitch lock, which blocks the ball coupling, and the wheel clamp, which immobilises a wheel so the trailer cannot be moved. We stock trailer locks from DoubleLock, HIBO and own brand, ranging from affordable entry-level to heavy SCM-certified security.
Hitch lock or wheel clamp?
| Type | How it works | Best for |
|---|---|---|
| Hitch lock | Blocks the ball coupling on the drawbar | All trailers with standard ball coupling |
| Hitch lock with ball | Fully covers the coupling, highly visible | Deterrence + mechanical blocking |
| Wheel clamp | Clamps around the wheel, trailer cannot move | Trailers with 13 to 15 inch wheels |
A hitch lock is the quickest to fit and works on any trailer. A wheel clamp is heavier and more visible, adding deterrence in harbours and on campsites.
SCM certification
Many locks in this range carry the SCM mark. SCM stands for Sold Secure and Stichting Certificering Mechanische beveiliging, both independent testing bodies that verify resistance to cutting, sawing and forcing with a crowbar. The DoubleLock models are ART-certified, which some insurers require as a condition of cover. Check your policy before buying. Combine your trailer lock with an outboard motor lock or our full range of boat locks for complete protection.
Frequently asked questions about trailer locks
Which trailer lock fits my trailer?
Start by checking the coupling type. Most boat trailers use a standard 50 mm ball coupling, and every hitch lock in our range fits it. If your coupling is larger or non-standard, look for a universal hitch lock with an adjustable clamp. For trailers left outside or on campsites for longer periods, a wheel clamp is a good addition. It attaches directly to the wheel and works independently of the drawbar type, so both locks together cover every scenario.
What is the difference between a hitch lock and a wheel clamp?
A hitch lock blocks the connection between the tow vehicle and the trailer. Without a coupling, the trailer cannot be towed. A wheel clamp prevents the trailer from being rolled or pushed away manually. They protect against different threats: the hitch lock stops theft with a tow vehicle, the wheel clamp stops rolling or manual displacement. On a permanent storage spot, combining both gives the strongest overall protection.
What do SCM and ART mean on trailer locks?
SCM covers two certifications: Sold Secure (UK), which tests physical attack resistance, and Stichting Certificering Mechanische beveiliging (NL). ART is a Dutch independent testing body with levels 1 to 5. Trailer locks typically start at ART 2 or 3. Some insurers require a minimum ART level for theft cover. Always check this with your insurer before buying so you know your policy will pay out if the worst happens.
How do I fit a hitch lock?
Disconnect the trailer from the towing vehicle. Lower the drawbar or set it to driving position. Slide the lock over the ball or coupling, engage the locking mechanism and turn the key. Check that the lock cannot be slid off by pushing the trailer sideways. If unsure, test at home before leaving the trailer in a public car park or marina. That way you know everything is secure before it actually matters.
Shipped from our own stock. Visit our store in Joure or contact our specialists.
