Boat Trailer Preventative Maintenance
A well-constructed boat trailer can last decades. Unfortunately, it is an often-forgotten component of a BMT (Boat Motor Trailer) package.
My three Felk trailers were made in the 1980s but have been dunked countless times in salt water without letting me down.
All three trailers are multi-roller, which makes launching and retrieving the boats much easier than keel roller and bilge pad trailers. For this reason, there has never been a need to immerse the axles and springs. But despite some boat owners stating that launching and retrieving a boat on a keel roller and bilge pad trailer requires dunking the axle, I have found that with free-spinning keel rollers and a five-to-one geared winch, the axle and springs don't need dunking. My last project boat — a 4.3-metre Clark Navigator runabout powered by a Suzuki DF40 sitting on a Dunbier trailer — was easily launched and retrieved with the axle and springs out of the water.
Not immersing the axle is important because, after towing to a launching ramp (even a short run), the wheel bearings get hot. Dunking the axles immediately after a run rapidly cools the wheel hubs, drawing salt water into them which can damage the wheel bearings and rapidly shorten their lifespan.
I also recommend fitting Bearing Buddies, which make packing the wheel bearings in grease much easier than removing the wheels and bearings. Be careful not to pump in too much grease with a grease gun, or the inboard seals can dislodge and the grease will leak out. If the Bearing Buddies are working correctly, the spring-loaded outer plate surrounding the grease nipple will slowly move outwards as the hub is filled with grease.
To reduce corrosion of the untreated steel axles and springs, I brush on used engine oil mixed with kerosene — there’s no fear of polluting waterways here, because these components are never immersed.
Two of my Felks have a tilt function, meaning the back of the trailer is immersed during launch and retrieval. As both trailers originally had submersible lights which only work for a couple of dunkings, I fitted removable lights and wiring. Not only does this extend bulb life, but it prevents light fingers pinching the lights when I'm out on the water. Once I parked my car and trailer at Church Point on Sydney's Pittwater only to return and find all the lights had been stolen. I had to drive all the way back to Crows Nest with no trailer lights. Thank heavens it was during the day, as there's no way I could have done this at night.
On tilt trailers, the aft cross members will rust over time. When rust starts appearing, sanding back the affected area and brushing on zinc chromate (two or three coats after a drying period) can prevent the need to cut out the aft cross member and weld in a new section.
All three Felks have winch cables — not straps — and I frequently spray these with WD40. The Dunbier had straps so it was very important not to let this twist while winching the boat up the trailer. Also, it’s a good idea to check for any fraying of the strap around its edges, as a broken strap will really ruin the day!
Finally, don't forget checking and maintaining the right tyre pressure and looking for cracks in the side walls. Admittedly, most older trailer tyres had inner tubes, but dirt can reach the tubes and slowly abrade against the tyre fabric as the side walls start to crack. The old eight-inch wheels common to small trailers in the 1970s and early 1980s had only a four-ply rating (like most modern car tyres) but ran at 65 psi, so were easily damaged by sharp stones at a launching ramp. Ten-inch tyres had a six-ply rating, ran at only 40 to 45 psi, and were under much less stress. The more common 13-inch tyres run at normal car tyre pressures of around 30 psi and, being steel belt radial, are more resistant to punctures despite being tubeless.
Keeping tyres away from direct sunlight when stored in a backyard will dramatically increase their lifespan because they are not subjected to UV rays, which rot away tyre side walls. My Felks are running their original tyres, with only one tyre out of a total of six having a slow leak — but with many inner tubes showing a decline in quality, it’s a small price to pay for retaining the higher-quality tubes of the old trailers.