Trailer suspension boat damage

Has anyone else experienced problems with trailer suspension (or rather the lack of it) damaging their boat?

I have repaired several grp dinghies which have been used on 'normal' indespesion type trailers of various sorts and which have had considerable damage done to their bilges by excessive impact from the trailer. When I inspected the trailer I found that in every case the force needed to deflect the suspension arm was greater than my weight (12stone) - Having gone round numerous dinghy parks and tested trailers, frankly most of those with these systems are pretty stiff and unyeilding and would give light or fairly light (under 300lbs) dinghies a very tough ride. I ditched my own 'x' brand nearly new trailer as a result and have resurected an old Snipe with a transverse leaf spring - fine but over 60mph it occellates and causes a vibration - whats the answer? who makes a trailer with soft suspension by which I mean one which would deflect if one pressed firmly on the side of the boat when its loaded and got a nice response and which will be able to deflect at least 3" without much persuasion. I would really like to hear from a suspension manufacturer who I can use to make up a new 'soft trailer' . Aeolus

The standard indespension type units go down to 250kg total axle weight which when you include the weight of the trailer is actually too light for some boats. Most of the "standard" trailers for racing dinghies have a max load quoted of 150-200kg so should be this type.
However, if the trailer is damaging the boat, it will more likely be down to the hull supports and how you tie it on. The supports need to run right across the boat, preferably two cradles, each about 6 inches wide. These must match the shape of the hull perfectly so you don't get any point loads.
A lot of people don't tie the boat on tight enough as well - a piece of rope tied across certainly isn't enough. A decent webbing strap is essential, with a mechanical means of getting it tight (ratchet or lever type) wound on until you can play a musical note on it. If you're worried about crushing the boat, arrange it with a ratchet down each side rather than one in the middle so you're pulling the boat down and not inwards. The loads caused by a boat bouncing around will be far more than you'll get on with the strap, and most likely the boat will move to the wrong position on the trolley and put a massive point load on it as you hit the next pothole.
Most importantly though, using a proper 3 tonne load 50mm ratchet strap to fix the boat on the trailer instead of that old bit of rope could one day save your life. If you're rear ended at speed on the motorway, you want the boat to break apart at the points where it's secured to the trailer rather than have it end up inside the car.

Given that you can legally tow a boat at 130kph (about 85mph) in some parts of Europe, I'd hope any professionally built trailer could cope with that sort of speed. Mine is certainly happy at that speed with no oscillation or vibration.

where did you find the information about legal towing of trailers? I looked loads of places before i towed my boat to find out the rules and regulations and found nothing.

I've found that most noise and vibration is actually caused by the straps used to tie the boat down and the cover if you keep that on when trailing and not the trailer itself.

Originally posted by timnoyce where did you find the information about legal towing of trailers? I looked loads of places before i towed my boat to find out the rules and regulations and found nothing.

It should be layed down by your version of the "Roads and Traffic Authority". you should be able to find out the following

1. Brakes/braking systems required
2. Maximum towing weight for YOUR tow vehicle
3. Maximum Length of your combination
4. Maximum rear/front overhang
5. combination lengths
6. etc.

Originally posted by timnoyce I've found that most noise and vibration is actually caused by the straps used to tie the boat down and the cover if you keep that on when trailing and not the trailer itself.

As for noise from your tie down straps, simply put a half turn( so the bottom of your strap becomes the top) this stops the fluttering

 

Edited by Skiffe