"It is amazing how many people set off for a nice family day on their boat and it quickly turns to custard before they even get it into the water," Sinden said.
"I have seen a lot of boat ramp rage, when people lose the plot with each other for not following a few simple rules. I haven't seen any blood drawn yet, but on a few occasions it has been close."
To coincide with this weekend's On the Water Boat Show at Auckland's Viaduct Harbour, Ford NZ has launched a safety campaign highlighting the dangers of towing and giving boaties tips on how to mitigate risks.
More than one million people take to New Zealand waters in recreational craft each year.
But Sinden said newcomers and experienced boaties alike were falling foul of carelessness and bad tempered behaviour at boat ramps.
"I have seen some busy ramps where there are up to 10 vehicles with boats on trailers queuing to get into the water," she said.
"Tempers can get frayed and I've seen people get into a panic when impatient boaties waiting their turn start shouting at them which can lead to serious errors and accidents."
Sinden said common mistakes include people trying to get their boats off slippery ramps with bald tyres on their cars and not having vehicles powerful enough to tow trailers and craft off sand.
"The best way to make things go smoothly on the ramps is to pull over to the side before you get there and first make sure all the right equipment is in place, so that the boats can be launched quickly," she said.
"For newcomers, a good idea is to practice on days when the weather is horrible and ramps are quiet.
"Even when boats have been successfully launched, there is still plenty of potential for things to go wrong," Sinden added.
"I have seen people not tie their boats up before taking their trailer and car away from a ramp and as a result their craft has floated off and bashed into another, causing a lot of damage.
"I have even seen expensive boats sink because the owners have forgotten to put the plug in the bung hole, which is about as basic an error as you can get."
Towing advice for a safer summer
• Check your vehicle's towing capacity. Towing something too heavy could ruin the transmission as well as the vehicle's structure.
• Check the tyre pressure. A trailer may sway if tyres are flat.
• Get a mate to check the trailer's lights.
• If you have multiple axles, you might not know if the trailer tyres are flat. Hit the wheels to check. A flat tyre could cause a fire.
• Ensure there is even weight distribution on the trailer, plus check the coupling and the safety chain are fastened properly and the boat is properly secured.
• Avoid changing lanes as much as possible, as that can cause the boat to sway. If it starts to sway, remove your foot from the accelerator.
• When reversing, be sure to check for clearances.
• Before launching, as a courtesy to other boaties, make sure all your gear is aboard.
• Make sure the parking brake is on when launching and retrieving the boat.
