Boat gets launched at intersection with a passenger in it.

[GTA Driver]

At the 12 second mark, someone is moving in the boat

 

[IAmATeaf]

So was it his emergency stop that unsettled the boat? Can’t have been that well secured?

 

[GTA Driver]

So was it his emergency stop that unsettled the boat? Can’t have been that well secured?

I have been thinking about that. My dad trailer-ed an 18 foot aluminum boat between 1984 to 1988. I can't find any images similar to our boat trailer, but i feel the way it was designed its would be less likely to fall off during transit. I also feel, given that it fell to one side, the boat may NOT have be loaded on the trailer evenly or properly. There are also straps, but it appears on google images, few trailers have a portion on them to place straps or "Transom tie downs"

I was a very active boating fisherman between 1984 to 2010 and I can't recall even hearing tell of a situation like this. I used to spend 2/3 of my summer weekends on a cabin cruiser docked in a marina and I wasn't far from the boat ramp.

The trailer on the first boat my family had wheels

The one in the video is what I would kind of plank type
I can't see some plank type trailer (not sure what the correct term is) as being that stable or offer much security during transit.


Perhaps "Transom tie downs" would have made a difference, but looking a google images, few trailers have them. The boat that fell of the trailer doesn't.
The 35 second mark of the below has "transom tie downs"

The 50 second mark of the above video, it appears to have some kind of structure on that may block the bow from moving forward from a hard brake. Also he refers to the bow hook and not removing it until the boat is in the water as sometimes boats backing up the boat have had it launched prematurely. Boats meeting their demise as he puts it. Perhaps, the boaters in the first video did not have winding reel secured.

In fact, at the 9 second mark of the video where the boat fell of the trailer, I can't see a reel for the boat unless it broke off.

 

[Nigel]

In fact, at the 9 second mark of the video where the boat fell of the trailer, I can't see a reel for the boat unless it broke off.

At 2:40 in your video he says "now put the safety chain on".

Clearly in the OP video the safety chain was not fitted, or broke, probably not fitted. If it had done its job then it would be impossible for the bow of the boat to leave the trailer, might allow some movement, but not to leave the trailer.

Of course the safety chain should not be needed, must have also put the brakes on too hard, presumably a result of driving too fast. And then there is the issue of having someone riding in the boat, clearly not a group of people who have any respect for safety, so quite likely they didn't bother with the safety chain.

 

[GTA Driver]

A safety chain would be a good idea, but I can't recall our trailer having such thing. Simply a winch, which as a fisherman, I would call a reel.

Looking https://www.karavantrailers.com/marine-trailers/boat-trailers, I can't see one

For their larger boats, say up to 27 feet, they make mention to "COATED SELF-COILING SAFETY CABLES ", but I see nothing around the winch.

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There a cables close to the hitch, where are perhaps the COATED SELF-COILING SAFETY CABLES . This would hooked to the car I believe and NOT the boat

Looking at the design of some of the trailers, I don't know how they get approved or if there is such a review of these thing for various provincial or state department of transportation. In Ontario, I know the trucking industry is monitored. At least every time there is a major accident, they seem to do a safety blitz

 

[kamkar]

A few years ago i saw, granted a larger model Audi, but the motor boat it was towing looked a bit too much even for a big Audi.
That big i assume there was a brake on the trailer too, cuz if not if the car slammed on the brake the boat on the trailer would be pushing it wayyy past normal stopping distance.

I can only assume that here a boat must also be secured just like any load on a bed or trailer ( not that this seem to bother Danes much )
Actually a few days ago i saw a semi with a 20 foot or so low ( 3-4 foot tall sides ) skip / open container like thing on its back, you know one of those it can put down outside your house and you then fill with stuff the truck return later to pick up.

But in that "bed" there was a mini digger and several other things like compactors ASO, none of it secured just a tiny little bit ( the few Danes that do secure stuff on their vehicle think you can just tie a bit of clothing line and that will secure just about anything )

 

[Nigel]

Looking at the design of some of the trailers, I don't know how they get approved

UK doesn't seem to have any boat specific regulations for trailers. It does appear that to stop the boat sliding forward under heavy braking, it should be held:

1. At the front by the winch cable, which should be locked tight by the winch brake.
2. At the rear by one transom tie down either side which will prevent the boat moving forward and keep it pointing straight ahead.
3. For backup by the safety chain, which should prevent the boat setting off on its own journey separate from the trailer.

Even if there is no specific law, you are still responsible for safety, and you should follow the normal best practice/guidelines.

My dad trailer-ed an 18 foot aluminum boat between 1984 to 1988.

Back then, the trailer was probably designed for a vehicle with drum brakes, and most people had the sense not to brake too hard!

 

[GTA Driver]

Although its a good idea to have safety chains and tethers, failure to remove them can be problematic too.

 

[Nigel]

Maybe he had a car but no trailer waiting at the other side?
Didn't seem to be a huge problem.

 

[kamkar]

Dident mythbusters do a episode on boat + trailer once.

 

[DT MI]

Dident mythbusters do a episode on boat + trailer once.

Yep - https://en.wikipedia.org/wiki/MythBusters_(2005_season)#Trailer_Troubles