At the ramp couple days ago, winding in the boat on busy ramp and just got 1/2 snugger upto the rubber V thingy...
CRACK
The eye in the bow snapped one side out....hooking the shackle on was pointless... so a slow climb up the ramp and to one side....being a ex boy scout.. open the trunk , pull out the heavy tie down, around the front bolard, around the trailer behind the hitch, back up and pull tight... 2 rear tie downs and off safely home.

We have often scoffed at  threads/posts/ pics of boats sliding off , at the ramp and on the roads , unintentionally....but maybe more unjustified that we realise.

 
We have had the boat coming up 5yrs... just before buying it the front tow eye had been replaced on a service....receipts.. I wonder why?
It is a 5.5m glass boat, all up, motor, gear, fuel etc with 3 guys about 1100 kg tops.. so boat on the trailer under 1 ton.
 The eye is (was) 8mm stainless.
When one 'eyes up how it aligns with the hook, as pulls up is factionally high (more loading on the top side, and when pulled into the rubber V pulls almost square down to the hook/ shackle etc.


 From the pic you see there is a substantial area in the break that shows it have been fatigued for a while.... that is scarry

I have replaced with a 10mm...drilled out the top hole, drilled a new hole for the larger span....epoxied and hammered a dowel into the obsolete hole.
 Then pumped marine urethane sealant into the new holes, smeared the new eye shafts and bolted into place.
 With using the top hole, and new bottom, it has lowered the centre 'pull/ loading area of the eye to give better even loading when pulling the boat up AND when shackled, etc on the road.

Steps, bad luck. it could have been a lot worse if you lost the boat of the trailer.

My Kevlar rope snapped with only a small sign of possible wear... aye time to really check things over.

You just never know what perils lie beneath that nice shiny metal.

Remember once at the ramp,winching the boat on and the attachment on the bow holding the winch hook carried away under load. The whole lot went flying past my head at speed  with inches to spare and came to rest in the open boot of the station wagon.

Espresso wrote: My Kevlar rope snapped with only a small sign of possible wear... aye time to really check things over.

http://www.explainthatstuff.com/kevlar.html

But, as STEPS photo demonstrates, you shouldn't rely on the towing eye as the only thing to hold your boat on the trailer.

 No but certainly your concept is there

 Actually all that.. the tie down.. the winch and safety chain ALL go to the bow eye...
 If that fails there are 2 tie owns between the stern and trailer that still prevent the boat from moving backwards.

I have often 'shudder at the practice of a tie down across the gunnels.. to hold the boat down in the rear... If the eye fails.. the boat will still slide a substantial distance rear ward... enough to cause serious mis balance, which under fast slowing causes huge handling issues... chain reaction to disaster.
Also using tie own if tightened enough to prevent rear movement creates massive squashing stress on ther hull of the .. puling the gunnel's in and pressure on the guide rollers and hull pressure points

Then there are those tail lighting bar things strapped across the gunnels .. also used to hold the boat down...boat breaks away, they break , boats on the road. Also seen a few yrs ago a boat with one of these, got into a serious sway... not quite jack knife.. lot weight in the boat coming home from holiday.. and to find the trailer light bar seriously cracked

2 tie downs going from the top of the stern, either side of the motor here it is bolted to the stern, down to the rear trailer cross member.... some non keel trailer boats have to have to crawl under to hook up... keel boat trailers the cross member is a few inched back under the hull..

Wonder if bow of boat is able to move up and down when being towed.

I use the winch, no worries, but also have the u-bolt shackled to the second eye. Bit different being on an alli hull though, no way the eye itself could snap.

Mate, not if you saw how this thing is welded on.... solid is too insufficient a word to use....

I do sometimes wonder... with safety chains (both the one from trailer -> drawbar and winch post -> winching eye) how many people are using rated chain and shackles?

 Yep Damn good point...
 Fail trailer WoF if have a stainless shackle... even if weight rated... Stainless doesnt like shock.... which is why things like spring shackles, cross member bolts are not allowed to be stainless. So if your WoF guy has passed your trailer WOF with a stainless shackle I would be consented at what else has been let by...
 As to the chain to the boat.. dont quote me on this, from memory that is to do with owners responsibility to have a secure load.. not a WoF issue (???)