Boat Transom to Trailer Tiedowns??

[TREVELLY]

I have had tie down lugs added to transom on boat and the trailer a dunbier has loops to attach these too.

What do you guys use on similar size boat - ie 6.25m.

I do not want anything flimsy as with a small tinnie.

I see in US they have a product called boat buckle - is anything local?

Most ratchet straps are way long - I am going from loop to loop about 1 metre or just less.

Also better if set up is one piece each side and quick and easy to fit not a chain, turnbuckle and shackles as with the front of the boat.

Truckies have something called "web dog" looks great but real heavy, probably too long and expensive but one piece.

[Fed]

Stainless ratchet straps cut them off to whatever length you want, hook on each end.
https://www.juststraps.com.au/Default.asp?
I prefer one each side at the back I think it reduces the chance of the boat squirming under one long strap over the top if you get what I mean.
Not a big fan of pulling down too tight or turnbuckles either either.
I had a couple delivered from juststraps last week, quick service & good gear.

[Chimo]

Trev

I use short "Tow 2 Go" ratchet straps from the Vagabond transom ski hooks to the trailer loops that are probably what your after. I think I got them from whitwooorthhs.

Cheers
Chimo

[wags on the water]

2000kg ratchet straps - 625 Cruisey. 1 each side from ski hooks to welded loop on trailer - doesn't need to be stainless. I spray mine with silicon spray once a month. You can shorten the straps to the length you require bu using the hot knife feature on a butane torch - seals it as it cuts. As extra protection between strap and boat, cut up some carpet.

[Chimo]

Trev

Also have a look at Bullivants eg 421126 cut to your length http://www.bullivants.com/Uploads/bullivants_quart.pdf

Cheers
Chimo

[cormorant]

I don't trust trailer tie down points and always go around steel section and we just use the beaver truck ratchet straps 50mm and 75mm. The 75 didn't humm at highway speeds as we never had a lot of tension on em. Not stainless and never in the water but by the XX years when they look shitty they are due for replacement or new webbing. Webbing is rated and has exp dates along with wear and UV threads in it and we ran abrasion covers for the short lengths so UV never got at em.

We looked at others and they are just not rated heavy enough if I ever got really loose on the road ( aka Shy guys) or had a head on disaster I want the boat attached not in the back seat. At 3plus tonne cat we had bows dogged down lightly and 50mm straps to each rear bollard and one over the strap over the stern . On freeway work we threw a extra safety back deck behind the cabin. Non of then really tight just firm as the trailer flexes and hulls don't.

Beaver also do a lesser rated overcenter one in stainless but I haven't seen one in the flesh to know if I would use em on a smaller boat but they look like they have a locking pin not like teh cheapos that just use tension. .

People need to get to terms with lashing capacity and real life working loads and breaking loads. Going undersize and using things beyond their normal life is a bad option and the straps handed out with some package boats are dead set dangerous for all but a empty hull. A member on here was a rigger and straightened out a few myths last time this was discussed if you do a search.

Having a few mates with trucks and them doing updates on load restraint courses he gets scared when he see some boats on the highway with pissy little straps attached to crap tie down points on thin walled RHS on trailers. Cross strapping at the stern may give a better result if your points can take anything other than vertical load as it will still allow trailer to flex but someone who knows more might want to comment.

When sh yguys is through his insurance ( god I hope he gets sorted) I'll be intersted to hear what straps he had and how they failed and honestly since no one was hurt in his case it is probably a good thing the boat departed as if it was still attached it may have caused a rollover or with a hitch failure ended up in the back seat. Totally different scenario is someone was hurt or another oncomming car hit a loose boat. A lot a luck in that accident and glad they walked away.

What we used as our dogs rather than turnbuckles as they are fast and simple- I hate turnbuckles ( PIA) and chain dogs unless it is solid machinery that can take the tension.
http://www.beaver.com.au/?stm_a=77|&...=3155&tpi=5681

http://www.beaver.com.au/?stm_a=77|&...=3155&tpi=5681


http://www.beaver.com.au/?stm_a=77|&...=3155&tpi=5681


To shorten the webbing we used to clamp it between 2 blocks of wood and hot knife it and then use burner flame to melt the ends properly so it wouldn't unravel and was still easy to feed into ratchets.

[WalrusLike]

You know in thinking about this it seems that the extra strap I have right across both sides of the transom and down to each side of the trailer might not be the best solution.

Ideally you want something that exerts no downward or inward compressing force but that stops the boat lifting off rollers after road bumps.

A solid brace with adjustable height and a padded c shaped collar for going over transom would be ideal... One for each side. Bottom of brace has hook for the eye welded on trailer.

It would absolutely resist upward movement because it's a solid piece and yet place no force on the boat hull.

Seen anything like that?

[The-easyrider]

I have some 25mm straps with ss hardware used in the same set up as you and have no doubt as to there ability to keep the boat attached to the trailer.

[Micadogs]

I use webbing straps, rated at 900kg each, on each side of the transom. I have a total BMT package weight of less than 1500kg. My boat hull weighs 600kg and the motor approx 200kg.

These webbing straps dont go into the drink ever, and are always checked for freying and other damage.

[WalrusLike]

If my 'solid' brace is made out of 6mm x 75mm aluminium strip then it should be strong and light. Height adjust by dual half length with overlap and double bolted. No force on boat other than resistive when inclined to bounce.

Might not solve the moving forawrd issue during a prang but will stop lifting off rollers.

[TREVELLY]

Thanks for ideas guys.

I do know that when designing crane lifting we use a safety factor of 3.

That is the item weighs 400kg hence breaking or ultimate capacity of lifting strap 1200kg.

In a crash situation? You could strap it tight to the end of trailer with a couple of 2 tonne straps and then the fixings in the trailer implode.

In a failure like shyguys (and I say maybe) just locking it downwards at the back then you would get away with safety factor straps rated 3 times but in a crash or sudden stop it is a different ballgame. Doesn't mean whole rig will remain stable and not tip on side, just means boat remains on trailer.

Actually the lock down at the back is a tricky number to establish as you are only trying to stop uplift and some horizontal forward force - uplift is more likely determined by the weight of the trailer rather than the boat. Forward force is shared with back and front - so how much??? Forward force is best taken down to drawbar.

Forward motion is taken a lot at the post location hence locking to draw bar is better than top of post especially as posts often rust out inside and fail at base.

I am digressing but I suppose all things considered if I have a boat weighing 1.5t and 80% at back and a safety factor of 3 then 1.5x0.8x0.5x3=1.8tonne capacity to each of two straps but the boat trailer weighs only 0.5t but that is okay as with a safety factor of 3 then strap only needs to be 0.5x0.5x3=0.75t, but takes no breaking force into consideration - looks like 1.5 to 2t is something closer to right and only for swerving and braking not for sudden impact or crash.

Just my thoughts on what I will rate my tiedowns with - not a recommendation for others - do your own numbers

Chimo - that site is a bargain - mate I am there - two straps rated 2t each for $16.50 each - cool.

Thanks guys and lots of good ideas and suggestions how to make strap shorter etc.

[cormorant]

Page 70 and you get some ideas . Not sure if this is the latest study and regs but a good read with photos. I think Shyguys unfortunately could feature in the unexpected accident section photos.

http://cottonaustralia.com.au/upload...aint_Guide.PDF


From non rated u bolts on winch posts to non rate chain on bow tiedown and no propper fixing points we need to calc the full weight on a frictionless surface. Looks like ( direct lashing) cross strapping ( to get angles required) with 2 straps on lugs either side rather than at the stern and 2 at the bow covers a large boat. Bloody scary when you see the photos.

Was interested to read ( had never understood why) that they say most restraints fail at low speeds as modern brakes can apply such a great braking force at those speeds and cause a shock loading higher than breaking strains. Makes sense now.


To think I used to tie down wool bales with hemp rope but I guess the old trucks could never brake hard and there was lots of friction. The oldtimers were bloody good at it and I just followed their lead of how to do it.

[TREVELLY]

Trev

Also have a look at Bullivants eg 421126 cut to your length http://www.bullivants.com/Uploads/bullivants_quart.pdf

Cheers
Chimo

Cormorant i see they are using a safety factor of 2 times for breaking on P70 of fixing.

I am looking to use a safety factor of 3 and the straps are pretty cheap as per Chimo's post . I have one of those at home and for sure it has very secure hooks and good solid rachets not the pretty stainless but very industrial.

Acacia Ridge is not where I want - try and find somewhere North Side.

[cormorant]

Any truck wholesale place will have them at low prices and the beaver ones are better straps , handles IMO than some cheap imported ones. Just used to them I guess so others feel lighter and different. With my ones the bottom pin of the ratchet can be the place the hook attaches after the short strap has gone around the trailer chassis - not all others you can do that with and also with the hooks supplied you may have trouble attaching then to small places so the dogs ones with cast hooks may work better? . There is lots online stores including bullivants.

[Mr__Bean]

For larger boats I don't think it is about the weight of the boat, I think it is about the weight of the trailer.

After hitting a large bump the boat is pushed up hard by the trailer skids or rollers, that mass (the boat) then has to lift the weight of the trailer with the straps to keep the combined load (boat and trailer) together ready for the landing.

I think it is about keeping the trailer strapped up under your boat.

Darren