Back tie down ideas

[Kremo]

Now y’all have me wondering if my ski is safel!!!

[Stanelyn32]

When I see such pictures, the first thought in my head is 'OMG, it will be dirty as hell by the end of its trip'

[steve45]

Yes, I think periodic strap replacement will be on my list of maintenance items.

I was really surprised when I broke a strap on my nephew's trailer hoisting an old STS 750. I don't think those things weigh more than 500 pounds or so.

We live in a part of the country that has very high UV exposure and it tears up everything. I'm in the process of extending the awning over my toys at our lake house by a few more feet to try to reduce sun exposure.

I've had a new strap for my boat trailer laying around my shop for a couple of years--time to put it on!

[K447]

... I think most boat winch straps and tie-down straps are a lot weaker than their original rating.

Exposure to sunlight ...

I had not fully considered to what degree sunlight exposure might weaken the winch strap webbing material in the first few years.

Apparently the strength reduction can be in the range of 30% or more in the first year, for a strap exposed to full sunlight all day, every day. Second year % reduction is not as drastic.

https://www.cargoequipmentcorp.com/what-are-the-affects-of-uv-and-weather-on-winch-ratchet-strap-webbing

https://factor55.com/uncategorized/uv-degradation-of-synthetic-winch-rope/

I will admit this is a greater strength reduction percentage that I might have guessed, for the first year and then the second year. In my seasonal climate the trailer and winch straps are stored indoors for half the calendar so hopefully the rate of degradation is also less. During the summer season my PWC trailer does sit outside with direct exposure to the sun.

I had already intended to replace the bow winch straps every few years. Right now those winch straps have been on there for four summers. I have not noticed much color change nor surface roughness (which are indications of strap degradation) but I should more closely compare my on-trailer winch straps with a rarely used entire 'spare' winch tower assembly, including a nearly new winch strap.

Which raises the question - what is the optimal age to proactively replace old winch straps with new?

I do see lots of trailers with frayed and clearly degraded winch straps, either from many years of exposure or from frequent use. I suspect many PWC trailer owners intend to use their original winch strap right until the day it fails entirely.

I suppose the same degradation issue affects my ratchet tie down straps. 2ÔÇØ wide Boat Buckle brand. Two straps on the rear of each ski are mostly in shade during the day but the front safety straps are exposed to the same sunlight cycle as the bow winch strap.

[KEYZBUM]

Looking at post #4 again, that doesn't look very secure. Yes, those straps fasten to the metal fender bracket, but those things are easily bent. A lot of trailers have plastic fenders, too.

In reality, I really don't think any straps are going to hold a large 'Ski or boat in an accident. A 2" wide nylon strap is what they make seatbelts out of to hold a 200 pound occupant inside a car. Put that same strap on a 1000+ pound 'Ski and think it's going to hold? Same with the bow stop. If the boat doesn't go over it, it will just knock it out of the way.

I just did that for the photo, normally it has the seat on and strap goes around frame back to strap
My fav test is put 1 dollar bill on top of each bunk-under hull next time you tow with angled straps and see if it is still there after the tow..

[steve45]

That's a really scary video!

That said, I think most boat winch straps and tie-down straps are a lot weaker than their original rating. Exposure to sunlight destroys the thread that holds the hooks on the end of the straps. I know I've seen several straps fail while winching boats/PWCs back onto the trailer. It wouldn't surprise me if the straps lost half their initial strength after 2 or 3 years.

[K447]

... I really don't think any straps are going to hold a large 'Ski ... in an accident. A 2" wide nylon strap ... on a 1000+ pound 'Ski and think it's going to hold? Same with the bow stop.

If the boat doesn't go over it, it will just knock it out of the way.

In a severe collision, the idea is that the hull does not leave the trailer. The trailer frame may bend and twist. The ski just needs to still be attached to and in the general vicinity of the trailer structure when everything comes to a final stop.

Sure the winch post may fold forward, but if the bow strap is still connected to the frame it should absorb a lot of deceleration energy. Same with the rear straps. Mine are rated for 1500 pound breaking strength (each), so with a 1000 pound hull that is 3 times the deceleration force, plus up to another 1500 pounds of safety strap pull at the bow. Plus the winch bow strap, rated for at least 1000 pounds with breaking strength somewhere higher. Overall the four straps should hang on to several G of trailer deceleration.

The tow vehicle will be decelerating as the crush zones do their thing, and the trailer behind will potentially buckle if the vehicle ball mount manages to stay attached. All together, if my watercraft are yanked free of my trailer, something very bad has happened.

Do the best you can with regards to trailer selection, trailer configuration and how well the watercraft is strapped down.

Some may not have seen this trailer crash test video.

https://youtu.be/5A9fXXDHfl0

[steve45]

Looking at post #4 again, that doesn't look very secure. Yes, those straps fasten to the metal fender bracket, but those things are easily bent. A lot of trailers have plastic fenders, too.

In reality, I really don't think any straps are going to hold a large 'Ski or boat in an accident. A 2" wide nylon strap is what they make seatbelts out of to hold a 200 pound occupant inside a car. Put that same strap on a 1000+ pound 'Ski and think it's going to hold? Same with the bow stop. If the boat doesn't go over it, it will just knock it out of the way.

[steve45]

Safe to assume this guy hasn't read through this thread

Yea, but maybe he's not going very far.

[K447]

...

In other threads I have posted info and photos on how I recommend setting up a PWC trailer and how the winch post, bow roller and winch strap should be configured.

I do see other trailers that are properly sized and configured for the PWC that it is carrying, but that is actually quite rare. Even among experienced PWC owners that have been riding for years, often their trailer set up is just not very good.

An undersized trailer is usually the first thing I notice. If the trailer frame and bunk ends are way forward of the hull rear, you know the rear tie down is going to be mediocre at best. At the front, no safety strap, and often the bow roller is at the wrong height and the winch strap is routed incorrectly.

If the trailer is unloaded, often you can see grooves in the bunk carpet where the hull strakes have been grinding into the carpet. Which means the bunk boards are not set up to fit the hull bottom properly.

And so on.

[Xspook]

Safe to assume this guy hasn't read through this thread

[steve45]

Another Boat Buckle fan here!

These are the small ones, which I have switched out to the larger ones.

[KEYZBUM]

Wow Perfect. Dam you make it hard to argue..Ok and I hate being a K447 fanboy But Damit..
The ski and trailer act as 1
Perfect.
dont think I have even seen it done Perfect like that,except on a 4 place trailer.
Mine only has th1 strap to break , your has 2 ..

[K447]

The number one way to improve how well the rear of the PWC is held down to the trailer is to use a trailer that is actually long enough to properly fit the hull.

The majority of PWC trailers I see are way too short for the hull they are carrying.

And even if the trailer is (almost) long enough, the winch post, and therefore the hull, is often positioned much too far back on the trailer.

Having a long enough trailer is not about rated weight capacity of the trailer. It is about having the trailer frame and the bunk ends extended far enough back to fully support the hull and provide proper angles for the tie down straps.

So often I see rear straps that are angled far forward at a shallow angle, not so much holding the hull down as they are merely tensioning it forward. On a hard road bounce those angled straps are not going to prevent the hull from lifting off the bunks.



This is my current trailer configuration. My previous trailer was similar. Note that the bunks extend a few inches behind the hull rear and the hull is fully supported. The ratchet straps are vertical, or nearly so.

Also, the ratchet straps I use are 2 inches wide and have a fairly high weight/load rating. They are sold as boat transom straps. These are sold under the Boat Buckle brand, the stainless steel model. Load rated 500 pounds, breaking strength 1500 pounds. Per strap.

Imagine the entire trailer and PWC load was lifted up and inverted in the air, so the hulls are hanging from the straps. Would your inverted watercraft stay in place against the bunks? Mine probably would.

[Xspook]

75% of the time the back straps will work, but watching my friends ski's bounce when I drive behind them , makes me wince the whole time..

I use two separate ratchet straps, 1 on each side, connected directly from the trailer to the tie down points on the stern of the ski. Of course, I'm not behind it and can't see what's going on, but I doubt very seriously my ski bounces off the bunks and feel confident if I were to make an emergency stop, they would hold that ski in place.