Using straps is a commons way to tie down a kayak, and work easier than ropes…and NEVER use bungees to secure a load! A recent posting on how to lift and load your kayak gave good advise except when author said you could tighten the straps on a plastic boat as much as you want. I’d question that broad statement - First of all you should strap your boat at strength points along the hull, typically at bulkhead locations so the hull has less tendency to “oil can” or collapse when the plastic softens when heated by the sun. That’s why tightening too much is bad, the softened plastic deforms and needs to be unloaded/loosened from it’s bindings to re-form (a long wait if this happens on the way to your put-in point). Also, a tip on aligning the straps. If you put one or two twists in the strap it won’t tend to buzz like they do at higher speeds when tightened without a twist…where they act like a musical reed and vibrate like a swamp of angry, giant bees. As always Be Safe; Have Fun out there!
To your point, yes, the straps definitely can be too tight and cause damage:
https://forums.paddling.com/discussion/2938164/is-the-strap-tight-enough/
Probably not quite as easy to do with a standard cam lock strap vs ratchet strap, but still possible to do. Ratchet straps are boat killers.
It’s sometimes amazing that one less ratcheted stop is too loose, while one more ratchet squeezes it too hard.
It’s strange to me that although I use cam straps now after years of reading about them, I used ratchet straps in the beginning and never used to tighten them too hard on my kayaks.
I had to use the hammer to release the cams on the straps after a freezing rain/cold temp event. I think knots would have been a bigger pain.
Lots of livery folks use bungies on canoe trailers but that’s not my cup of tea, I’d be more worried about taking someone’s eye out than having a boat fly off though.
I always seem to have more humming, with straps or ropes, when hauling canoes. Rarely have humming with kayaks. They’re just not as musical (irritating).
All of my kayaks are oil canned, strapping is only part of the cause. Leaving them on the rack all week doesn’t help. Some ww boats (creekers with lots of rocker) don’t like to ride hull side up on the roof rack so they are more likely to get damaged… The hull area under the kayak seat usually gets damaged first so I try to avoid putting that directly on the cross bars.
The last two boats I bought both had some oil canning when I bought them. I just look at them as expendable junks of plastic. Usually I wear a hole or crack in a hull with 3 or 4 years of use (150-200 day trips). A really good ww boat will last 300 or 400 trips before wearing out. Eskimos and Prijons have a reputation for lasting even longer but I’ve never owned either brand. The last two kayaks I bought were less than $250 a piece. So I buy cheap and intend to abuse and then replace them. I’m Doing well if I keep them from falling off a vehicle.
My shape shiftin’ poly canoe (MR Adventurer) is a little wavy now all along its puesdo gunnel line. That’s from strapping it down tightly on the rack. It doesn’t seem to affect how the boat paddles, just a cosmetic issue.
In general, just expect some shape shiftin’ with poly (especially canoes ) and you kind of look at deep hull gouges with pride if you enjoy hittin’ rocks as much as I do…
I used WD40 or Liquid Wrench on my strap buckles to keep them from sticking. I was in a salt water environment so always rinsed entire network off at end of day so really never had them stick anyway. Also, regarding the humming strap, put a couple of twists in the strap as you tighten it. It won’t affect the strength, but it will keep it from vibrating like a reed and making that noise (usually).
Keeping buckles lubed is a good idea, esp. around salt water. After years two of my NRS buckles failed but I had never rinsed them.
I’m a rope guy. Wouldn’t use a strap if I was paid to. Nothing but twisted nylon and the ropes I use are 13 years old, have never slipped, never scratched, chipped, or deformed any of my boats.