Advice for working with cam straps
The other day I got an email from our friends at NRS asking why we haven’t done a cam strap review. At first our team was wondering what we could say about NRS straps that boaters don’t already know. Everyone has them, they are super ubiquitous, and we all use them for whatever…easy right? Well after talking to several boaters there’s a lot more to the strap game than meets the eye. What size straps should you use for an oar rig? How strong are they? Should we be using them for perimeter lines? What about flip lines? There’s actually a lot to the subject so we thought we’d take a crack at it.
Cam Strap specs
First we need to get a baseline on what an NRS cam strap is so let’s look at the specs so NRS sent us this handy guide:
Strap Material - Polypropylene flat webbing with a proprietary UV coating
Minimum Breaking Strength (MBS) - 1” Heavy Duty Strap is 1,500 lbs.
MBS - 1.5” Strap provides a 2,000 lb. breaking load
Working Load Limit – 500 pounds for the 1” and 650 pounds for the 1.5”. Working Load Limit (WLL) indicates the maximum load that can be safely held by the strap when in use.
It’s important to understand what these straps are made out of and how much abuse they can take compared to other forms of rope and strapping. For more info on that you can see our article on rope and webbing.
Ideal Uses
There are a ton of fantastic uses for Cam straps, but there are also some spectacularly inadvisable ones as well so we thought we’d clear up a few of those points and it really goes back to NRS’s founder Bill Parks and why he set out to create the strap system we use today. Bill first created the strap after a string of accidents in a high water year on the Middle Fork of the Salmon River. There were some bad situations that he thought could have ended better if the gear on boats had been easier to remove after a flip.
Bill boated with some folks who swore by tubular webbing for securing gear. Old habits die hard in the river world, but it really has become and industry standard to cam strap gear down. It can work with tubular webbing when done right. You need to know your knots and use ones that hold well but can be untied easily. Why make things harder in yourself thought since some types of webbing and rope stretch when wet and shrink up again when they dry, which can be problematic for river use. So what should we be using Cam straps for?
Cam straps are great for oar frames where multiple straps are involved and the total force exerted by the rower would be far less than the working load limit
Tying down gear to vehicles
Storing gear internally in a raft goes without saying
Setting up a single person hammock
Drying gear
Other than that cam straps are generally useful in any light duty applications
How is it in the water?
As the story goes Bill designed straps to fill a particular role, but strap technology is constantly improving with material science and raft guide ingenuity. There have been some cool strap designs and updates that have come out and are super useful for river applications:
Loop Straps - come in two parts, with a loop on the end of each, which allows you to hitch each side to a raft frame or roof rack. Rafters love them for uses like strapping down a cooler or dry box because you don’t even have to take the webbing out of the buckle, just loosen them and push aside to open the lid.
Buckle Bumper Straps - are totally worth it for protecting your vehicle or expensive composite kayak. All you have to do is once toss an unprotected buckle over the vehicle and hear it crack a window to appreciate the Buckle Bumper! You can also remove the bumpers and transfer them to any other NRS strap.
Grab Straps – These straps are designed to go around a thwart and have a handle or two sewn into them. These straps are super effective at providing an additional contact point for a rafter in the boat. They are great for kids, bow paddlers, monster surfs, or if you are dropping steep waterfalls.
How tough are cam straps?
This really depends on how you use them going back to our data from the cordage institute we can see some interesting properties with cam straps.
Polypropylene is actually a lower tenacity fiber with quite a bit of elasticity and creep under loads. It’s super important to keep this in mind when you are using them under loads. That being said NRS cam straps don’t change in their MBS when wet, have excellent rot resistance, excellent UV resistance, Good abrasion resistance, and the strap itself will float (though not the buckle so if you drop a 20’ in 15’ of water there is a good chance you will be able to find the tail and retrieve it)
Important considerations for using cam straps
The best general rule would be to consider the working load limit of the strap and plan accordingly.
If you are using them as tie downs remember the WLL from above. We see a lot of guides use these on boat stacks on trailers. They tend to work well in this capacity, but it is worth noting how big your boats are and how many you have on the stack. If you have 5 boats at 125 lbs per boat and you throw only two 20’, 1” straps on there you are actually outside the WLL of those and you will probably lose some bats at some point. Consider more straps to spread out the load and using wider 1.5" straps to up the WLL.
Another important point that we mention above is to spread out the load on the straps by using more of them. When you are using them for tie downs for rafts consider 4 points of contact even for small boats. I used to use two 20’ straps on a 10’ raft because it fits on the racks of my truck, but if one of those breaks then the boat goes flying and could cause the second strap to fail. Ultimately this results in a massive amount of road rash to a $3000+ boat because I didn’t spring for the extra 2 straps at a couple bucks each. Bottom line extra straps = cheap insurance.
Cam straps make poor flip lines. A flip line is another super ubiquitous items for rafters and we use it for all kinds of things. A lot of boaters use flip lines as anchors especially in rescue situations. Again it is important to consider the WLL since cam straps tend to have lower load MBS than tubular webbing (1,500 lbs vs 4000 lbs at 1”)
The previous point also is important when we consider perimeter lines. Perimeter lines on play boats may not need the higher MBS and WLL since they are typically light with with minimal gear / ability to hold water. Larger boats and gear boats can easily weigh between 100-200 lbs with a couple hundred lbs of gear. That alone would a cam strap perimeter line above the WLL, but when you factor in that a 14’ boat can easily accommodate 500 gallons of water and consequently the hydraulic pressure from the river, even the 2000 lbs MBS of the 1.5” strap will snap under a static line trying to unwrap 4000+ LBS of water and gear. We’ll be doing a follow up article on this, but like the adage goes…rig to flip so plan ahead for what could happen.
When transporting gear at highway speeds, on top of the vehicle or on a trailer, when there’s a gap between where the strap goes over two objects, put a twist in the webbing. If you don’t you can get what’s referred to as “strap strum.” Wind passing over the strap can create a vibration in it that, especially on a warm day, can transfer enough energy to where the strap contacts the object that it can melt part of the strap.
When strapping on a frame, have at least two straps on each side attached from the frame to D-rings at opposite angles. This counter-tension prevents the frame from shifting fore and aft. 1” or 1.5” – personal preference. Some orient frame strap ends so they can be tightened from inside the boat and some from outside the boat – personal preference. One neat trick is to girth hitch the strap to a D-ring on the boat so that it stays in place while tightening. Try not to leave any loops or gaps in your rigging that can entrap an arm or leg. For more on this topic you can check out Team Paddler Tony Glassman’s article on How to rig a Cataraft:
If you keep all of these considerations for working load limits for your straps in mind then you will be in good shape. We could write a whole book on stories of strap failures and how spectacularly bad they have gone….maybe in a follow up article. If you have a good story shoot us a message below and let us know your most spectacular strap failure.
