Absolutely…
I think bow and stern ropes tied to the FRAME of the car are essential. As Peter said, it’s all about how comfortable you are with the potential of killing someone if your boat flies off the roof, and to me the hassle of adding 2 extra lines is worth the piece of mind.
Little story:
My best friend is a fellow windsurfer. He had two windsurfing boards on the roof-rack of his Honda Accord (Thule racks). Driving home from Charleston to Myrtle Beach the steel fitting that “clamps” to the sides of the roof fractured and the entire “system” of roof rack, bars, and two windsurfers flew off the car at about 70 mph. The landed in the middle of the highway and as my friend braked and pulled to the side of the road a semi-truck hit the assembly and absolutely disintegrated (sp?) one of the windsurfers. Interestingly, the newest board (I think it was a Pro-Tech) was the one that was completely demolished as it had a relatively thin fiberglass shell and a foam core. His older board, a Mistral Stinger, was thrown to the side of the road and only had a few dings and some road-rash. The truck continued on and didn’t even stop.
The point of the matter is that if the boards had come off with a regular passenger vehicle behind him, the boards and racks could have gone through a window, or made someone swerve into the median…etc…etc…
Trusting that your roof racks “bond” to the roof of the car is putting a bit too much faith into the system for me. You have no back-up and basically have 100% faith that the fittings will never fail…
I think it’s one thing to risk your own life by not wearing a PFD, or running water that is beyond your ability…etc…but by not double-securing the boats I feel like I’d be risking someone elses life…
Just my opinion though…other’s experiences may vary 
BeachAV8R
Tie-down loops are great!
Mine are strong nylon strap loops about 6" long that are easily bolted under the hood. Got them from Spring Creek Outfitters for about $10 including shipping. I like them because I don’t have to crawl under my vehicle to secure the bow tie-downs. When I’m not using them I open the hood, flip them back inside, then close the hood.
Hey
Another reason why you shouldn’t talk on the cell phone while driving eh! Some people are so oblivious eh?
Yep, that’s why I feel
one needs front and rear tie downs. I know that the rack has more of a chance coming loose than my bumpers where the lines are tied. And for some reason my hulley rollers don’t offer much in the way of sideway stability when I turn a corner.
My yak is 16 ft long. The distance between each bar on the rack is not even half of that, before I put on a shell and spaced 'em out, it was worse.
Jim
Thanks for the link! I’m going to order some of those cinch tiedowns for my QCC-they’ll give me some peace of mind when travelling at high speeds! Now all I have to worry about is my rack falling apart! Never thought of that one!
Bow and Stern lines
My .02
I installed U bolts under the front of both the mini van and car. I use clips on the end of the lines and secure loosely with the " great " truckers not. No crawling under the vehicle anymore. I’ve not had any problems and like the security the two lines provide.
I have Yakama racks and saddles on the van. The Cruiser has factory racks and Thule J saddles.
What ever system you choose, IMHO it is well worth the few minutes it takes to use.
Joe3
Way to go Linda
I was having nightmares involving flying Canadian QCC’s
Jim
Nope
Don’t need to check oil and change regularly. Tires don’t have tread, so what? How’s that saying go? Stupid is as stupid does.
Ya I could just see it now…
I wouldn’t have to worry about anyone helping me lift my kayak off the rack- it would just go flying into the water! On second thoughts… maybe I shouldn’t get those straps! HAHA! No more lifting!
Another Story
Met a real nice person at New Year’s paddle who told me a story of his Eddyline Falcon that came flying off the roof along with his racks causing some serious damage. It convinced me to always use a bow, stern, and belly line. I’d rather learn from other people’s mistakes. Perhaps it’s unlikely to happen, but as I see it, if it happens often enough for me to meet a victim, that’s good enough for me.
Lou
Use 'em!
The front and rear tie-downs are probably the quickest part of loading up for me. I tie them into the towing loops on my Volkswagen. When I’m paddling, I untie the trucker’s hitch and tuck the lines underneath the car. Very solid - and I do it even in town.
These racks are made for weight, not lift. A kayak going down the road doesn’t weigh anything - it’s producing lift, trying to pull itself off the roof. Put a bow line on and there’s lots of strong leverage there.
Plastic Verus Composite
With a short plastic boat like the Mars I just pull the straps down real tight. I thread the straps thru the scupper holes, so they are not going anywhere.
Kevlar or fiberglass won’t give like that and it takes alot more to keep them on top of the vehicle. I use bow and stern tie downs for the 18’ kevlar Shearwater.
BTW: Check those straps if it rains! They get lose if they are wet!
thanks for feedback
Thanks for all the thoughful comments. Front and rear tiedowns will become part of the routine. The thought provoking comments were about the possibility of a failure of part of the rack assembly along with the risk of injuring someone else. 'nuff said.
Web Straps versus line (rope)
Linda, webbing will flutter at speed and produce lots of noise. Lousy in my opinion for front and rear tie-downs, great for strapping the boat to the rack. Some folks put up with it. Some folks wrap it or wind it to create a “roundness” to it so the flatness will go away. I suggest you look into just using line and learn the truckers hitch or use the line cinching pulleys. Just FYI.
Even on our trailer
I almost lost a friends CD Extreme off of our trailer one time because of what he claims was a strap failure (his straps). Now I always attach a somewhat loose bow line to each boat that runs to the trailer tongue. A third point of attachment always a good idea.
Well, then you have a good…
insurance claim & get a new boat. Start using all that insurance money you have paid for. I have paid “thousands of dollars” over the past 17 years of driving & have only used $600 of it. Just think of what I could’ve bought.
Paddle easy,
Coffee
Coffee
Eddyline doesn’t make the Calyspo anymore. That’s my baby. I’d rather see an entire cargo ship full of good beer sink in the Gulf of Alaska, then watch her fly off my roof.
This is worth a read
Im not sure what the right answer is. I always base mine on distance and mph to the put in. But, I sometimes do, sometimes don’t tie down four points (2 over, 1 front, 1 rear).
But here’s a true story to consider your dilemma. I had a guy show up late to my livery one day last summer. His friend had been waiting here about an hour for this guy. We finally got a phone call from him telling us he would be here in 20 minutes.
At last he arrives, and the rack on his minivan is twisted like a pretzl. Kayak resting in between the bent frame of the rack, and yes, now tied down to the front and rear of the van.
He chocked up the reason he was late, but didn’t even need to when we saw his ride. But a wind gust caught him at 45 degress or so as he was traveling 70 mph, and cleaned the kayak off the rack. Skipped down the highway a few times. NO injuries or such, just a humbling experience. God bless plastics I guess. Boat had some scratches, but lived to see another paddle. That boy was lucky in many, many ways.
Sherpa
uhh Coffee,
… nevermind.
The problem
I see with relying on just the factory rack, or any that's attached to it, is what I will call the "hanger factor."
As you travel, the canoe or kayak will move up and down and so will the rack.
Many have taken a hanger and bent it back & forth until it weakens at which point it easily breaks.
The same is happening with the metal on the roof around the fasteners and if I did only rely on this to hold my equipment up there I would check these areas on a regular basis for stress cracks.
I still wouldn't trust it though, but that's just me.
As I mentioned earlier, I work in the auto industry on the quality side of things so I know that all metal isn't created equal, not even if it's from the same supplier and was produced on the same machinery, even on the same day.
I do know that when I wasn't using a stern rope my factory rack fasteners back there keep working loose, but since I have, I've never had a problem with this issue, which told me something.
Even though I use both bow & stern lines, in addition to the two belly straps, I still get up there and check to make sure everything is tight about once a year just to be on the safe side.
Jack