I have watched a number of videos on you tube when it comes to strapping a kayak to the crossbars on the top of your vehicle.  In the videos I have seen, they run a kayak strap from one side to another per cross bar.  So two straps.

 

I don't see anyone show/mention tying the front and rear down to a hitch/frame under the bumpers of the vehicle.

 

Are the two straps that go from left to right enough to hold it in place?  

There’s always a chance your straps or rack fail in some way and your kayak will go flying putting others in danger. Takes a couple more minutes to use bow and stern straps, better to be safe than sorry.

42 minutes ago, crankbait2009 said:

Are the two straps that go from left to right enough to hold it in place? 

That would really depend on how far your going, how fast you drive, and of course how paranoid you are that it'll fall off. I'd be the paranoid guy that took the time to add the extra front and rear straps just in case.

makes sense to me.  thanks for the input

For awhile I had a 14 foot and a 10 foot kayak that I car topped only needed to tie the ends to the bumpers on the 10 foot yak. I used cam buckles not ratchet straps on the load bars. Long trips I would stop and check once in awhile to be sure everything was tight.

I've got a 10ft as well

I recommend using the front and rear straps. Its a simple task to prevent a potential disaster.

 

How much strain can you put on the front and rear handles before it's too much?  Those handles are my only tie down spots at the front and rear.  Always read you don;t want to use them as anchor points.  is that a true statement?

8 hours ago, crankbait2009 said:

I've got a 10ft as well

I meant to say the 14 footer was tied at both ends.

it really depends on how wide apart your crossbars are in relation to the kayak.  General rule of thumb i follow is you want at least 1/3 of the length of the boat between the crossbars.  If this is true, then the bow and stern straps aren't needed.  You also have to consider that bow and stern tie downs are not really going to help if your rack fails as slack will be introduced to the system and it will most likely fall off anyways.  

Bottom line is do what you feel safe with and if you feel better using the bow and stern tie downs then by all means do it.  

Bow and stern lines are mandatory in my book. If a camlock strap fails they are your only backup. Consider your investment that is sitting on your roof. It's worth the extra couple of minutes to secure it properly. Even more important, consider the possible consequences if straps fail and your yak becomes a missile while you're on the road and it targets a following vehicle....

 

https://paddling.com/learn/kayak-rack-fail/

Agreed on the bow and stern lines. I have transported kayaks a bunch, and multiple at a time as that’s what we use freediving. Safety safety safety, for you and others on the roadway. Attaching to the handles isn’t perfect but better than nothing. The bow and stern lines are there for an emergency if something were to happen with your straps your using to keep the yak on the cross members. If they fail the kayak will fall onto the side of the vehicle but not tumble down the freeway due to the bow/stern lines holding it. Gonna cause some damage but everyone walks away.

can you recommend a strap that is best used at the bow/stern handle locations?  I'm assuming ratchet straps are best to use at these locations?

Ratchet straps are in the "Book of No" pertaining to kayaks (generally speaking). People all too often crank them down too tight and run the risk of damaging the hull. Use something similar to these...

I use cam locks all the time for transporting my kayak.  But until this season, I never had to haul it on top of my vehicle.  I plan on using the camlocks for the crossbars.

 

1. what are those?

2. How do you tighten them as needed, without undoing the knot every time?

After transporting a number of different kayaks in a number of different rooftop configurations over thousands of miles, I would say that it depends.

However,  I will say that even with my most confident load, I have put bow/stern 'insurance' straps, like those above, when travelling over a couple hundred miles each way.

My current Hobie load configuration,  I use them every time.   I transport upside down now, and there is more risk of fore/aft slipping then I ever had in the past.

There is a small lever that allows the rope to release the tension. To tighten, set the hooks in place and pull on the tag end. Similar products can be found at Tractor Supply. These might be cheaper but the rope length might be too short. Easy to replace the rope....

4 minutes ago, crankbait2009 said:

I use cam locks all the time for transporting my kayak.  But until this season, I never had to haul it on top of my vehicle.  I plan on using the camlocks for the crossbars.

 

1. what are those?

2. How do you tighten them as needed, without undoing the knot every time?

Funny...they are a ratchet mechanism

At least mine are that look identical...you can release the ratchet without untying anything 

that black thing on the right was throwing me off.

thanks for explaining.

Yep, technically it's a ratcheting mechanism. The difference is that a ratchet strap allows additional leverage and can be cranked too tight. I'm sure if you were hell bent on causing damage with the rope lines you could if you worked hard enough but would require a lot more effort.

Another item not to forget is a red flag on the rear of the yak. It might be required by law if the yak hangs past the end of your vehicle.....

interesting.  I found those.  They are called "rope lock tie downs".  Who would have thought.  I only ever seen/used the straps.

 

https://www.amazon.com/dp/B07D2B94D2/ref=sspa_dk_detail_1?psc=1&pd_rd_i=B07D2B94D2&pd_rd_w=xakW8&pf_rd_p=80559f3c-f83b-49c1-8a72-40f936e9df7a&pd_rd_wg=OeerD&pf_rd_r=Q2X3E194FV4FG71N78PS&pd_rd_r=724cd6bd-3917-11e9-9811-274d63e66d10

The 3/8" version is a bit overkill. You could get easily use the 1/4" size. I'm using the 1/8" with paracord. The beauty of using the rope is that it greatly reduces wind flap. Webbing flaps a lot and can drive you crazy....

I got a pair with each of a couple different Thule racks.  You can get Thules ratchet ropes separate, but it will cost you

Those are what I used when car topping any boat over 13' on my car.  Flat cam-lock straps vibrate annoyingly, even when adding a twist when used to secure the bow and stern.  The rope style don't vibrate, and are super easy to use.

A little rope and a trucker's hitch work just fine. Hauled an old 15' aluminum canoe on suv rack for hundreds of miles.