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The sad part is the folks in the opposing lane seemed to have paid the biggest price.

Folks, please make sure your tongue weight is at least 10% or more of the total towed weight. That's what prevents this.

Also pay strict attention to the rated tow weight of your vehicle. This unfortunate incident involved a VW Vanagon way in excess of its design limits.
http://www.gowesty.com/library_article.php?id=604

kmclemore wrote:The sad part is the folks in the opposing lane seemed to have paid the biggest price.

Folks, please make sure your tongue weight is at least 10% or more of the total towed weight. That's what prevents this.

I agree that 10% is safe - but as an owner of a European car often used for towing, a Volvo wagon, it appears European cars are designed for 5% tongue weight. That is why I originally installed the 2nd axle stabilize the trailer.

Uff, I fell this my first time towing the boat (really scary) , I have a 2 axle trailer, I thought the problem was the 2 axle (first time with one with 2) and off course the speed, I was driving a 100/110 km/hr.... After that I reduce it and never happen again. The car was a ford explorer.

Interesting to know that the solution is to have more weight in the tonge, ideas to verify this? (well if boat+trailer = 1000, 10% = 100, means hard to lift by hand)

Regards

peterix wrote:Interesting to know that the solution is to have more weight in the tongue, ideas to verify this? (well if boat+trailer = 1000, 10% = 100, means hard to lift by hand)

Set the trailer frame to the same pitch (off-level) as it is when it's on the tow vehicle with the vehicle suspension sagged (or not) as it normally is by measuring some reference point to the ground when it's on the vehicle, then duplicate that without the vehicle there. Then put a bathroom scale under the coupler, crank up the tongue just a little, and put a 2-by under the coupler on end (cut to the length needed) and lower the coupler so the 2-by is taking the whole tongue load to the scale (you might want to put another short 2-by on the flat, to distribute the load over the scale surface). Don't worry about the stability of the 2-by; as long as the trailer wheels are blocked and the jack is retracted just enough to remove the load, it's not going anywhere. What the scale shows is the tongue weight. It's important that it be on level ground and in the orientation (level, or however far out of level the frame rails normally are) it's in when actually towing - bow high or low will change the amount of load on that coupler, which can be complicated by two independent axles (torsion suspension).

If the tongue weight is too high for the scale, put a short 2-by laying flat, or better, a short length of pipe, on the scale, and stack whatever else you need (2-bys, bricks, short length of pipe) a couple of feet away to bring the two horizontal pipes (fulcrums) to the same elevation, than lay a 2-by (or a 4-by) across the two pipes. Put the coupler over the exact center of the span of the 2- or 4-by and lower the load onto it. What you read is half the actual tongue weight.

Another reason to always check to see that the boat is all the way forward into the bumper. Just a little way back and this balance is all screwed up. Personally, I like to shoot for 20% on the tongue. That way I have some leeway in boat contents or loading. Sort of extra margin for error.
Dave

Thanks, and right, is easy to measure, to correct it (assuming I have less weight than correct) I need to allow the boat arrive more forward, maybe a little adjustement of contact point.

boat is over 350 pounds on the hitch. Too heavy? It does not make my tow vehicle suspension move even a centimeter when I drop the hitch on the rear of the tow vehicle so I though the weight was okay - is it too heavy?

BOAT wrote:boat is over 350 pounds on the hitch. Too heavy?

Being that the gross trailer weight is probably something over 4000 lb, it's a bit light if anything. But if it tows stable, then no further action is required, IMO.

You also have a tow beast, which certainly helps.

Just wondering - my Volvo XC60 has, in the service manual, a rated tongue weight of 165lbs. However, the factory tow package for this vehicle has very explicitly rated the tongue weight as 350lbs. Is max tongue weight typically related to the actual tow hardware (the tongue, ball, etc) or is is typically related to the mounting points on the vehicle?

Towing capacity and tongue weight is based primarily on the suspension and tires, and secondarily on capacity of the drivetrain. The basic XC60 has the lower capacity. Tow packages typically add one or several of the following: Beefed up rear suspension (increased capacity springs, struts), towbar and wiring (and in case of your Volvo, programming added for the wiring), additional capacity on the transmission cooler, and in the case of a real tow vehicle like my F150 (that took over towing from my XC70) additional trailer sway control built into the vehicle stability system.
While towbars are rated for specific capacities, it is not likely your towbar is the limiting factor.

And BTW, your tires are probably one of the most limiting factors on towing capacity.

The towing capacity, depending on where you read, is either 3300lbs or 3500lbs on the XC60. Its marginal but acceptable IMO for short towing an that is lightly loaded. I certainly wont be doing any mountain driving, and will probably stay at 90 km/h in the right lane. How did you find the XC70? Slightly longer wheelbase but otherwise I would suspect pretty similar to XC60. I actually think the rear overhang on the XC70 is fairly longer than on the XC60 which would counteract any wheelbase advantages.

The tow package included reprogramming for 4 pin wiring, different transmission settings, and to integrate into the vehicle stability control (http://www.swedespeed.com/news/publish/ ... _1550.html). It specifically did not include a transmission cooler (Volvo indicated there is no OEM cooler) and I don't believe the suspension was modified in any way.

I'll probably try to set the tongue weight around 250 - per Mac manual recommendations and it pretty much splits the difference between the XC60 user manual and the tow package literature. I'm actually planning to tow it for the first

Your transmission is probably already cooled in the radiator. Suggest if you have surge brakes to add a wire tap to your reverse lights and run a 5-pin trailer harness so you can back up without using the lockout key on the trailer coupler.
The XC70 was real good towing after I added the second axle. I was real sensitive about tongue weight since the car is rated for 5% tongue weight. We usually drove two cars so no one sat in the rear seat in order to control weight on the rear suspension since I exceeded the rated tongue weight.
I used the factory hitch that integrates well into the body mounting.
The turbo is great for power and the AWD pulls the trailer right up the ramp.
Reason I stopped towing is that Volvo uses a really expensive transmission. Mine kind of blew up - not sure if it was due to towing. Also, found that the splines on the bevel gear (the gear that directs power to the rear wheels) were nearly stripped and this part is about $2k US. So, while a really good tow vehicle, the weak point is the bevel gear and transmission.
BTW, I also learned that salt water does not like the parking brake. Besides the parking brake pads corroding (and good luck flushing these), the salt water gets into the parking brake cables and will seize these up. These are kind of fun to replace So if you can, pick a steep ramp where you can float the boat off the trailer without getting the rear brakes wet.
As far as what tow weight works - it is really up to how many axles you have, how the boat and car are loaded, and how fast you go. It was fun the one time I learned that the brake fitting used on the Mac trailer are really inferior and easy to break - and I hit standstill traffic on the highway on a curve without trailer brakes - Volvo really has good brakes

For sure the Volvo with the turbo feels like its barely breaking a sweat on the launch ramp - lots of beefy torque. I'm freshwater only so no concerns about the salt.

I am strongly considering a dual axle trailer - the problem is that the whole thing is around max towing of 3500lbs with the 700 lb factory trailer, and most dual axle trailers seem to be 500-600 lbs heavier. If you know of a source for a lightweight aluminum dual axle (700-800 lbs maybe) I would get one in a heartbeat.