Hopefully I can add some words of wisdom. I have been trailering large trailers (relative to a 3/4 or 1 ton tow vehicle) and tow our 27 footer which tips the scales at 8,500 lbs on the trailer axles, plus another 800 or a 1000 on the tongue. I also have built all my trailers from scratch or modifications of older trailers. I also spent three years of my life driving OTR in a conventional semi-truck at 80k, 13-5 high and 85 feet long. All together I have about 2.6 million miles. So hopefully this all counts as having some credibility. Eventually I too plan to replace our 27 ft, 8 ft beam Buccaneer with a a 31 ft or so up to 11,000 lb sailboat. Thats about as much as a good heavy 1 & 1/2 ton tow vehicle can do Above that a small semi tractor and a real boat hauler trailer. I tow my 27 ft with a heavy rated 3/4 ton. See the posting titled “Out to Inboard Conversion and Boat story” for the history and mods I’m doing or did to our boat.
You have not mentioned anything about the capacities of your trailer, AND just as importantly… your TOW vehicle.
So I will express my observations over the past 30 years and 2.6 million miles. Not so much for you as it sounds like you have pulled some, but for the rest of the boating public.
#1 When you tow… you really don’t “drive” the tow vehicle…. you “drive” the trailer. The tow vehicle is just the means to do so. Think about that a minute. Doesn’t matter if its a 16ft hobby cat or a 53′ x 102″ wide semi- trailer. You drive the trailer. Everything you do… you do for the trailer.
#1) DO NOT tow anything outside your tow vehicles design capacities. Take the CGVW and reduce it by not less than 10% if you plan on hills. 20% for the hills in TN, WV, and KY and the rockies. I have seen a lot of wrecks from over loaded-over pulling 1/2 tons. A half ton is not designed to pull over about 5k and thats really pushing it in my mind. For bigger boats and your 30 footer a good heavy rated 1 ton (not the standard rated) is the minimum and really wants more.
#1) BRAKES BRAKES BRAKES, I repeat BRAKES BRAKES BRAKES!!!! You do not say what type and how many axles your trailer has and how many axles have brakes incorporated. Since you have pulled others I imagine you have been “pushed” every now and then on an emergency stop. Anit-lock brakes make it even worse in my mind. Your anti-lock system is in the ball of you right foot. Remember… YOU control EVERYTHING that vehicles does… not the other way around… EVER!
If you vehicle is ever out of control.. that means YOU let it (with one exception due to others and the laws of physics).
Where it comes to brakes…. you can never have too much. Always keep them in 100% order. I MEAN this. Many people do the “is only a few miles… I’ll just use the truck’s brakes for now” and fix the trailer later. A VERY BAD practice, although I have been guilty on a couple of times myself.
Many light duty trailers (meaning anything non industrial) only brake one axle on a tandem, two on a triple. Some say thats by design for slippery conditions (so the trailer doesn’t slide out side ways as easy)… well, to a point. I personally want brakes on all axles, with one axle switchable to off on my command (not hard to wire in). ALSO, ANY 10k+ trailer behind a 1 ton is NOT a winter road rig with a tow behind trailer. NEVER will be. A properly set up fifth wheel will do better, but in either case its better to park and wait. You have no other real options. (Keep in mind I ran the north route from Minneapolis/St Paul to either LA or the Bay almost every week for three years. I’m from snow country and have ran snow as much as 1500 miles at a time…. BUT, my semi was set up for it. By default I still keep all my vehicles set up for snow… even here in southwestern OH, where in my mind we really do not have a winter proper… just a perpetual fall.
#1 TIRES, TIRES, TIRES… yes my other pet peave. Towing anything bigger than a simple runabout or small sail boat really needs load range E stiff side walled tires. I was surprised to learn how many people do not understand load range. Load range C conventional 1/2 ton (or its equivelent sport utility) tires have way too much side wall flex for good trailering and control. Yes, an 80 psi Load range E will let you know if you ran over a dime or a nickel, but will handle and drive much much more stable under a load or with a load behind it. If everything is set up proper… she”ll drive straight down the road. Overloaded C’s will wonder all over the place and you’ll be cussing them in a heartbeat. Fighting any vehicle is tiring and dangerous.
#1 WEIGHT and BALANCE. This is another subject very few have any good handle on it seems. It is especially true with conventional tow behind hitches. Think of it as two see-saws connected end to end. Place weight at any point or end of one of the see-saws and it effects the other.
The standard rule of thumb is to carry 10% of the trailer weight on the tongue/hitch. This is important! A tail heavy trailer will want to push you around, AND CAN GET OUT OF THE TOW VEHICLES ABILITY TO CONTOL in a heart beat. It has to do with physics and the dynamics of a mass in motion. Its complicated calculations, but suffice it to say it IMPERATIVE to maintain this rule!. Hitch stabilizers will help… but only to a point. Too much on the tongue and you lighten the front end. Remember, for every lb you place behind the rear axle a portion of that is removed from the front. KNOW your trailer’s center of gravity and balance it to the 10% rule accordingly.
Partially related to this is the relationship between the bridge length of the trailer and the wheel base of the tow vehicle. The “bridge” is the length from your pivot point (hitch in this case) to the center of your trailer’s axle or group of axles. The longer the better for handling and backing… up to a point. The rule of thumb is that you ideally want your bridge to be not less than 1.25 times the tow vehicle’s wheel base. Not always possible, but trailers that conform to this will handle, tow, and back better.
#1 vertical stability
For your situation being 13 ft high is not typical for this trailer type and I’ll add my thought to this as well. As you say about 1/3 of the boat’s weight is in the keel… but its only a third. Don’t forget that. You will be top heavy to some degree. Curves marked with a speed will MEAN it for you. The trailer’s design and capacity will have an effect on this too. If you’ve maxed out or exceeded your trailer’s suspension capacity she will lean much more that if some extra capacity was still there. It was for this reason that I went with a triple axle group and a 30% over capacity on the springs. When your building from scratch its easy to incorporate extra capacity than to change it later. You do not mention what you have, but you might want to look at these numbers. Any extra capacity in the trailer’s suspension will add to the vertical stability factor. If its conventional springs, they’re fairly easy to change out. If you’ve a torsion suspension system… I’m not sure. Might one would have to get total different axles depending on how it was designed.
As far as being 13 ft per se. That really no problem. Standard Van type semi trailer’s are designed around the 13′-4″ mark. Plan you routes. You will actually already be planned/routed when you get your over-width permit. Let them now your 13 high and they will route you away from any low overpasses. But keep your eyes open and do not believe the clearance signs. They can easily be a few inches off from resurfacing below them. If I were you, anything less than 13-6 on an overpass I’d not been under before, would require me to inch my way under it observing the entire time. Also overpasses that have anything but a level strailt surface will effect your relative height. Not often but I have see where they measure the entrance, but forgot the fact that the other end is rising… you’ll be higher in the middle then due to the trailer’s bridge. the longer the bride the worse this error. I’ve seen it several times. Traffic will wait… they wont have a choice. I’ve done it many times when I was 13-5. Trust no ones directions… they will try bring you under a 12 foot bridge for sure, since generally they never had a reason to really look at it.
Yes, there are all #1 for a reason!