A few setup questions for the trailer gurus

[oldrudedude]

1. How much tongue weight should I have on my hitch? I can currently pick up my tongue with one hand and wheel the boat and trailer around the yard. I have not noticed any squirrely handling when towing.

2. Where should my transom sit in relation to the most rear roller/bunk? I have a "transom saver that is designed to slip over the rear roller, but the transom extends about 1" past the roller.

3. With the boat on the trailer and the trailer hitched to the truck, how high should the motor skeg be off the road surface if the motor is in the down position? I also have a bunk trailer. The bunks are adjusted up to the max. It looks like the tilt lock released in transit, for a PO, and the motor skeg ground out on the road.

 

[Knightgang]

Re: A few setup questions for the trailer gurus

1. Your tounge weight should be about 10-15% of the total weight of the boat/trailer combo. If it is light enought, yeah you could move it around. What kind of rig do you have and how much does it way...

2. The last roller should sit under the transom, or at the very least, within an inch of the transom. If you have a keel roller at the rear and can't get the transom saver on it, use the bracket that will attach it to the trailer frame...

3. There is no standard for this. Ideally, you want to be able to lower your engine/outdrive all the way down while trailered, but that does not mean you have the room to tow it that way without scrubbing... On mine, the skeg is only a few inches from the ground when trailer is hoked up. When trailer is jacked up to store, the skeg touches the ground. I never try to tow this while the engine down. Always tilt it up to the tilt locks...

You can fix your skeg with a bolt on replacement if there is enough left. Of you can take it to a fabrication shop and they can weld a new one back on...

 

[Silvertip]

Re: A few setup questions for the trailer gurus

A transom saver should be used as an extra margin of safety if you are relying on the tilt locks to hold the engine up. This is less of a concern if the engine has power tilt/trim, but those without will bounce during transit and those tilt locks are not meant to take that abuse. They can and do break allowing the motor to drop hitting the pavement.

 

[oldrudedude]

Re: A few setup questions for the trailer gurus

Thanks.

The single axle roller trailer hauls a 70ish 14.5 ft runabout and 50hp evinrude. I have never weighed the rig. It feels quite light. I am quite comfortable with the feel of this combo. I have concidered moving the boat forward on the trailer such that the transom sits directly over the rear roller. This would allow me to slip the transom saver over the rear roller. My concern was inadvertantly changing the balance of the rig for the worse. As it is , however, I think i can safely shift the boat an inch or so forward without increasing the tongue weight too much.

The single axle bunk trailer, however, is a different story. It hauls a 16ft deep-V bowrider with a 100hp Johnson. This rig is very heavy on the tongue and I can't do much with it without using the tongue jack. The trailer is over 18ft long, but the bunks are only 67". Over half the length of the boat is unsupported forward of the bunks. There is no crossmember forward of the bunks to install an additional support. Does this look like a normal setup?

 

[Knightgang]

Re: A few setup questions for the trailer gurus

MIne is a similar setup, but there is a keel support under the bow.

 

[oldrudedude]

Re: A few setup questions for the trailer gurus

The tongue weight and lack of support under the lower bow is what concerns me. I have swapped out the old dead 140hp engine for a slightly lighter 100hp. This will put an even greater % of the weight forward of the axle. I am concidering extending the bunks and moving the boat back so the rig is not so tongue heavy. Any comments or other ideas appreciated.

 

[mike343]

Re: A few setup questions for the trailer gurus

I dissent from the 10-15% tongue weight recommendation for boat trailers. My trailer manual, my actuator manual and all the trailer Mfgrs. sites that let you see their manuals all say 5-10%. In my case I tow 5400# plus fuel with barely over 6% tongue weight with a Tahoe. And with about 12,000 mi. of towing with this rig I have never had any sway or pitch or stopping problems.

The 10-15% goes with travel trailers with(for the same weight):
1. Big side cross sections for wind gust loading
2/ Much higher c.g.'s (affects dynamic stability)
3. Generally shorter distances between the hitchballs and the tires.
4. Lower yaw and pitch moments of inertia (sorry, but it affects stability)
5. More aerodynamic drag.

 

[vegasphotoman]

Re: A few setup questions for the trailer gurus

I would put a support under the frt somewhere (other than the bow stop) on your second heavier rig...............

most of the fiberglass bigger boats are too heavy for lifting by hand.....
we have a 14.5 ft fiberglass Glaspar, 75hp johnson, I can lift that by hand.

 

[oldrudedude]

Re: A few setup questions for the trailer gurus

I dissent from the 10-15% tongue weight recommendation for boat trailers. My trailer manual, my actuator manual and all the trailer Mfgrs. sites that let you see their manuals all say 5-10%. In my case I tow 5400# plus fuel with barely over 6% tongue weight with a Tahoe. And with about 12,000 mi. of towing with this rig I have never had any sway or pitch or stopping problems.

The 10-15% goes with travel trailers with(for the same weight):
1. Big side cross sections for wind gust loading
2/ Much higher c.g.'s (affects dynamic stability)
3. Generally shorter distances between the hitchballs and the tires.
4. Lower yaw and pitch moments of inertia (sorry, but it affects stability)
5. More aerodynamic drag.

Good points. Although I have not studied the dynamics of towing, I agree with those concepts. And I have personally noticed when towing a tongue heavy rig with my Ranger pickup the steering and braking feel somewhat less stable due to the change in pitch (attitude) of the vehicle.

I don't know how I could weigh my trailer/boat rig. The only local scale I know of is at the landfill site.

I definitely think I need a lower bow support. I don't understand why the trailer manufacturer did not put one on this assembly. I think I will design a bolt-on member with a shallow V and a roller. Any ideas?