Man, it's a good question that could inherit long answers and possibly a heated debate
I'd just like to say firstly, that these are my opinions on what you should do
My horse right now will pull a log, and it took some long training. There are so many factors that have to be taken into consideration. First, imagine that you were the horse having to pull the log. You would have someone on top of you that is in possession of a rope, that is pulling something fairly heavy. You can imagine that the log, while it is being pulled along behind your horse, is going to make some noise. Some serious noise. Now, for the duration of the ride, he is going to have this "noise" following him. When he stops, it stops, when he goes, it goes. NOW (sigh
), while you are doing the work with him, take that into great consideration.
The way I first approached the pulling of an object with my horse, was to pick the object... -_- I wanted to gradually bring him into the realm of noisy items, so I picked something that was going to be quieter. I picked one of those blue water jugs (you know... the one's for camping). I kept the top on so none of the vibrations would cause too much of a noise. Then I tied a very long rop to the handle, and I was ready.
With things that I know
, or even think could freak my horse out, I always
start with groundwork. First I let him see the jug, sniff it paw at it (whatever he wanted really). Then I would gradually put the jug on the ground and start very slowly circling him with it dragging on the ground. Depending on what his reaction is, you can proceed so forth, either with getting him more comfortable with it, or proceed to the next step of having it follow behind him. This could be very traumatizing for a horse, so tread carefully. I think you can understand the steps after this, such as pulling something heavier, getting on your horse to pull something ect. Just proceed to the next step, only after he is bulletproof (so to speak
) with the step before.
As for tying the rope to the saddle horn, I personally think it's dangerous, because horses do unexpected things, and I would rather be able to cut/let the log off my horse at a time of urgency. I actually hold the rope in my hand if the item is not too heavy ( I know... You're probably rolling your eyes, and if your horse is calm, you could probably use the horn, just have a knife handy if things go badly :))
Hope I helped, and all the luck to you!