i just bought a used boat, 3500# boat, tandem axle with disc brakes on one axle, i havent towed it home yet but i was wondering. i will be going down a 6 to 7% grade for about 15 miles. this means 2nd gear (auto) about 35 to 45 mph. when i was checking out the trailer i pushed in on the tongue, i was surprised how easy it was. so now i'm invisioning myself towing down a long grade, 2nd gear for engine braking and this trailer is going to have the brakes applied to some extent for 14 or 15 miles. lots of boats are towed up and down this grade without problems but it sure sounds like something is going to get awful hot back there. i get a little edgy when things that aren't supposed to smoke, start smoking! seems like there should be some spring tension in the tongue so the trailer brakes don't come on unless you are pushing on the brake pedal. with this setup it looks like engine braking alone will apply the trailer brakes.