Couple things I should be clear about...
A) I launched my 25 foot fin keel boat without unhitching in Spring 2012... the back bumper of my Crew Cab Long bed truck was totally underwater (truck bed filling with water, back doors having water lapping at the door)... My poor truck... But it DID IT! It wasn't the right way though.
B) A Tongue extension (which I had on my Capri 22 trailer) should be extended on flatter ground if possible, then you can back down with it fully extended.. These are a VERY safe way to launch a sailboat (I never needed it with my wing keel 22), my back axle barely got wet.
I CANNOT use a tongue extension though (even if I wanted to modify my existing trailer that does NOT have one). Our ramp has a compound angle... it goes from 15 to 25 degrees JUST before we hit the water backing down.
Want complicated? We cannot raise a mast before we launch. There are trees ALL around our ramp... Want MORE complicated? Our ramp exits about 20 degrees from the paved ramp going down to it... so you back down straight, then turn 20 degrees, to back straight down the ramp.
Pushing on a string? UM... NOT sure what lightweight trailers you folks are using but mine is HEAVY! Probably pushing #1500. It's about as hard to get to sink down the ramp as dropping an anvil. NO WORRIES about it dropping back into the water. Key is get is straight before you back down. You have SOME control over angle it's just delayed when you turn (I am familiar with this feeling with a gooseneck horse trailer).
As for the "winch" I am assuming you folks are talking about a wheel jack or a dolly-jack? The wheels aren't really designed for ROLLING much. Hence the reason I put heavy duty pneumatic casters on my trailer, so it'd roll smoothly down the ramp (I have some tweaking to do to it, but it worked well)...
I am not saying DO what I do. The extensions are the BEST way to do this. If you HAVE to extend the tongue on the ramp... you will need to chock the wheels, and if you aren't sure if the boat is balanced on the trailer (then get a tiltable wheel jack, and mount it on the back of the trailer in case it might tilt. I would not roll back down the ramp with that jack down though. The better solution is to fix the unbalanced situation.
As for boats/trailers ALWAYS having a positive tongue weight... YOU ARE 110% correct! I have seen though, that people transport their sailboat with an outboard on, and some of the larger ones (9.9ish) can really throw off the balance of the boat/trailer (given the distance behind the trailer wheels)... that #85 or so can take you from #200 of positive tongue weight to negative tongue weight instantly. Many owners don't realize the motor mounts/transom isn't designed to hold the motor while towing! I'll also go out FURTHER on a limb... you will HAVE to have that 9.9 on the transom for the launch, so you might have to deal with negative tongue weight then!
For the record I don't launch and retrieve much either... I am just seasonal, but I'd love to have the option of pulling the boat to try out other waters. My goal is to make it so I could haul and go on a long trip with the boat/trailer, and although it'd be a LOT of work, I'd still like to HAVE that option. It's the only reason I am doing my best to design my launching/retrieving/mast raising so that I can do it myself. If I can get people to help I'll always use them. Safety is STILL number 1 priority.
Lubrdink - that's a pretty cool rig. THAT would work on our ramp (looks like you have casters on your extension).
Anyone see one of these used?
Hell Ya Hitch Helper