Neil
I to plan to launch my commander from a trailer I had built. I should tell you that I have not done so yet because I am in the middle of a refit. However my trailer was built by the guys at Sail Trailer in Georgia and these guys launch and retrieve boats like ours all the time from the trailer they build. The things they suggested I do which I did to make the trailer work for ramp launching were as follows.
1.) I had a 20' tongue extension built. This extension has a small axle with two wheels and a ball hitch on one end and a coupler on the other. The axle and wheels keep the trailer tongue from dropping down when using the extension.
2.) In addition to the 6 adjustable pad supports that support the hull there is also located at the waterline a v-shaped support that keeps the boat from going too far forward and supports the bow.
3.) I have two keel guides that start up high on the aft most pad supports and slope down as they go forward to guide the keel onto the trailer.
4.) I had a combination adjustable mast support and winch support made that sits on the front of the trailer that has ladder rungs on it to get to the winch.
5.) I had skid brackets made that bolt to the bottom of the trailer frame and sit just in front of the forward axle. If the trailer falls off the end of the ramp these skid plates allow the trailer to be pulled back up onto the ramp without dislodging the axle.
6.) I had them use drop down axles that allowed the boat to sit closer to the pavement which would allow launching and retrieving in less water depth.
As far as water depth needed to launch and retrieve in I'm told it is best if I can use a ramp that is approx. 1 foot deeper than the distance from the pavement to the waterline when the boat is on the trailer. In my case that dimension is 65". So for me the ramp should be 77" deep where my forward axle sits on it. And that is why the 20' long extension.
Hope this helps.
JERRY CARPENTER - C147
A man can succeed at almost anything for which he has unlimited enthusiam.