Not sure of your location but we lived in WA for 20 years and all river based yachts tend to get set up able to drop their masts to exit the Swan River. So masts had hinges built in at deck level. Assume your is the same?
Most use similar set ups to control the lowering - two equal length spinnaker poles, some kind of fitting to clip the the two poles, a block and tackle, and the forestay together, and two side deck or toe rail rings to clip the poles into - allowing them to form an A frame.
The block and tackle are attached to that pole end fitting and the forwstay deck point.
Then it's remove the boom (especially on a big rig), off with the backstay, on with a masthead halliard led forward to slacken the forestay , unclip that and attach to the two poles, and begin easing on the block and tackle to see the A frame rise up, and the mast come down.
A couple of wooden crosstrees made long enough to stop the mast swaying off centre once the mast is back and the stays are slack, will alllow you to motor with some degree of comfort - but the risk is passing waves or wash might lead to the unstayed mast swinging out side to side - and snapping.
We had a 40 foot Adams with around a 55 foot rig and found we could do it with the two of us on a regular basis. Does help build your muscles as grinding it all back up after usually takes some effort.
Oh - about ten years back one local sailmaker came up with what he called a 'mast skate' - and we did get involved in its design etc.
Twas a stainless item with four large rollers (just like a roller skate) and a stainless sail slug between them. One took off the sail and fed this device up the sail track with the sail slug holding it forward, and the wheels runing on the back side of the mast. The two poles were fitted to rings set aft on the boat and clipped to this device. As one then hauled this device up the mast by the main halliard, once the forestay and hinge were let off, the mast sarted to come back. Once moving, one needed to strongly control a downhaul on the device - as gravity takes over.
To get it all back up - you simply haul the device back down along the mast, and it lifts the rig.
The big advantage of this innovation is that all the time during lowering and raising, the mast is supported so risk of loss minimised.
If you want his name and some general detail on how to find him - send me an email. firstname.lastname@example.org