I thought about a bucket-like device, but I opted for a Garhauer Lifting Davit instead. Gene Robert's documentation on the installation by Myron Spaudling in the Association manual is excellent. I have provided photos and some text related to my installation of the davit on my Ariel web page,

http://www.solopublications.com/sailarip.htm

Although the bucket might be a fine idea, you have to pull the motor once in awhile for maintenance etc.

What I found intriguing about the bucket idea is that you could slip the bucket in place, pump out the salt water, and then fill with fresh water for flushing, and finally pump out again for long term verticle storage. However, if you have a long shaft motor, that would be one deep bucket.