Replacing a Volvo Penta MD2B

[stanirish]

I've decided to replace my md2b that is hooked to a hydraulic drive. The engine has been rebuilt several times and time for a change. It will make a good garage project...

I want to keep the hydraulic drive that's in the boat. I'd like to get a new or newer smaller diesel (15 to 20hp) that will fit the hydraulic drive. I'm not that familiar with hydraulic drives, I'm researching. It works well. I don't have pictures of the drive part that is attached to the propeller shaft, I should have included. I'm thinking that a new engine hooks up to either a gear transmission or a hydraulic one? Any wisdom on this is greatly appreciated.see photos

[Pete7]

What is so special about the hydraulic drive that you want to keep it over say a normal gearbox and shaft?

Pete

[stanirish]

Pete, In the upper left pic the toolbox tray is lying on the drive that is attached to the propeller-the hydraulic pipes are under the flooring from the engine to the drive. The shaft and drive work well and I want to keep costs down by hopefully only having to just replace the engine. These hydraulic drives where popular at one time in these sailboats.
The engine flywheel faces the drive-interesting setup to say the least.