Hello Ray,
I suspect that you will find that the cost and complications of an inboard engine, gearbox, shaft, propeller, controls etc, etc, are disproportionate to the value of your boat.
You might find this recent topic on the SS27/P27 section useful...
Outboard v Inboard:
http://www.parkerseal.or.../topic.asp?TOPIC_ID=1325
I don't know what you have fitted at present, and whether it is on the transom or in a well, but I had a Seal 22 a long time ago with an outboard in a well - I forget exactly what was fitted when I bought it, but I replaced it with a Longshaft 7.5hp, changed the standard propellor for the largest diameter, smallest pitch, one available, and could reach maximum hull speed at cruising rpm, and had perfectly good stopping power and reverse thrust.
If your engine is mounted on the transom, any of today's outboard manufacturers' extra long shaft "sailing yacht auxiliary" models between 6hp & 8hp will do an even better job; this is because the extra long shaft puts the propellor deeper in the water where it gets more "bite" &so can exert more thrust, whilst staying immersed when eh boat is pitching.
, whilst their exhaust systems and propellors are specifically adapted to the needs of a yacht auxilary.
Geoff Sheddick
Parker 27/146 "Stroller'
Geoff Sheddick
Parker 27/146 "Stroller'