My P35 prop diameter is limited by the aperture to about 13". Boat was converted to a Yanmar 3GM30f from an A4. Transmission
for the Yanmar was the lower numerical geared 2.21 ratio. Prop was 13x12 and seemed just about perfect for the boat/engine/gear ratio.
In a fit of Ebay madness bought a Sailor 13x13 prop. Engine would not go beyond 2800 rpm with lots of smoke with that gearing and the Sailor Prop.. Switched to the higher numerical geared 2.6 transmission at the recommendation of the Sailor people and all is now well with the engine able to run up to the 3600 rpm redline. Listen to the Sailor people if you decide to go with their prop. Using the conventional prop size recommendations for the sailor prop just doesn't work. Anyone want a very low hour Kanzaki
2.21 geared transmission???
Think you are still a sailor so doubt you'd be happy going to a multi blade prop. The prop is very exposed on those boats and any prop drag will be felt in sailing performance.
The Tartan 34C was my first choice for a boat when I began looking to get back into boat ownership
. Unfortunately, they were scarce as hen's teeth on the Left Coast and the one or two that were for sale
were priced higher than what I though they were worth. I'd be happy with a 20hp engine in that boat and think the optional diesel was just a little over 20hp Fairyman. I'm not the kind that likes to pull skiers so don't favor big engines. The 27hp Yanmar pushes my heavier Pearson
just fine and have never had it anywhere near redline, except to test it, in real life use. As you know, was very happy with the 20+ hp Volvo
with a two bladed prop in our 20,000# W32. There seem to be a few smaller diesel take outs from the water
skiing types who want a larger engine so might find a good used engine in the 20hp range. Didn't you buy a used 2 cylinder Volvo
in anticipation of getting back into sailing?? Height is an issue with the engine in the T34C because of it's midship location which may prove an issue in what engine you go for.
If the boat has a wheel
and you want a tiller, make sure they didn't cut off the rudder
shaft extension where the tiller attached after they converted to a wheel
. Most of these boats were tiller steered and only later converted to wheel by idiots.
If you haven't found it yet, there used to be a very active T34C owner's group website. They were very helpful with any questions in my long distance search for a T34C.