Before I comment I would like to offer this disclaimer: I have never worked on a marine engine, I have only recently gleened an interest in watercraft but I am an avid automobile enthusiast. At the very least have someone verify the following. I am only offering this to help because I do know quite a bit about turbos and all engines operate in the same basic manner.
That being said here's what I would assume/deduce in your situation.
Any engine built from the factory with a turbo is engineered with certain chateristics to deal with the turbo's additional psi. Physically this usually means higher quality parts to deal with the added pressure the turbo creates, as far as that goes it's a plus for you.
On the other hand, the engine is designed to run with the turbos added PSI. The engine will be running rich now that the turbo is gone. If you don't care about the loss of fuel economy I would think you would be alright on such a small engine. Another consideration is that most diesel engines simply compress air untill it's hot, then add fuel so it burns. Once agian, your engine will be designed to compress the air from the "intake" plus the additional air that the turbo would have compressed to reach firing temperature. If you feel that it is running fine, roll with it.
The only notes of caution I would offer you are the following.
1. Be sure who ever disabled the turbo did it correctly. Turbos are generally powered by exhaust fumes, if some jackass unhooked the turbo incorrectly you run the risk of building up exhaust fumes where they shouldn't be which is a fire risk.(especially considering the fact that your engine is running rich, your exhaust fumes are extra volatile)
2. It is possible (and probable) that the timing of the valves is slightly more aggressive than an engine w/o the turbo to maximize the efficency of the turbo, if this is the case at least you will have further decreased efficency, at worst you could ruin the engine. It's unlikely it's that bad, but if it is, you would deffinately be able to tell. It would run bad.
3. Turbos DO BLOW, BREAK UP, AND GET SUCKED BACK INTO THE ENGINE. You need to know if this happened. Drain the oil, get a magnet or something and see if you have metal particles in your oil. Take off the turbo, look at the blades, or make the person who disabled it instead of fixing it do it.
If it were me? I'd use this as a point to knock cash off the boat, change the oil twice over a short period, and ride it until I could fix the turbo. Chances are if the boat has ridden that far without any crazy problems, then all you need is to change the oil just in case.
Anyone want to add or adjust that feel free. I am only offering what I know in an attempt to help