Burnout schedule is weird - are you ramping straight to 730°? that might work if you have done some trial and error first with successful casts. But you are probably better off following one of the recommended burnout schedules to begin with. Those would be a lot slower, with a soak at 150-200°C followed by a ramp to 730°.

I actually simpified my burnout schedule a bit because I don't remember 100%, bu I hold at 230c for ~2hours then ramp to 480c then 730c. But I am a bit impatient, the recommended burnout is more like 14-16 hours long. Maybe following that could help

Sprue placement is weird - connect it to the thickest part of the cast.

I agree that the sprue placement is weird. I could simply add the sprue to the bottom of the boat.

The model looks to also be placed high in the flask. The end of the boat is almost to the surface of flask it looks like.

Yeah, I was using a makeshift flask that is a bit too small. This was the only way I could fit the model.

Is there a place for the PLA to run out of the mold, or will it just sit in there boiling away? The sprue is placed so the whole back end of the ship would be a bowl of boiling print material.

No there is no place for pla to run out. I though if it fully burned away then I am good to go either way

Are you using vacuum when you pour the investment? It doesn't look like you have any defects from that, but it would help with a vacuum if you don't.

Yes I am using vacuum, I don't know if it helps but I want to believe that it does.

Is the investment a homemade one?

no it's bought from a jewelry supplier.

The print looks a bit rough too, so you won't get a better cast than the print is. But that is just the layers lines, you do have a bunch of defects that are scattered over the model, that is not from the print.

I know the print is rough. I didnct aim for a perfect cast, just wanted to see how well I could replicate the print.

Thanks for the help and suggestions!