My boat is a centerboard and as I try to lift the board in the cabin with all my might the shackle breaks on the post leaving the only way to pull up the centerboard being direct up vertical. Wasn't going to happen. Great start.
So there I am direct under the bridge at 3000 RPM NOT MOVING. sitting still. I see other boats motoring through all around me, sailing included. I call a sail boat on channel 9 and find out the current is 1.5 knots at least and I will not make it through the bridge until the tide falls.
First off, fix your centerboard shackle. This could possibly easily be fixed by you, with a wrench, a mask, fins and a snorkle.
Second, are you saying that your engine will not power you against a 1.5kt current?
Your bottom must look like a welcome mat. While you're in the water, after you fix the centerboard, scrub the bottom and the prop with a putty knife, and then a stiff nylon brush. You should be able to make headway of at least
4 kts with the motor.
The vessel should be in the best operating condition that you can get it in before making any passage. The sails, the engine, the centerboard, the steering, and the rigging should all work reliably. Otherwise, you are risking your life, and the vessel.