Digital Circuit Designer for boat bilge alarm System

I'm seeking an experienced digital circuit designer to create an alarm system for a bilge pumping system on a boat. It’s a one off project.This project is for my existing business.
When the 24 volt 15 amp bilge pump activates, from a float switch, a light and buzzer must sound.
When the pump has deactivated because the float switch has deactivated, bilge empty, the light and buzzer must stay on until a reset button is manually pressed. If the float switch reactivates the light and buzzer must stay on until reset is pressed.
The alarm is to warn the boats skipper the boat has a problem which needs solving.


Key Requirements:
- Design a digital circuit specifically for a marine alarm system.
- Ensure stability and reliability in various operating conditions. Wet , violent movement, noisy.
The design must be cheap and easy to build. The design of the circuit must be cheap too.

Ideal Skills and Experience:
- Expertise in digital circuit design
- Background in circuit design
- Strong problem-solving skills
- Ability to provide detailed circuit diagram

Looking forward to your bids!