To enable widespread and rapid airborne bathymetric lidar to adequate depths in many ocean regions a low-cost, rugged, and high energy pulsed laser source must be developed in the ocean water transmittance spectrum of 450 - 490 nm. The ideal laser source will be high performance for lidar (high pulse energy, high rep rate, short pulse duration) with specific targeted emission spectrum to meet ocean water transmittance and filtering requirements. It will also feature low SWaP and a rugged form factor with high reliability for continual use on mobile platforms. No existing laser source can meet these demanding requirements. To address this challenge and meet NASA's lidar source needs, Bridger Photonics, Inc. (Bridger) proposes creating a high power Q-switched, off-line Nd:YAG source at 946 nm, which, when frequency doubled to 473 nm, will provide high transmittance through ocean waters. Bridger's design will leverage three key innovations: efficient, end-pumped, low-quantum-defect architecture; gain crystal design for optimal heat removal; and robust monolithic, alignment-free fabrication. The proposed design would allow for widespread deployment of mobile ocean-penetrating lidar transmitters. Bridger's overall goal for this Phase I effort is construct a breadboard prototype laser emitting 10 WAVG at 473 nm with a viable pathway to a rugged, turn-key system with >10% wall-plug efficiency to be built and delivered in a Phase II effort. Bridger has modeled and constructed similar lasers on Phase I SBIR efforts previously and will apply the innovations developed there towards this new system for NASA.