Nov 22 (Reuters) - Top U.S. automaker General Motors Co (GM.N) has bought a 25% stake in Pure Watercraft, valuing the electric boat startup at $600 million, the companies said on Monday. GM is offering $150 million in a combination of cash and payment-in-kind, which includes access to the automaker"s components and assistance with manufacturing, in exchange for the stake, Pure Watercraft said. Founded in 2011, Seattle-based Pure Watercraft makes electric motors for boats powered by lithium-ion batteries and uses a plug-and-play design mechanism that allows for any boat hull to use its motors. "Building upon GM"s existing efforts to deploy our technology across rail, truck and aerospace industries, the combined expertise of these two enterprises should result in future zero-emissions marine product offerings," Dan Nicholson, vice president of GM"s Global Electrification unit, said in a statement. The carmaker in October outlined plans to double its revenue by 2030 and become the leader in U.S. electric vehicle sales. read more GM said it would disclose any products developed from the partnership with Pure Watercraft at a later date.