Sailing Umavideo

Making Space For More Batteries | Step 460

October 19, 2025 · 31 min · 133K views

Kika paints names inside cramped boat locker, smiling.

What this video covers

Dan and Kika replace Uma's cockpit drains and build a battery box in the cockpit locker as part of a larger electrical system overhaul. The old cockpit drains — 1.5-inch tubes routed through seacocks — are ground out and replaced with fiberglass stern-tube stock, chosen because it is stronger than hand-laminated tube without vacuum bagging or autoclaving.8:37 The new tubes are roughly double the diameter, giving approximately four times the flow area and eliminating the through-hull restriction; Dan estimates the cockpit will drain four to five times faster.3:44 The drain replacement was motivated by a rat that chewed through the original through-hull fitting while the boat was in Florida, nearly sinking Uma.1:52 With the drains glassed in and cured, Dan builds a plywood battery box — primed, painted, and assembled outside the locker before installation — to hold five of the planned ten lithium batteries elevated above the hull and above the waterline.13:16 The second bank of five goes under the companionway steps, separated by a watertight bulkhead, giving two independent Ocean Volts battery banks each with its own BMS.1:06 Kika spends four hours writing patron names inside the locker before sealing them under a final paint coat.19:49 Cockpit lid reinforcement and waterproofing, started in Guatemala in 2017, is deferred to the next episode.29:24

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