That is the main ambilocal harness from Yamaha to the dash. This harness IS NOT installed at Bennington factory but rather is a dealer mistake. If the rubber coating has any damage at all you need to request your dealer who rigged the boat to order and install a replacement harness. A lot of water will be in contact with this harness over the years and any violation of the protective coating is certain trouble in the future.
Yamaha makes these harness very long as they do not know what size boat it will be rigged to. The dealer who rigs the boat should coil the extra and tie it SECURELY out of the way. This is normally secured to below deck inside frame above a pontoon.