my Avant is pretty low (it's on coilovers) and I use the ferries up here in WA fairly often without issue, even during extreme low and high tides. My biggest concern is always dragging the undercarriage as I pass the breakover point but that hasn't happened yet on a ferry boat. It does however happen every time I leave the downtown REI garage for some reason.

I know that's not a ton of help, but I thought I'd toss that out there. I usually take the Fauntleroy-Southworth run but have also taken the Clinton-Whidbey, Edmonds-Kingston, Seattle-Bainbridge, and Seattle-Bremerton without an issue yet in 1.5 years of ownership. When in doubt I just time my boarding in traffic so I can go at a bit of an angle up and down the ramp. Hope that helps a little.

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