Weather and tides

Tides for Matsushima bay Tides for Japan, listed north to south.

wind forecast (Sendai above, Shiroishi below)

Yahoo weather (Matsushima)

here is a site I use and you can change for other locations for sea surface temperatures and marine weather

Two about the beaufort wind scale and a useful summary

Here is a great list covering all the conversions metric to imperial etc which will cover you for wind speed conversions (m/s to knots = x1.943846)