Originally Posted by Chris
Keeping a rib on a constant compass bearing is not easy as we saw when we used the iphone and a handheld Garmin Etrex to keep an eye on the course. We were keeping our speed at a constant 15 knots but if we had relied upon just a compass and distance over time calcs then we would have been stuffed.
Do you not have a proper compass on your console? Using GPS to determine heading is rubbish because it shows you is the average heading that you were on a moment ago - not where you are heading now. Steering a compass course is a skill (whether on a rib or any other boat) - it was covered in my PB2. There might be a "magnetic" compass in your phone too - but it will be heavily damped so I doubt its accurate / precise enough to navigate properly by.
How bad was the Vis? 15 knots still sounds quite fast if you can't see anything. How quick can you stop / avoid an obstacle?