The Round Rangitoto Race With MaxSea

Two of the wonderful things about being based in Auckland for the summer are the very active race scene here, and all the beautiful islands in close proximity to the city.

We took advantage of both last Saturday and participated in the Round Rangitoto Race, sponsored by Volvo Penta and the Posnsonby Cruising Club.
The interesting feature of this 26-mile race is that one can pick the direction in which the island is rounded based upon current and wind direction. It was a real crapshoot on Saturday, as a weak front was passing over Auckland in the middle of the race.

The volcanic peak of Rangitoto Island rising 250 meters out of the sea and appearing the same from any angle, dominates the Auckland area landscape.
Adjoining Motutapu with contrasting green hilly landscape also forms part of the course.

Clockwise or counter-clockwise? That is the question. To help us with the problem, I enlisted the MaxSea nav program. I first plotted the best possible course from the start, around “Rangi” and “Motutap.” I then downloaded a wind grib file from the MaxSea web site. Combining that with local VHF weather information, I knew we could expect winds for the start at about 10-15 from the west, increasing to 25 and backing to the southwest about mid race and then easing to 15 for the home stretch leg up the Waitemata Harbour.

High slack water was predicted to be just before the 1000 hrs start time and with a 3-meter tide the ebb would be strong. The current is typically stronger in the Motukorea Channel (South of Rangitoto) than in the Rangitoto Channel (West of Rangitoto). Based upon that, we felt it to our advantage to ride the ebb out in the morning and take Rangitoto channel later in the day when the negative current wouldn’t be so strong. Based on the wind forecast, doing the opposite would mean a long wind-against-current beat up the Motukorea Channel. No fun!

Given our relative lack of manoeuvrability against the rest of the fleet of 24-40 foot racer/cruisers, we had a good start and were soon running wing on wing with the #3 jib poled to windward. As you can see from the chart picture, we varied from our plotted course to find better wind and current and sail better angles, but it was helpful to have waypoints to give us a better idea of where to go.

The crack foredeck crew took us through four or five smooth gybes until we could get on a two-sail reach on the east end of Motutapu Island. As predicted the front came by, dropped some light rain and then moved on east toward South America. The weather fined up and the breeze freshened just as we came around the top of Motutapu. We tucked a reef in the main for the windward beat.

On the downwind part of the race, we quickly ate up most of the non-spinnaker fleet, excepting Urban Cowboy, a very quick race boat. Mind you we were still carrying our full compliment of cruising gear, ground tackle the washer/dryer, dive gear, TV, petonque balls, etc.

Having MaxSea tracking our course over the ground was particularly helpful here. We could see what the wind shifts were doing to us and plan the best time to tack so we could lay our marks. This was critical as we needed to clear Rangitoto light, (near waypoint 10) and didn’t want to put in any more tacks than necessary.

With a 15 year-old very tired headsail, we were a bit handicapped upwind, but we did manage to pull back Urban Cowboy, who was a bit over canvassed and rounding up in the 25-knot puffs., Elephunk, a 24’ hot rod managed to get us upwind.

The wind did in fact back to the southwest, but we made the lug up Rangitoto channel on one tack. We put a little in the bank, tacking back to port just near Bean Rock. Here we were able to crack sheets a bit and really get moving. In the last two miles, we managed to shrink significant leads by both Elephunk and Urban Cowboy to a three-boat overlap at the finish line. The course was a half-mile too short! At the end we were third on line and in the cheap seats on handicap, but enjoyed a great day of Hauraki Gulf sailing.

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