After the previous day’s lake crossing with high winds and close reaches, we were hoping for a comfortable spinnaker run up the Michigan coast. Southeast winds around 8-10 knots were forecasted for the morning, so I had the spinnaker ready to go in its bag on the foredeck before we weighed anchor from Pentwater Lake.
We cleared the breakwall around 11am to find the forecast spot on… southeast winds at 10. We sailed wing and wing northwest for about 20 minutes to give us some maneuvering room from shore, then flew the spinnaker on a starboard tack for a little extra speed.
We bought our spinnaker about 4 seasons ago for days like this one. I think flying a spinnaker, even an asymmetric like ours, allows us to sail more miles in light and moderate airs. Without it, I think we’d motor far more often, since it’s hard to keep the jib full on a broad reach. The extra sail area helps, too… more than double that of the jib while also using a very lightweight cloth. Additionally, we like the stable motion of the boat with the chute up, even in moderate waves.
It’s not magic, though. After an hour and 45 minutes and 9 miles, the wind died to under 4 knots, occasionally collapsing the spinnaker. We tried a hotter angle, but this still kept our boat speed under 3 with a much lower VMG northbound.
I strongly prefer sailing over motoring (it’s a sailboat after all!), but I also like to “get there.” The SailFlow forecast had called for very light wind (under 4 knots) starting around then, so the dying breeze was expected to stay light for several hours. After a few minutes of fussing with no improvement, we doused the chute, cleaned up our lines, and motorsailed with the main for a while.
We didn’t have anywhere we needed to be that night… I rarely make marina reservations… but I do think that flat water and calm winds are “good” motoring conditions, if there is such a thing. It was nice to click off a few miles towards our ultimate destinations of Frankfort and South Manitou.
About three hours later, I noticed the true wind speed increasing again to around 8 to 10 from the southeast. We could sail, but our progress would slow to around 5 knots rather than the 7 we were doing under power.
We had another decision to make… continue motorsailing another 3 hours for 21 miles and arrive in Frankfort around 7pm, or sail and try to make it to Arcadia Lake by around the same time. Neither Kristin nor I had been to Arcadia, and with settled weather in the forecast, it would be good conditions for us to explore somewhere new. It was a Sunday, also, and we figured a late arrival in Frankfort wasn’t worth the marina fees since many places would close before we could finish securing the boat. So, we chose “sailing.”
Having rounded Big Sable Point, our course to follow the shoreline was more northeasterly now, so flying the chute wasn’t very practical. With just the jib and main, our boat speed occasionally reached 6 knots. At an average of 5 knots, we figured we could get the remaining 15 miles to Arcadia around 7pm, before sunset.
The wind occasionally lightened, however, dropping our boat speed to under 4 knots at times. During the lulls, a glance at our GPS chartplotter revealed an ETA that was far later than we wanted. When the boat found some wind, the ETA would move back into the acceptable range. The forecast didn’t reveal any expected change in wind speed during the late afternoon, so we could only react to what was happening on the water. Which brings up another decision… continue sailing, or start the motor?
In my cruising the last several years, I’ve based my answer to the “When to start the motor?” question partly on forecasts, such as earlier in the day when the wind died as forecasted. When the forecast loses accuracy, or the wind gets light, I instead use some basic time, speed, and distance math.
First, I decide when the latest we’d like to arrive at our destination would be. On this day, sunset was at 7:30pm. Sunset seemed a good deadline, since the 45 minutes of remaining daylight would give us time to absorb any further delays and still allow us to anchor with some light. It would be nice to get there earlier, but I wasn’t willing to start the motor just to accomplish that. So, we wanted to be somewhere… probably Arcadia Lake… by 7:30pm.
Next, I estimate how fast we could motor (or motorsail) in the current conditions. Most of the time we can do a little over 7 knots on Priorities when motoring in calm conditions. This speed can drop off a bunch with a headwind or current.
I also consider whether we need to motor for reasons other than propulsion. With our solar panels and a decent battery bank, we rarely use engine power solely for charging our batteries, but on cloudy days this can be a necessity. Our engine also heats the hot water heater, so if our heater gets cold I’d consider wanting to run the motor a little more than normal. In either case, I’d rather use the motor when underway than ruin a peaceful anchorage with the sound of an idling motor. On this particular day, however, we had already motored for a few hours earlier, so our water heater was hot and batteries were charged.
Now I use some mental math. With an anticipated motoring speed of 7 knots we can cover 15 miles in just over 2 hours (15 nm / 7 knots = just under 2 hours, 10 minutes). At 4pm, this would make our arrival time about 6:10pm… way early. Even if we stopped moving altogether, we could wait until 5:20pm (7:30pm – 2:10) before we had to start the motor. This meant we didn’t need the motor just yet, so we continued sailing. Often times, more wind returns in a few minutes anyway.
Every so often, I recalculate. At 5pm, we had 10 miles to go. Starting the motor then would put us in Arcadia in less than an hour and a half at 6:25pm… still earlier than needed. Still, we kept sailing.
Unfortunately, a little before 6pm and just outside the Portage Lake breakwall, the winds suddenly went to zero, then shifted to north at about 5 knots. We could have given up and sailed into Portage Lake, but Arcadia Lake was something new to us and was only 6 miles away.
A beat can throw off some of my calculations. We had to tack to starboard tack due to the proximity of the shoreline, placing us on a northwest heading. This meant we weren’t getting any closer to Arcadia while on that tack. Our speed dropped a bunch, too, making it seem like we were making no progress. Motoring into the headwind results in a slower anticipated speed, too… especially since I didn’t know if the north wind would increase. While perhaps we could have sailed more, these factors convinced us that it was finally time to start the motor.
Fortunately, the winds stayed light, and we were safely anchored in Arcadia Lake less than an hour later. It’s a pretty spot, though there are houses most of the way around the lake. That night was super calm, and we got a great night’s sleep.
