Trip Statistics! Part Two - Engine Usage

Hey everyone, Dave here again, back for part 2 of my posts covering statistics from our trip. Part 1 focused on how much distance we covered. This post will focus on how much we used our engine.

Total Engine Hours: 306.50

We started the trip with 509 engine hours and ended the trip with 815.5, putting a total of 306.5 hours on during the trip. The previous owners installed this engine brand new in 2009 and it had 390 hours on it when we bought it in September 2016. So, that's an average of around 55 hours per year for the 7 years before we owned this boat. In our first 19 months of ownership, we put another 119 hours on it, 65 of which was during our July 2017 trip to Nanaimo and Princess Louisa Inlet and back. That leaves 54 hours of various weekends throughout the rest of the year. Anyway, my point is we used our engine more in 3.5 months than the last 4 to 5 years combined! Having a reliable engine made this trip so much more enjoyable, especially because we depended on it so much. 

Average Engine Hours per Day Underway: 3.98

Taking the 306.5 engine hours we used and dividing it by the 77 days underway (as discussed in part one) results in an average motoring time of about 4 hours every day. That's a lot of motoring. I didn't write down the engine hours every day, so I don't have a "top ten" list as I did in part one, but generally, most days involved at least a couple hours of motoring. There was generally close to an hour at the start of each day as we pulled up the anchor, secured the anchor, motored out of the anchorage, got the sails up, etc. Similarly, there was generally close to another hour at the end of each day as we dropped sails, motored into an anchorage, found a good spot to drop anchor, set the anchor on the sea floor (by motoring in reverse until the chain is tight), etc. In between, we often motored for a bit when the wind died.

Some days we used the engine relatively little, like during our first overnight passage when we went 146 miles from Sitka to Bob's Bay and we used only 2.9 hours. This was mainly due to the attitude that we didn't have a specific destination we had to get to, we just wanted to see how far south we could make it in one overnight. On the other end of the spectrum, our second overnight (162 miles from Sgaang Gwaay to the northern tip of Vancouver Island) included 22.2 hours of motoring. This was because we got excited at the idea that we could do the passage in one overnight instead of two after the first evening when we had pretty good winds, so we motored all night in order to keep the pace high after the wind died. We've found how much we motor is really often about attitude and expectation of how fast and far we want to go that day.

Total Fuel Consumed: 98.49 US Gallons

We carried 5 jerry cans of diesel to supplement our fuel tank (a 6 gallon can, a 5.3 gallon can, and three 5 gallon cans). We theoretically have a 40 gallon fuel tank based on this boat's specifications and measuring the outside dimensions of it, but when our fuel gauge says our tank is half full (or is it half empty?) and we refuel we can usually fit around 10 gallons in there, so that would suggest we have a 20 gallon tank. I don't know if our gauge is inaccurate (on the cautious side), or our tank has thick walls or something, but my point is our tank is somewhere between 20-40 gallons. During our trip, we found this was plenty of fuel to carry, and most sailors we talked to actually got by just fine with less. A 20-25 gallon tank with 2-3 jerry cans was pretty typical from the conversations I remember.

We refueled 8 times throughout the trip: Kingston (on our first day as we headed north), Port Hardy, Shearwater, Ketchikan, Petersburg, Juneau, Prince Rupert, and Winter Harbour (two jerry cans only). Every time we pulled up to the fuel dock, we still had at least one full jerry can and could usually only fit another 10 gallons or so into our tank. We didn't bother refueling at Prince Rupert on our way north since we knew fuel would be cheaper in Alaska. In hindsight, we probably could have made it from Port Hardy to Ketchikan without refueling in Shearwater. We topped off our tank with 4-5 gallons there for peace of mind, even though we still had 5 full jerry cans and that was the most expensive diesel we bought throughout our entire trip.

I can say with confidence that Washington State fuel docks in Seattle's suburbs (such as Kingston, Des Moines, Bremerton, Brownsville, Port Orchard, and Oak Harbor) are the cheapest places throughout the whole inside passage to refuel. We found fuel was over $4 per US gallon throughout B.C.; Shearwater was the most expensive at around $4.50 USD per US gallon. Alaska was typically $3 to $4 per gallon. Juneau, at $2.96 per gallon, was the only place outside Washington State where we found diesel for under $3 per gallon.

It was also interesting to see how each government dyed their diesel different colors. Marine diesel in Washington State is dyed pink; in B.C. it's dyed green, and in Alaska it's dyed blue. It made our racor glass interesting mixes of colors as I'd check it throughout our trip. Even right now, looking at my racor it's got a green tint to it and I have to remind myself that it's ok that it's not pink. Anyway... I digress...

Average Fuel Efficiency: 0.32 US gallons per hour

98.49 gallons used divided by 306.5 engine hours equals 0.32 gallons per hour. This statistic I'm actually a bit surprised by. I've found that we typically burn about 0.5 gallons per hour when cruising at full speed. I think this 0.32 gallons per hour accounts for a lot of time spent idling slowly as we look for a good spot to drop the anchor, set the anchor, pull up the anchor, go slowly through narrow anchorage entrances, etc.

Average Fuel Consumed per Day Underway: 1.28 US Gallons

Dividing our 98.49 gallons by our 77 days underway equates to an average of 1.28 gallons used per day underway. Looking at statistics like this is when I really start to appreciate having a sailboat. Sure, we may go half the speed of a motorboat, but I don't think there's a single motorboat out there that could get to Alaska and back burning less than 100 gallons and cover 30+ miles per day on under 2 gallons per day.

Miles per US gallon: 28.43

Dividing our 2800 miles traveled by the 98.49 gallons used results in a miles per gallon figure of 28.43. So, it's about the equivalent of a small car or a hybrid SUV. Not bad considering we're driving something more like the equivalent of an RV; well ok actually more like an old van that's been converted into a plug-in hybrid and has solar panels strapped to the roof. Sailors like us are basically the hippie van-dwellers of the sea when you think about it.

Estimated Percentage of Time Motoring: 44% - 49%

This statistic requires a bit more judgment. I didn't keep a strict log of time spent underway, but I estimate our velocity-made-good was around 4.5 knots generally. Taking our 2800 miles traveled divided by 4.5 equals 622.22, so we can estimate that we were underway for around 620 hours. This equals about 8 hours per day (620 / 77 = 8.05) which sounds about right. So, dividing the 306.5 engine hours by the estimated 620 hours underway gives a figure of 0.49435. Rounding that to 2 significant digits tells us that we motored 49% of the time. If I adjust my velocity-made-good estimate down to 4 knots, that'd mean we were underway 700 hours (9 hours a day on average) and thus motored 44% of the time. Regardless, it's safe to conclude that we motored just under half of the time we were underway.

This is much different than the typical wisdom tossed around the local cruising community that "if you do the inside passage, you'll have to motor 80% to 90% of the time." Often, that's followed by "so you might as well do it in a motorboat." That wisdom is often due to people trying to do this trip later in the summer when winds are lighter. It's also spoken mostly by motorboaters that purposely go later in the summer when the winds are lighter so the seas are flatter. We followed much of the advice that Marilyn Johnson gives in her book Taken By the Wind (which we only bought due to the recommendation of Patrick and Natalie of S/V Violet Hour at a cruiser's meeting in October 2017). It was really useful to have that book before and during the trip in order to try and align our schedule as much as possible to maximize the amount of sailing we did. She basically says to leave early in the spring because the best weather for sailing in Alaska is in May and June, and by July it's time to start heading south. By heading north in the spring, we were able to ride more wind than we would have if we left in the summer.

We could have gotten that motoring percentage down even further if we had been more religious about maximizing sailing and minimizing motoring time, but we tried to balance that with not basing our destinations only on which way the wind is blowing (or if it's blowing at all). Like I said earlier, how much a boat motors is really often about attitude and expectation of how fast and far they want to go that day. But overall, we think the typical wisdom that everyone has to motor 80% to 90% of the time is a huge exaggeration. It's definitely possible to sail most of the time with some reasonable effort.