If fuel costs are a major factor in limiting the amount of boating and fishing you can afford to do, there are ways that you can constrain expenses while still getting out on the water, says Sam Mossman.
1) As with cars, the way in which you drive your boat can make quite a difference to fuel use. Running outboards at wide open throttle (WOT) is an extremely expensive practice. For the gain of just a little extra speed, you will use a disproportionate amount of extra fuel. Try and keep outboard revs around two-thirds of the rated maximum, or below, when travelling.
2) The pitch of your propeller can have an effect as well. Pitch is measured in inches; that is, the theoretical number of inches that each turn of the propeller will drive the boat forward. A fine pitched prop, for example, of 16” or less, will have good acceleration and low speed torque – great when water skiing. A coarser pitched prop – 17” or above – may not make your boat leap out of the water like a startled rabbit but will drive it further with each turn of the screw once it is on plane. Obviously, you should not over-do the coarseness of the pitch, or you will be straining the engine (shown by the maximum revs at WOT dropping out of the preferred range) and will run into other problems, such as lack of response in a bar crossing situation. But as a rule of thumb, a coarser pitched prop will be more economic for travelling longer distances.
3) Pushing a planing hull design at high displacement speeds for any great distance can really hog the juice. These hulls are made to travel over the top of the water and are much less efficient when ploughing through it at lower speeds. This has caught out a lot of people over the years: they have plenty of gas for a normal day at sea, but when the weather turns to custard and they are forced to travel home at high displacement speed, or they catch a big fish and must tow it in, they can find themselves short of fuel.
4) Correct boat trim makes a difference too. Obviously, the ideal trim for each boat is different, and changing sea conditions can further change this. Trim the bow down too hard, and you are ‘ploughing’, i.e. inefficiently pushing water. But trim the bow up too high and the engine is straining to hold it there and the hull may ‘pound’. Try this: set the throttle at a reasonable planing speed, then run the engine through its range of trim. The revs will increase and decrease for the same throttle setting depending on how freely the boat is travelling. Try to find the maximum revs for the given throttle setting, tempered by comfort, speed, prop aspiration (sucking down air) and safety aspects, of course.
There are several devices that can aid in adjusting the trim of your boat. These include trim tabs, and extensions that bolt on to the cavitation plate of your outboard. These devices can, in some instances, make a great difference to the performance of your boat and contribute to fuel savings.
5) Load makes a difference to fuel use. Go through your boat and take out all the unnecessary items that have accumulated in it, or even just stuff you will not need for that day. Do not sacrifice any of the safety gear, though.
Go through your boat and take out all the unnecessary items that have accumulated in it.
6) Some outboards are more economical than others. Modern four-strokes, and two-strokes with computerised fuel injection systems, may cut a great deal off your fuel and oil bill, compared with older models. However, the capital outlay is higher to buy these engines over older designs. If buying a new outboard, you will have to do the maths for your own situation to see which is the most economic option.
7) What about fuel computers? These electronic devices will give fuel usage information and an accurate reading of the fuel left in the tank. Particularly with outboards, a fuel computer can be handy to work out the most economic range of the engine in various sea conditions, trim and loading.
8) Launches with diesel engines can be a lot more economic to run than outboards, although in the last couple of decades the price of diesel fuel seems to have increased at a faster rate than petrol. Once diesel was half the price of petrol; now it is about two-thirds the cost.
As with outboards, you can nearly double your fuel use for just a handful of extra knots as you get close to full revs with some diesels. With displacement or semi-displacement hulls, travelling at displacement speeds can be a lot more comfortable and economic, as long as you are not in a great hurry. At these sorts of speeds (7-9 knots) you may as well have some lures out – you never know what you are driving past.
Diesel engines can be a lot more economic to run than large outboards.
9) Liveaboard launches and large trailer boats have the advantage of allowing stay-away trips. In some places it is possible to overnight close to your fishing grounds, which means less running backwards and forwards each day, reducing fuel use.
10) Most launches are kept on moorings or in marinas and can accumulate significant marine growth on the hull. Don’t neglect cleaning the bottom; removing this growth can make a lot of difference to a launch’s fuel efficiency and speed.
11) Assuming everyone chips in for fuel on a trip, it makes sense to go with a full crew to make it cheaper for everyone. Consolidate crews, within reason and safe loading. For example, it makes little sense to have two guys from a campground go in one boat, and one on his own in another boat, if three of them can safely fish from a single craft.
12) Better navigation can make a big difference to running distance and costs. This is where using a GPS to plot a course and sticking to it can be very worthwhile. Before you leave, decide where you are going, and go by the most direct, safe route possible. The shortest distance between two points is a straight line.
13) Choose your fishing spots with care and spend more time targeting spots that are closer to home. There is no point in spending a fortune on fuel travelling ‘way over the horizon’ if there are plenty of fish to be had nearby. You may well get two or three trips to handy spots for the price of one long range expedition. Besides using less fuel, less time spent travelling means more time with a line in the water. The more you fish at a spot, the more local knowledge you build, and the more successful you will be.
14) Handy spots may often be fished from a smaller, cheaper-to-run craft than the larger boats with bigger, thirstier outboards required to run longer distances.
Smaller boats fished locally can greatly reduce fuel costs.
Trolling lures all day at eight knots can be an expensive proposition. Although you never know where you will find fish, try to fish intelligently, and consider alternative methods to lure trolling.
15) Go where the fish are. Try to get inside information on where the fish are holding from recently successful crews. Use hydrographic and bathymetric charts to target structures like the shelf edge, canyons and sea mounts. Sea Surface Temperature charts (SST) are available for a small charge (and sometimes for free) over the internet. These can lead you straight to a hot spot, and save you roaming vaguely all over the ocean hoping to trip over some activity.
16) When you do find an ‘active’ area with good water temperatures, birds, baitfish, current lines and other indicators, don’t just give it the ‘once over lightly’ and continue on your way – stay there and fish it intensively. Some techniques for fishing this way can use a lot less fuel and produce more action than lure fishing.
When you do find an ‘active’ area with good indicators, stay and fish it intensively.
17) Learn to use baits. For a start, baits are a lot cheaper than $100 lures – all you have to do is catch them. Trolling live or dead baits usually takes place at one to four knots or even on the drift. This uses a lot less fuel than lure trolling at eight or ten knots. While baits are not necessarily an efficient technique when you are prospecting for fish concentrations – you might not cover enough water at low speeds – when you have located some activity, baits will often work better in a concentrated area.
18) A technique from the early days of game fishing was to shut down the boat and deep drift with dead or live baits over deep structure. This used to produce some huge fish, including black marlin and very large sharks early in NZ’s game fishing history. It is still effective today, being used for daytime deep dropping for swordfish. Some Whakatane-based boats fished for marlin this way at the Three Kings very successfully, with some useful by-catches of big kings and hapuku.
19) With a few tuna starting to make a modest comeback in our waters, it is time to remember our history. While tuna fishing in the Bay of Plenty in its heyday, we used to catch a lot more tuna of all species by either livebaiting or cubing on the drift than we ever did by trolling. Once we reached a fishy area, there was only the occasional re-position to burn up a bit of gas.
20) Finally, as you do when filling your car, shop around for best fuel prices.
With a little more thought and planning, you can stretch your fuel budget further. And if you can do two carefully planned trips for the price of one casual one, you can obviously double the amount of fishing trips that you can afford. You may even find that you catch more fish!
July 2021 - Sam Mossman
New Zealand Fishing News Magazine.
Copyright: NZ Fishing Media Ltd.
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