DREDGING 101

(Published in the November 2018 issue of Ski-Boat magazine)

By Ryan Williamson

THE proof of the pudding is in the eating thereof, or so the cliché goes. For me, during the prototype design and manufacture of a dredge to be marketed by Pulsator, the ultimate goal was to take a few completed dredges to Cape Verde during my three-month skippering stint there during the blue marlin season, and to test them under the most brutal blue marlin fishing conditions in the world.
Both Stuart Simpson and I pulled the Pulsator dredge very successfully during this season, proving that they raise fish and also expanding our practical knowledge of how to swim the dredge while ensuring we as skippers and our crew made the most of the marlin we raised.
I hope to pass on this knowledge to the marlin anglers in South Africa in the sincere hope they will raise more billfish in the season to come.
At the outset I want to emphasise that, yes, all our experience has revolved around fishing from sportfishers, but with the modification I suggest I am convinced that dredges will also be an asset to those fishing for sailfish and marlin off ski-boats.
Let me state here and now that the primary role of a dredge is to imitate a shoal of baitfish and create activity through contrasts just under the water’s surface. This is achieved not only by the colours used in the “bulb” squids, but also by the polycarbonate fish replicas seen as a flash/contrast foil, which are more streamlined, thereby making the dredge easier to pull.
Dredges pulled from ski-boats proved very successful during the last marlin season at Sodwana, so yes, this strategy is viable for even the 18ft class ski-boats — with a few modifications.
Firstly, on a ski-boat I recommend you use a slightly smaller 34-inch dredge with a lighter 3kg weight. The deployment of the dredge also needs to be carefully considered, especially if lighter, more flexible outriggers are installed.
My advice is that unless your craft has substantial outriggers stayed with support stays from forward, a stern cleat should be used with 6- to 10mm “yachting” cord (approximately 20m long) securely attached. This length will be adequate because the dredge is usually deployed 8- to 15 metres behind the boat. The terminal attached to the dredge remains the same (see diagram A) but it’s of utmost importance that you use the highest quality swivel cleats and snap shackle possible.
Set out below is a list of some of the most popular electric reels, spread across a fairly wide price range.
• LP 1200 / 2400 Lindgren Pitman
• Kristal Fishing
• Miya Epock
• Magic Marlin
Some of the other hardware we use and which proved effective in our setup in Cape Verde is one 2-inch ball bearing pulley, attached to the rigger, plus a 1-inch ball bearing pulley, attached to the dredge. Harken or Ronstan are best. You also need heavy duty ball bearing swivels and D shackles.
Larger boats with aluminium spreader bar outriggers, are able to pull the dredge from the rigger. A pulley system using a short stiff rod loaded with an electric/manual reel is mounted on the gunnel or a tower rod holder close to the base, aft of the rigger. Hard monos from 400-600# are best (60m or less).
To start with check that your supports/connections are strong enough to pull the dredge. In SA it’s a good idea to upgrade your rigger back bar to solid stainless steel, or a thicker wall support (24 foot-plus) due to our rough conditions. When in doubt run a cord (4-8mm) from the dredge attachment point on the rigger to a point forward on the boat like a cleat or railing etc. This will reduce the strain on the rigger from the dredge.
Choose the rigger on the side that best suits the vessel — the side where it’s easiest to store the dredge, where you have the clearest access to the dredge reel and where there’s the best visibility for the captain. Neither side is automatically better than the other.
The right distance of the dredge behind the boat depends on drag from your dredge because this changes the depth at which it swims. You don’t want your dredge to sit too deep in the water as spotting fish on the dredge then becomes difficult. Ideally your dredge should run 1m to 3m below the surface. Do not allow the dredge to break the water’s surface.
If your dredge is sitting on your first wake then, depending on the boat size, it will be between 8- and 12m behind the boat.
Set the drag on the reel so it can take the strain of the drag whilst trolling/retrieving, but it must not be locked up fully as a fish can get wrapped up from time to time which will test your rigger to the max!
Please remember when you pull a dredge the physical drag depends on the size of your dredge and weight — a combined weight of between 20- and 40kg — so to retrieve this while the craft is trolling at about 8 knots is not child’s play. Whether you are retrieving using a cleated cord, a heavy downrigger reel or, as suggested, an electric reel, be extremely careful and have a dry run of both deployment and retrieval so all the crew know how the task should be done and where the dredge should be stowed.
Stowage of the dredge has to be thought through to ensure the arms are not damaged and the squid lines and polyfoil are not tangled. Just imagine a 20kg bull dorado on the deck tying itself up in your dredge if it is left lying on an open deck!
I further recommend that when using a dredge for the first time one should commence the trial exercises in light to moderate sea conditions. Above all, do not use a dredge in heavy seas. Not only do you risk losing your dredge, but there’s also a much greater risk that accidents will happen during the exacting deployment and retrieval of a dredge in those conditions.
Please also ensure the maintenance of all aspects of your dredge is 100%. Dredges are not cheap and they endure a significant degree of stress when being towed around the ocean. Continually check lines, swivels, cleats and shackles for wear. When stowing it, hang the dredge up and or collapse the arms correctly to avoid bending them.
Even though the Puslator dredge is made of 316 stainless steel and the arms of spring steel, they need to be looked after if you want them to last.
Now for some details on how to fish a dredge… First and foremost you need to decide on the style of marlin fishing you intend to undertake. When using a dredge you basically have two options — one is bait and switch baiting or pitch baiting, and the other is the traditional style of pulling a spread of rigged lures.
It is absolutely essential that the dredge is immediately taken out of the water when a crew member or skipper has spotted a fish. The reason for this is that in Cape Verde we saw that if the dredge is still in the normal trolling position it can give the fish too much choice between chasing the dredge or your lure. I must emphasise that this is really important. Anglers need to ensure that one person is in charge of this responsibility, thus avoiding confusion on the deck
As a start, especially at venues like Sodwana Bay and Richards Bay, I would run three rigged lures from the outriggers in the traditional fashion with the dredge, and have one standby pitch rod with a bait ready. In Cape Verde our technique was that if we had a fish that came up lazy behind the lure or if a stripey came up behind the lure (which can sometimes be difficult to hookup), we would start teasing the fish in by pulling the lure in, deploying a pitch bait rod into position and getting the fish to switch from the lure onto a bait rigged with a circle hook.
Don’t use the five lure spread to start with as this will lead to too much confusion when you’re just getting used to using dredges. With having the dredge in the water, which is substantially bigger, there is no need to think that you have less chance of attracting fish with only three lures in the water. Once you get more experienced you can add a fourth lure to your spread, but keep a pitch rod ready at all times.
It is important to run your lure from the rigger position, fairly close to the proximity of where the dredge is — about 2m on the outside of the dredge and 2m behind the dredge. The same would apply if you were to run a lure teaser.
In my personal experience over the last two seasons in Cape Verde, with the lures positioned closer to the dredge, 60% of my bites have been on the lure that is on the same side of the craft as the dredge, fairly close to the dredge and almost parallel to the tail end of the dredge. The two other lures on the opposite side of the boat to the dredge can be placed conventionally but not too far aft. (See diagram B.)
If you intend using only the pitchbait method you would run your hookless lures as teasers in the same position on the shorts as per Diagram A, and then have a stinger (shotgun) rigged lure. The reason for this is that if the fish loses interest in the teasing and falls back, having a stinger gives you a second shot at jamming the fish. (See diagram C.)
If the captain or crew spot a fish on the dredge the captain must turn the vessel towards the dredge side. This draws the dredge into the clearer water, thus allowing the skipper to have a better view of the dredge and of the fish’s actions.
Both the early morning and late afternoon sunlight can make it very difficult for the captain and crew to see fish on the dredge, so you’ll often need to look out for other signs too, like a dorsal fin, tailfin or boil behind the dredge. When the sun is higher it’s much easier to spot fish on the dredge. Spotting a black shadow, electric tail or pectoral fins are all indicators that the dredge should be removed from the water.
In both instances one needs to divert the marlin’s attention from the dredge to the lures or pitched bait. As soon as I see any indication that a fish has been raised I instruct the crew to switch on the electric reel and get the dredge out of the water as quickly as possible. The same would apply if one is hand-pulling a dredge run from a cord from the aft cleat.
Remember not to use a dredge that you are not able to retrieve. For example rather look at a 3kg weight and a 34-inch dredge if you are going to be using cord line and pulling it in by hand. This aspect is very important as the dredge creates a great deal of drag and retrieving it to a hanging position on a big sportfisher using an electric reel is a lot easier than retrieving it by hand when dredging from a ski-boat.
See Diagrams B and C for dredge-set up using an electronic reel.
Deployment from the aft cleat on ski-boats is practical and does work, but make sure that when the dredge is being retrieved the motor nearest to the dredge is put into neutral to reduce the chance of it getting tangled in the outboard’s propellers.

WHEN YOU SEE A MARLIN…
I have been asked what I do if I see a marlin mark on my sounder. My sounder is set to scan from the surface to 150 metres so that it will hopefully pick up the marlin which usually swim at between 30- and 100 metres, and also bait showing below this depth. Bait showings indicate an area to be worked even if marlin are not marked. If the billfish are in the first 0- to 15m you will seldom mark them on your sonar.
If you pick up a marlin mark it’s essential that you turn 15 degrees on the helm towards the dredge side, allowing the dredge to come into clearer water, making it easier for the captain or crew to see the fish behind the dredge. Once you have turned 15 degrees, hold course for at least 300- to 400m. Every fish behaves differently, and if fish are marked at a shallower depth they will be up on your spread a lot faster than fish which are deeper in the water column.
If you have marked a fish and you do not allow a long enough period for the fish to come up into the spread, you might lose it. Often you will raise the fish on a sharp turn, thus changing the performance of the lures that you were turning on as they slow down on the turn. I have seen this happen numerous times, where the fish then fades off due to the lures on the inside stalling.
If you have not raised a fish within your 300- to 400m run you can then start turning back to the area where you marked the fish and see if you can get a second run at your marked fish. see Diagram D for an example of the troll pattern I would use.
Dredging adds a new and exciting dimension to the sport of targeting billfish and, for many of us, has produced incredible results. I think that running a dredge most certainly helps to raise fish up from deeper water, and the side profile of the dredge can be seen much more easily by fish than a surface lure smoking. The other great thing about a dredge is that you’ll find that 80% of your bites are on your shorts, and if you have not hooked up on the first attempt, most fish will fall back and have a go at your longs. This gives you a second shot, whereas if you miss a fish on your long it very seldom comes forward to eat your short.