LONG-TERM TEST: SEA JAY 4.65 DISCOVERY SPORTS & YAMAHA F70
THIS little tinny from Bundaberg-based Sea Jay Boats has opened up new and exciting sportfishing opportunities for me. While I still love chasing reds, tuna, kingies and billfish in the Fisho Bar Crusher 670, the Discovery Sports has reacquainted me with the simple joys of estuary sportfishing. Compared to offshore missions chasing big but elusive gamefish, a day out in the Sea Jay targeting popular estuary species like bream, flatties, bass, EPs and jew is easy, fun and very affordable. The 100 litres of fuel I’d use on a big day trolling the shelf, for example, represents probably a month’s worth of juice used on bream spinning trips. Sure, you can’t really compare a 1kg bream to 90 kilos of rampaging striped marlin or a 50-kilo southern bluefin tuna – but I don’t tend to get hung up about stuff like that. As long as I’m out on the water catching something I’m happy.
As you read this I will have clocked up 100 hours in the Sea Jay. Time spent on a boat gives you an excellent insight into how the vessel performs across a range of conditions, as well as allowing you the ability to comment with some authority on its individual strengths and weaknesses.
This write-up is aimed at anglers in the market for an inshore/estuary sportfishing boat. I want to be able to give you an unbiased and honest appraisal of this particular rig, based on my time spent fishing out of it. Hopefully the info over the next few pages will help you in making an informed purchase decision, if and when it comes time for you to fork out for a new boat. At the very least, it should give you a reasonable idea of the features and attributes of the 4.65 Discovery Sports that you can use when comparing it against other brands and models.
The 4.65 Discovery Sports is best described as an estuary/impoundment sportfishing boat. It’s designed for use mainly in sheltered waters. As such, stability and deck space are more important design characteristics than “performance”. Don’t get me wrong, this little boat rides as well and goes as quick as any comparable vessel but it’s not made to handle swell or serious chop. Standard estuary chop is no problem but once the wind really gets puffing, high-speed work will result in a few bangs and a fair bit of spray. Slow down to reasonable speeds and things become more comfortable and much drier.
I’ve found a cruise of about 16 knots with the 70hp Yammie four-stroke working at 4000 RPM and using nine litres of fuel an hour allows for a relaxed and economical ride in all but the choppiest of conditions.
To my mind, performance of the boat while you’re actually fishing is more important than that displayed while travelling to the chosen fishing location. While the Discovery Sports doesn’t go anywhere near as fast as any of the current breed of high performance US bream/bass boats (that said, it doesn’t use anything near as much fuel as these high-powered speed machines!), this Aussie-built tinny gets full marks when it comes to being an effective, comfortable and safe fishing platform. I’ve found it to be extremely stable, even in windy/choppy conditions, and the deck configuration allows plenty of room for active lure fishing. Fishing two up is probably best in regards to overall casting efficiency but I’ve fished three on many occasions with no probs at all.
Storage on this boat is adequate but compared to the much more expensive and specialised American style bass boats it’s a fairly limited. The first of two hatches in the forward casting deck, which extends 1600mm back from the bow, has ample room for an anchor, chain and 50m of rode. The second hatch hides a shelf for the battery plus room for a bucket, cleaning materials, a couple of yoke-style PFDs and mooring ropes. Shelves in the side console offer quite a bit of room for tackle, a toolbox and associated oddments. The 400mm rear deck at the transom lifts in two sections to reveal extra storage for more PFDs, a hose, lure boxes, a paddle and a 5l spare fuel tank.
A rod locker and a side pocket would be useful additions to this boat but both would encroach on valuable fishing space so I can understand why these extra storage options aren’t fitted. I’ve fitted vertical rod holders on the front of the console to help alleviate the rod storage issue and have added knife, plier and Boga Grip holders to the port side of the console, along with a drink holder. On the positive side, restricted storage space means you don’t clutter your boat up – you just take what you need, which isn’t a bad way to operate …
This boat features a 3mm pressed alloy hull supported internally by a system of welded stringers and braces all in-filled with flotation foam. I had pictures taken during the build process and can report that the sub floor set-up is right up there in regards to strength and durability. As is standard with this style of boat, the floor is constructed of sections of carpeted marine ply screwed into various struts. This flooring system is convenient as it allows you to easily remove sections of floor for maintenance inspections or if wiring up new electrics. To date the floor remains as solid as when the boat was first delivered, apart from a spongy section on the starboard side just athwart of the front casting deck. I plan to assess what’s going on here when I get the chance – it’s no biggie as it’s not an area that sees much traffic.
Upper decks are 2mm pressed alloy. The nicely rolled gunwales are of a generous width (160mm) around the entire boat. My strapping teenage sons Jack and Harry stand on these and fish – they have much better balance than me! Interestingly, even with boys standing side-by-side on the gunwale, the boat barely leans – this is testament to its excellent lateral stability.
Design & fit-out
As mentioned in the original review I did on this boat in the February 2011 edition, I didn’t opt for any upgrades other than SeaStar hydraulic steering. The boat came standard with pretty much all the features I wanted, including a plumbed bait tank, bilge pump and nav lights.
After using it extensively since then, I can report that the only extra I wish I’d had factory fitted was a much larger live well. The standard livie tank fitted on the port side of the transom is ideal for storing live prawns or poddy mullet for estuary baitfishing trips but is not big enough to keep slimies or yakkas alive for inshore kingie sessions. In recent years I’ve started fishing a few social bream tournaments and the tank as fitted doesn’t conform to specifications required by these C&R comps. This has resulted in some fairly dodgy DIY livewells being constructed using various pipes, plastic boxes and eskies …
Apart from the usual minor scratches and marks in the blue and white paintwork courtesy of my haphazard approach to docking and mooring, there are no signs of any cracks or splits in any of the welds. No water runs out of the hull after removing the bungs, which indicates that the hull is as watertight now after significant on-water and towing time as it was when first purchased.
Sea Jay has a reputation for producing quality boats and the build standards evidenced by the workmanship on my Discovery Sports reveal that this reputation is warranted. This has proven to be a good, solid and very well made boat. I honestly can’t fault any aspect of its build, construction or hull design.
Modern estuary sportfishing boats like the Discovery Sports are more often than not augmented by the addition of a couple of accessories, namely a bow-mount electric motor and at least one decent sounder. The Discovery Sports comes with a plate welded to the bow to allow for an electric. As has been written many times before, these motors are pretty much mandatory for any sort of serious lure fishing. I originally fitted a Minn Kota 55lb Terrova ST Riptide electric motor powered via a M Power Ultimate UL-100 battery. About six months ago I retro-fitted the Terrova with Minn Kota’s revolutionary i-Pilot system. The main benefit of this – or the feature I’ve used most – is the “anchor” system which enables you to press a button and stay in one position no matter the wind or tide. This is amazingly useful when lure casting and it has certainly been the difference between success and failure during some of my more recent sessions chasing bass and jewies. Depending on conditions, the anchor system takes maybe 30 seconds to a minute to work itself out. Once locked in, it will keep the bow of the boat in position, allowing you to more effectively work your lures. This is an extremely useful tool.
The other interesting aspect of the i-Pilot is its ability to record trolling routes. I don’t tend to do much trolling in my home waters but I reckon I’ll be putting this feature through its paces during a few trout sessions I have planned down at the Snowy Mountains lakes in coming months. Stay tuned on this …
I’ve previously written about the Humminbird 898 SI I had fitted to this boat. As well as traditional sonar, this unit boasts a “Side Imaging” system that works via a 180-degree sonar beam. This allows you to “see” bottom structure up to 240 feet either side of the boat, as well as directly underneath.
From a fishing perspective, Side Imaging is a real game changer. You can use it to find and then fish structure that you otherwise wouldn’t know was there. Also, you can assess underwater topography, find bait and even spot and target individual fish. I’ve spent a fair bit of time fiddling with my 898 and I reckon it’s an amazing bit of kit. I don’t profess to be any sort of electronics expert but the fast that the unit allows me to “see” where I’m casting is pretty amazing. Most of the fish I target – bream, bass, EPs – are fairly small and they don’t show up that well on the screen. For example, a small school of average sized bream shows up as white dots that look like cooked rice. Talking with other anglers who’ve used Humminbird side imaging units when targeting bigger fish such as cod or barra reveals that these larger specimens most definitely show up on the screen and can easily be identified. If the pros ever stop netting the Shoalhaven of its breeding size jewies, maybe one day I’ll get to use the 898 to locate schools of big mulloway…
Like most modern sounders, the Humminbird is pretty easy to operate after you’ve spent a bit of time fiddling around with it. One feature I really like is the ability to easily access screens to view Side Imaging, Down Imaging and conventional sonar via “pre-set” keys.
The transducer on my boat loses signal at about 10-12 knots, which is pretty annoying. I’ve tried adjusting the transducer so that it sits further down in the water column but so far have had no luck attaining better readings. At slow speeds it works fine but once you get on the plane it all goes fuzzy. I think I’ll need to get a marine electronics professional to take a look at the transom of the boat and assess where the transducer needs to be positioned. Who knows how many fish I’ve missed just because the sounder isn’t showing a clear reading!
While reading the notes on this boat that I’ve compiled over the past year or so, I came across some interesting statistics. The Sea Jay is rated to engines up to 80hp and 180 kilos. The engine on the boat is a 70hp Yamaha four-stroke, which weighs 120kg. So it’s just 10hp off the max power but a massive 60 kilos under the weight limit. On a relatively small boat like the Sea Jay, 60kgs is significant. And it goes without saying that as a result of the Yammie’s power to weight ratio, performance is pretty impressive.
Launched in 2010, the F70 shares the same displacement and stroke of Yamaha’s long-established F60 – it’s an in-line 996cc four cylinder four stroke with four valves per cylinder activated by a single overhead camshaft. According to Yamaha, the 16-valve design allows the engine to “draw fuel and air in and push exhaust out” very efficiently. The new engine also utilises a lower reduction gearbox than the standard F60; this helps with pushing heavier loads and faster out-of-the-hole performance.
This efficiency and increased performance is evident on the water. Initial tests revealed that 70, fitted with a stock standard alloy Yamaha prop, reached a max speed of just under 30 knots.
Here are the fuel and speed readings with the standard 13.5 x 15” alloy prop.
RPM LPH KNOTS
700 0.7 0
2000 3.8 5.3
3000 7.6 8
4000 10 18
5000 15.3 24
6000 22.9 30
I recently upgraded to one of Yamaha’s 13.5 x 14” stainless steel props and recorded a new set of figures.
RPM LPH KNOTS
700 0.7 0
2000 3.4 5.4
3000 6.8 8.3
4000 9 16
5000 14.4 24
6000 23 29
6400 24.3 31
This data shows that I’m getting slightly better economy at a fast cruise of 24 knots at 5000rpm. The engine is also revving out more freely (6400 @ WOT as opposed to 6000 with the alloy prop) but I’m only gaining one knot at top speed and using an extra 1.4 litres of fuel.
I guess I could try a few different props in order to boost top speed and maybe shave a bit more off the fuel usage but the amounts of petrol we’re talking here are pretty minimal … The big plus of the SS prop is that it has negated an annoying low speed rattle that used to drive me nuts!
I know it sounds a bit clichéd but the Yammie has started first pop every turn of the key, is super quiet and I can’t recall ever seeing or smelling any exhaust fumes. It’s a beaut engine and, again, I honestly can’t fault it.
As detailed in the original write-ups, I purchased a custom-built alloy trailer from Pro Alloy, the boat and trailer building arm of Boab Boat Hire. The main reason for going alloy was to reduce tow weight so I didn’t have to worry about getting mechanical brakes fitted to the trailer. The single axle Pro Alloy trailer weighs just 170kg, meaning total tow weight is about 660kgs, well under the 750kg limit for unbraked trailers. Another plus was that compared to a standard gal trailer, alloy has significant benefits when it comes to corrosion issues. I’ve just recently had the trailer serviced by the Amara boys. This included replacing the bearings, welding up a couple of minor non-structural cracks and fitting a couple of extra struts on the frame for additional strength. Custom alloy trailers like this cost a bit more than a standard gal model but my way of thinking is that a decent trailer is an integral part of the package. It’s false economy to get the best boat and engine you can and then sit the rig on a cheapo trailer that will either corrode away or just rattle its self to bits. I reckon the Pro Alloy trailer is a beauty and I’ll certainly be getting another one built for any other boat I may purchase. The trailer under the Sea Jay has an array of centre rollers for the keel and side skids for support, meaning the boat is easy to load on and off and travels well when underway. A strap at the transom, plus a turnbuckle arrangement at the bow, allows the boat to be securely bedded down while towing. A welded alloy walkway assists greatly if winching the boat on – this is a great feature that should be standard on all trailers, in my opinion. The lights are all LED and the trailer features quality Titan and Durahub components. It came complete with a spare wheel and is easy to tow and reverse.
As already stated, the boat came standard with most features common to a modern sportfishing vessel. Aside from the electric and main sounder, I’ve installed a Garmin echo 500c colour sounder at the bow. I’ve also fitted a fire extinguisher to the underside of the main forward hatch. A Cannon Uni Troll 10 downrigger can be fitted to a mounting plate I’ve installed on the starboard side transom (this should come in handy in the trout lakes and also for estuary downrigging for jewies and XOS tailor) and I’ve set-up two Scotty adjustable rod holders (again mainly for my planned trout trolling expeditions) to the aft side rails port and starboard.
Over the past year or so I’ve enjoyed some fantastic estuary sessions in the little Sea Jay catching bream, flatties, bass, jewies and EPs in my local waters as well as further down the coast around Narooma and Mallacoota. The opportunities this style of boat allows in regards to visiting other regions to target species as diverse as trout, cod, barra, yellowbelly, saratoga are front and foremost in my mind. All going to plan, I’ll hopefully be embarking on some interesting road trips in the not-too-distant future. Stay tuned …
Jim Harnwell wishes to gratefully acknowledge the assistance of Sea Jay Boats, Yamaha Australia, Humminbird, Minn Kota, Pro Alloy trailers, Cannon, Scotty and Garmin in organising and fitting out this project boat.