Top Line S 24 is not just an ordinary rigid inflatable boat. It has come to break down established theories and to make us review many of our regular views. It is very difficult to find another rib in its class that can stand worthily next to it.
- The deep-V hulls require more horsepower and demand a lot of fuel.
- The weight of a boat adversely affects its speed and increases fuel consumption accordingly.
- We can not achieve high speeds and at the same time have excellent ride quality in heavy conditions.
These are some of the theories that S 24 manages to break down and make us wonder, proving that the design of a hull can do «miracles».
The 7-meter S 24 is a heavy rib, extremely wide, with a very deep-V hull.
Yet, it can run at high speeds using relatively small horsepower engines, shows low fuel consumption and offers incredibly soft ride in really difficult sea conditions.
And of course numbers never lie. S 24 of Top Line reaches about 1,800 kg (with all the necessary equipment, 200 litters of fuel and two people on board) and has 3 meters beam (just like Corsair 33΄) with a 24-degree deadrise at the transom, while the sharp bow entry measures the incredible number of 60 degrees.
Despite the above disproportionate numbers, it can run with 50 knots having mounted on its transom just an 225hp outboard engine and travel with 29 and 33 knots at 3500 and 4000 rpm respectively, with a fuel consumption close to 1 litter per nautical mile.
The secret, of course, is in the very special hull of S24, which is the first stepped rigid inflatable boat made in Greece.
It is really quite interesting to take a very careful look at its hull.
It takes only a quick view at its bow to make us impressed by its extreme knifelike entry of 60 degrees, the sharpest of all the models of company.
Taking a look at a little bit back, we can notice the very special spray rails that are semicircular in shape, forming a kind of tunnel, not looking like the spray rails we are used to see in which there is an accumulation of mechanical tendencies in their corners.
In addition, the heavily semi-circular shape of the S 24 hull increases considerably their beneficial surface leading to increased buoyancy, while holding much water that is pressed down resulting in particularly dry cruising and excellent stability at high speeds in rough seas.
The deck of S 24 has a purely pleasure orientation, ensuring large storage spaces and spacious sundecks both on the bow and stern.
There are some nice modifications to the cockpit of our test rib, concerning the helmseats and the absence of the roll bar.
The large foredeck gives easy access to the rib, without any obstacles, since the cleats are placed on its side surfaces. Its interior space, which is accessible from the hatch on the starboard side, houses the windlass and the anchor chain.
The bow hyperstructure creates a large storage space and, with the corresponding addition, forms a large bed for two people.
The console has a built-in seat on its front side and is located to the starboard of the deck.
Its upper side is wider and it’s narrow at its base so as to ensure a great space on the side for the comfortable movement of the passengers.
The instrument panel has the space required for the installation of electronic devices, while the stainless steel rail that hugs the windscreen offers the necessary hold for the driver and co-driver.
The stern bench accommodates an individual storage space and forms a large sofa where four seated passengers can comfortably travel.
Just exactly backwards there is the sunbed of the stern, which is extremely large in relation to the length of the rib, underneath of which there is a huge storage area where the owner preferred to place the toilet of the rib.
The aft sundeck is a very large sun and sleeping bed, which can accommodate two adults with comfort, while on the right and on the left wide polyester platforms are formed that facilitate our transition to the engine and the ladder.
The bucket helmseats differentiate from those proposed by the company, are excellent and offer very good lateral support while allowing us to drive seated or standing.
They are supported on a polyester construction which, at the rear, forms a two-seater seat, raising very high the number of people able to travel seated.
The amazing soft ride, the immediate planning and the perfectly level ride combined with the large deck spaces are some of the key features of Top Line S 24, which continues to attract the looks despite the almost two decades since its first design and construction.
S 24 runs on the developed hull of the legendary R 23, which first appeared 20 years ago in the Corfu races, gaining the attention and admiration of the sea world for the pioneering design of its hull, which has won many distinctions in the offshore races of the Top Line racing division.
Built on the modified R 23 offshore racing hull, S 24 is a product of accumulated experience from Top Line's multiple races, geared to the needs of the nautical camping and the requirements of the Aegean Sea, as a unique set of unlimited capabilities for fans of speed and ride quality.
We tested S 24 with an Optimax 225hp two-stroke engine which is running at a 1.75:1 gear ratio and wearing a 15 ¼" x 20" Bravo I FS 4-blade propeller.
With 150 litters of fuel, 40 litters of water and two people on board, the rib was getting on plane at 2300 rpm with 15 knots.
These figures, of course, are not representative of the S 24 hull, which is able to get on plane at lower rpm with a significantly lower speed.
The propeller, with which it was running, because of its design features, is not the best for immediate planning having high slip values trying to "pull off" the heavy rib.
Still, it took us 4.5 seconds to get on plane and 10.6 to reach 30 knots.
From the moment we were on plane, it took only a slight adjustment of the trim to make the rib get the right ride attitude and run lightly in the water.
At 3500 rpm our speed was 28.5 knots with a fuel consumption of 1.07 liters per nautical mile, while at 4000 rpm we were running with 33 knots burning 1.12 liters per nautical mile. The slip values were 13.4% and 12.2% respectively, excellent figures for the particular propeller, which of course are due to the astonishing lift of the hull, mainly due to the particular design of its spray rails. In other words, with 150 liters in our tank and cruise speed of almost 29 knots, we have autonomy of about 140 nautical miles.
Although the engine was mounted quite high, the rib was running very high in the water, which is particularly obvious from the low wakes it leaves in its passage, which minimizes the drag due to the reduced hull surface that is in contact with the water, thus fully justifying low fuel consumption and exceptional acceleration even with 225 horses on its transom.
At WOT, the engine reached 5700 rpm, recording 49.1 knots of top speed, demonstrating an excellent set-up that allows us to load the boat further without the risk of dropping below 5500 rpm.
You can see our detailed measurements in the PDF below:
To sum up, we can say that S 24 is a pure offshore inflatable boat, the unique and extreme features of which’s hull, enable it to handle very well rough seas and run very fast, with great safety and comfort we have not met on another rib in its class so far.
Parodos Chr. Beka – 19004 Spata – Athens, Greece
Tel.: +30 210 6025 515