By Thomas P.

The first Mar.co twenthrytee may have launched in the water in 2000 for the first time, but still continues even today to be one of the most remarkable rigid inflatable boats which is worthily at the top of its class, constituting an inspirational model and an example to be imitated by many manufacturers.

MAR.CO Twentythree

Mar.co 23 is built on a highly seaworthy deep V hull that allows it to ride soft and dry even not under the most favourable weather conditions.

The sharp entry of its bow and the absence of a flat pad at the hull’s aft-most part, a technique that is followed by many Italian manufacturers who are pursuing more lift and higher speeds, indicate that the Mar.co boatyard adopts a clear offshore orientation for the design of its hulls.

We know very well that when a hull runs on a steep angle of V it creates much less lift than when running on a flat pad, which means more hull’s wet surfaces.

More wet surfaces means more drag, and therefore lower top speed and the need of more power.

On the other hand, when the hull runs on its steep angle of V offers improved ride and softens our navigation in rough seas.

As it has been pointed out many times, unfortunately, in the world of the sea we can not have it all.

MAR.CO Twentythree

There is no hull that could do it all.

Taking into consideration that most of the time our ribs are operating at speeds of 20-35 knots, as well as that the sea is not always flat, it is obvious that is not worth sacrificing the softer and more comfortable ride for a few knots of higher top speed, except of course if we usually run in lakes.

From that point of view, I find the Mar.co’s designers orientation quite wise for whom the high speed is not the objective.

On deck

Over the years, the deck of Mar.co 23 has undergone several improvements and changes, the more recent ones of which involve redesigning the swimming platform and console and it seems the manufacturer did his best offering the maximum for such a single rib.

MAR.CO Twentythree

It features one of the most spacious decks in its class, which combined with its ergonomic design and the really inspired solutions, provides all the comforts even to its most demanding prospective owner.

One of the most distinctive features of Mar.co 23 is the very wide hard nose which is applied on the front part of the tubes and provides comfortable and safe entry and exit from the boat.

For the same reason, the anchor is placed under the tubes emerging from the opening at the bow entry.

Notice also, how beautiful the cleats are mounted on the front surface of the hard nose, leaving completely free its upper surface without any danger of injury when boarding.
In the bow superstructure we distinguish four separate cushions which correspond to various independent lockers, the front of which is smaller, constituting the place where the chain of the anchor is stored and the windlass is positioned.

MAR.CO Twentythree

The right one of the other three lockers is oblong, ensuring the proper space for the storage of long objects such as paddles and spearguns.

The length of the bow sundeck reaches 1.94 meters and its maximum width is 1.36 meters. Although its dimensions are able to comfortably accommodate two adults, we can still increase it more by placing the appropriate extension, which of course will not be found in a locker consuming useful storage space.

One of the smartest ideas that have inspired the designers of Mar.co, is to install the extension of the bow sundeck on the floor, between the console and the driver's seat so beautifully located that it can’t even be noticed.

MAR.CO Twentythree

MAR.CO Twentythree

The helm seat is a double bench with rotating backrest, which when turned in front serves the upright driving position while also forming a double aft-facing seat, increasing this way the number of seated that can be gathered in the aft lounge.

If you believe that in a rigid inflatable of 7.40 meters there is no free space to place an outdoor kitchen, you are probably wrong.

aising the driving seat the wet-bar of the rib is revealed, which can be fully equipped with a sink, a stove and a refrigerator.

The redesigned console is particularly sleek and centrally positioned leaving comfortable passageways of 33 cm width; while on its front side a wide seat is integrated.

MAR.CO Twentythree

The instrument panel has the appropriate space for the installation of even large navigation devices and has the right inclination to provide comfortable visibility even when driving.

MAR.CO Twentythree

Behind the helm seat there is the aft lounge, which is formed in the shape of the Greek letter of «Π» and constitutes the main gathering area of the rib. It can comfortably accommodate 6 people, while with the proper extensions it can quickly be transformed into a large dining area or a spacious sundeck.

MAR.CO Twentythree

MAR.CO Twentythree

The polyester roll bar, which is reclining and allows it to fall forward when parking conditions require it, has very useful sockets for storing emergency equipment.
To its port and starboard it leaves easily accessible passageways for our fore and aft movement, which in our test rib were lined with synthetic teak.

On the back of the aft sofa there are the known and very useful cabinets for the reception of the shower wand and the water’s tank intake. Between them, we can see a remarkable and wonderful solution for the storage of fenders, which do not only fill a locker but they are very easily accessible too.

MAR.CO Twentythree

The particularly large swimming platform, which is well-designed and is one of the strongest points in every rib of the company, extends to the right and left of the engine, offering not only a comfortable space for easy access to the deck but for our sea activities too.

Indeed, we were very impressed by the wonderful patents of the deck, which greatly facilitate our living on board, while taking advantage of every inch of its free space.

Under no circumstances will we find any defect or area that is not designed in the most ergonomic and intelligent way, no matter how we thoroughly inspect.
That's why I'm sure that there will be soon a way for the ladder to find the proper position it deserves on such a high-level rib.

At Sea

On the transom of Mar.co 23, the brand new 4.6-litter V8 300hp Verado was hung, which is 16 kg lighter than the previous Verado 300 generation, promising higher torque at low and medium rpm as well as stronger acceleration.

MAR.CO Twentythree

Having a 4-blade 14 5/8" x 19" Revolution propeller on the 300hp Verado’s propshaft, which is turning with a 1.85: 1 gear ratio, I turned the bow to the open sea and, pushing the throttle forward, I was trying to get a first feeling of the 4.6L’s power and the 7.20 meter Mar.co 23 hull’s response in this new set-up.

What was, of course, instantly perceived was the smooth and quiet operation of the engine, especially at the midrange rpm, which allowed us to hold a nice conversation without raising our tone of voice.

With 250 litters of fuel in the tank and 4 people on board, the rigid inflatable was standing on plane at 2400 rpm, maintaining a constant speed of 12 knots.

At 3000 rpm we gained another 6 knots burning 1.27 litters per nautical mile.
This was the most economical cruising speed we recorded, while at 3500 rpm the GPS showed 23 knots with no significant difference in fuel consumption, since we were now burning just 0.3 litters more.

By pushing the throttle a little more, the engine reached 4000 rpm and we were running with 29 knots, consuming 1.34 litters for each nautical mile.

MAR.CO Twentythree

At WOT, the engine spun the prop up to the upper limit of its recommended range and very easily we reached 45 knots without really insisting with its trim.

The fuel consumption at the full throttle was 94 litters per hour, while it is worth noting that we did not feel any signs of chine-walking because the hull is running on the spray rails that end up at the transom.

You can find our detailed data on the following table:

Perfomance data by  e-Ribbing pdf

The above figures are obviously quite excellent, if we take into account the weight of the rib, and especially the entire length of its hull, which is longer than any other in its category, measuring just 20 centimetres less than the overall length of Mar.co 23.

The planning speed was amazing and ranged from 4.2 to 4.4 seconds, while the rib accelerated from 0 to 30 knots in just 7.2 seconds.
At the midrange rpm, we were clearly feeling that the hull was standing high on the water, maintaining an almost level ride attitude, while the throttle response was very good.

The handling of Mar.co 23 was very good, as well as the quality of the ride, the main feature of which was the comfortable and solid navigation at cruising speeds.
When I was heading into our wakes, maintaining a speed of about 30 knots, the hull made it easy to soften our short landings, while the absolutely robust ride of the 7.40m rib was an indication of its excellent construction’s quality, a feature besides all ribs of the Mar.co’s shipyard are famous for.

It is worth noting that one of the main features of Mar.co 23 is its high and almost vertical bow, which in combination with its sharp entry plays a very important role in what we call as ride quality.
Substantially it increases the entire length of the usable hull which is «working» from far ahead, something we will appreciate, of course, when travelling in head seas which is the toughest kind of ride.
Then we will feel how smooth, the front part of the hull is able to penetrate the waves, softening greatly our ride, while the chine and the large diameter of the tubes will help the spray to be kept low, preventing it from reaching the deck.

MAR.CO Twentythree

The high and deep bow should not scare us when we are riding in following seas, because it handles the waves very well and seems to be easily controlled by the engine’s trim.
So, as we were approaching the backside of our wakes and we trimmed slightly out the engine, the hull was sliding easily up to their top without showing that there was a likelihood of stuffing the bow, despite its large volume.

Everything showed that the particular combination of rib-engine-propeller is a quite good set-up responding very well to every kind of ride.

MAR.CO Twentythree

If we want to work on this set-up trying to improve the performance even more, we have to focus on the relatively high slip percentage that ranged between 11% and 12% at 5500 and 6000 rpm.
Knowing that Revolution prop can provide much lower slip values and that it «likes» running near the surface of the water, it would be interesting to experiment with the engine mounting height, by raising it up one hole, thus giving the opportunity to the Rev prop to show its potential.

Of course, the greater low- and mid-range torque and better acceleration promised by Mercury, require the proper propellers to be seen in action. Maybe this was the main reason due to which we didn’t’ feel the extra benefit we expected from the 4.6-litter, eight-cylinder engine.
It is almost certain that the torque will become more noticeable if in our test set-up we fit an Eco Enertia propeller, which I think, except the engine characteristics, it matches better with the geometry of the particular hull.

So, it would be really useful to try a 16" x 18" Eco Enertia propeller, which will give us the same engine’s rpm at WOT as the Revolution 19" and will work better for our set-up.
Due to its specific features, it will get the rib on plane at lower rpm and achieve greater acceleration, while greatly reducing slip numbers will have as immediate consequence higher cruising speeds and reduced fuel consumption.

...keep Ribbing!

 

MAR.CO twentythree
  • Length overall: 7.40 m
  • Beam: 2.87 m
  • Weight: 930 Kg
  • Tube's diameter: 0.48 - 0.56 m
  • Fuel capacity: 300 Lt
  • Passengers: 14
  • Max power: 224 kW
  • Homologation CE: Category C

Manufacturer:
MAR.CO MARINE COSTRUZIONI
Via Edison 64, 20835 Muggiò (MB) Italy
Tel+39 0392787336
This email address is being protected from spambots. You need JavaScript enabled to view it.
www.mar-co.com

Boat Center

Representative of Greece:
Boat Center
59, S. Venizelou str., 14123 Lykovrisi - Attica
T. +30 210 28 49 507
www.boatcenter.gr