6 minute read
Speed@Seawork
BOATS @ SPEED @ SEAWORK
Jake Frith dusts off his post-Covid seaboots and experiences a range of high-speed craft in their natural environment
Eight boats were available at this year’s Speed@Seawork sea trials day, ranging from 50 knot+ military interdiction and troop insertion craft to one of the world’s most usable electric workboats.
As usual, a small but high-level set of delegates from all corners of the globe were there to take advantage of what is a rare opportunity – to see how boats from different manufacturers perform in open water with no speed limits.
Speed@Seawork, based out of Cowes Yacht Haven, has run three times now, I’ve attended them all, and I’ve never once managed to get out on all the boats in the course of the day. This year was no exception, but every boat I did sample in its own way represented an important milestone in commercial small craft.
Tideman Boats RBB700 EO 150
These tough HDPE (High Density Polyethylene) workboats are already well known to Seawork visitors. When Bruno Tideman takes a long-handled sledgehammer to the gunwale of one of his boats in Mayflower Park, all the exhibitors wake up, but there can be few more memorable ways to show how work-aday and tough a boat’s construction is.
While this electric version can push up to 35 knots, its range at that speed is best not discussed in polite company. It is powered by the EVOY 150hp (equivalent) electric outboard, which is an expensive but clever bit of kit with its permanent magnet synchronous motor providing 90kW continuous and 137kW peak power.
The liquid-cooled 63kWh battery allows for a five-hour range at ‘cruising speeds’ and it’s really intended for the Dutch canals, where they are serious about their speed limits and full compulsory electrification is due to come in by 2025 at the latest.
It is a planing hull though and it got up and going nicely through the Solent chop, but that capability will not be regularly utilised. It’s well suited to roles such as harbourmasters, who spend most of the time at a slow cruise, but might occasionally need a burst of speed to apprehend a miscreant or attend an emergency.
It can charge at up to 60kW, so about 1 hour with DC. AC charging is a more involved affair at 3.3 kW.
Fully electric boats are not cheap when it comes to CAPEX, but reduced OPEX claws it back. Tideman says that typical return on Investment break-even arrives within 2-5 years for commercial users.
SEAir FT80
I don’t think the other exhibitors would argue with my saying that the longest queues of the day were for a sea trial aboard SEAir’s hydrofoiling RIB.
In fact, the queues were mainly made up of the other boat manufacturers, deadly keen to experience this unicorn. Making hydrofoiling work at the scale of an 850kg 8m RIB, and achieving it with a reliability that allowed this boat to stay
8 Tideman Boats
RBB700 EO 150
8 SEAir FT80
on its foils in open water while hitting ferry wakes at all angles, is a laudable achievement in small craft design.
Since I last sampled a pre-production example, the foil control system has improved vastly, and it’s now a onebutton affair to tell the flight control computer to handle the foiling. After that, it’s a familiar set of controls – just steering and throttle. The computer commands servos that move the main (front) foils up to six times a second to maintain a consistent height. The foils partially retract for beaching, trailering and docking.
The point of all this is it offers claimed fuel savings of 2035%, and SEAir is also pushing the shock mitigation benefits of hydrofoiling, although we’d like to see the evidence on that side as it seemed no more or less slammy than most of the other boats we tried.
Turning hard is still not in this RIB’s repertoire. The natural tendency of a hydrofoil, because of its high centre of gravity, is to ‘lean the wrong way’ in turns. With that in mind we slowed down to 20 knots or so to complete all tight turns. SEAir are looking into reprogramming the flight computer to lean the boat into turns and this will likely greatly increase the appeal of the boat.
Ultimate Boats M-Class
Seawork had the honour of hosting the world launch of this new fully recyclable, high-performance workboat range.
This 11m vessel has just been commissioned and handed over to Police Scotland’s Dive and Marine Unit. It is built from a new fully recyclable composite material called DANU, which Ultimate Boats believes to be the most resourceefficient composite material available.
Police Scotland’s boat has a top speed of 50 knots and an operating range of 400 nautical miles. The boat is powered by twin Suzuki DF325A dual-propeller outboards.
According to our skipper, John MacAndrew, a Master Craftsman at Ultimate Boats, based on the Clyde, DANU is also universally popular with the boatbuilders because it uses an itch-free fabric that is much easier to work with than fibreglass, and the infusion-only resin makes building the boats a much cleaner job.
The boat does not feature the ubiquitous deep vee hull of most planing workboats of its size. Instead its designer, John Moxham, has created what he calls a ‘hydraulic lift hull’ in which a narrower than usual central hull is stabilised by twin sponsons. This creates two channels underneath, which absorb a lot of slamming, making for a plush ride. If my job entailed spending 10 hours a day in a workboat in open water, this one would be high on the list; it really was a very pleasant place to be.
The hull corners flat at speed like many sponsoned hull forms, but what is of more interest to commercial users is its very flat transition from displacement to planing. This suggests that the boat could be relatively economical to run at ‘in between’ speeds such as the mid teens (in knots), which are often useful speeds to travel at to fulfil commercial operations but encourage an inefficient nose-up attitude and burn tremendous quantities of fuel in more conventional hulls.
8 Ultimate Boats
M-Class
Zodiac Milpro SRA750 XL
This hybrid tubed aluminium hulled vessel is almost not a RIB.
The Duratane collar is half moon shaped in section and apart from their use as occasional fendering and perhaps to aid roll stability when stationary or emergency buoyancy in the unlikely event of swamping, the tubes don’t actually seem to do a lot.
But that’s not uncommon or a problem and the vertical sides they lend the interior of the boat do greatly improve interior volume and usability, leveraged even further by the fully tracked deck that enables a multitude of different deck and seating configurations and rapid switching between them.
It’s a military RIB first and foremost and one of the highest strength and durability, but it is also aimed at police interdiction, Search and Rescue and anti-terrorism work.
I’ve always been a big fan of Zodiac Milpro RIBs as they always seem to achieve a ‘hewn from the solid’ feel, and this was reinforced by a blast up the Solent at above 50 knots. It weighs 3.5 tons empty and was equipped with twin Mercury 300s, so it was always going to be sure footed. There might be lighter boats that would make a bit more use of its 600hp but the Milpro boats have been tweaked and optimised over many years to the point where none of its ergonomics, performance, high and low speed handling could be faulted.
8 Zodiac Milpro
