“This project video shows the process from design to sea trials of a Hull Vane retrofit on the 52 m Offshore Patrol Vessel Thémis from the French Affaires Maritimes. The installation was done by CMN Cherbourg, which was also the builder of this vessel (delivered in 2004).”
I have posted on this particular innovation before, twice in fact, in 2017, “Hull Vane Claims Improved Performance,” and in 2015, “Hull Vane on an OPV,” but now we have another example and new information. This time the example is a mid-life up-grade on a vessel slightly larger but otherwise similar to the Webber class WPCs, the OPV Thémis from the French Coastguard (Affaires Maritimes) 409 tons, 6,310 HP, 52.5x9x2.27 meters (172.2×29.5×7.45 feet)
MarineLink reported this experiment, but I also found an excellent report with more photos here.
The results of this trial:
Comparison with the benchmark sea trials – conducted in January in exactly the same conditions – by CMN’s sea trial team showed a reduction in fuel consumption of 18 percent at 12 knots, 27 percent at 15 knots and 22 percent at 20 knots. The top speed increased from 19.7 knots to 21 knots.
The earliest post, “Hull Vane on an OPV,” reported the effects of applying the innovation to a 108 meter Dutch Holland class OPV, a ship very much like the Offshore Patrol Cutter (OPC).
- They claimed a 12.5% reduction in fuel consumption, overall. Specifically they claimed. “…runs were done to determine the resistance at 5 knots, 12.5 knots, 17.5 knots and 22.5 knots, showing resistance reductions of 1.3%, 13.7%, 15.3% and 11.1% respectively.”
- A 4% reduction in heave,
- A 7%% reduction in pitch, and
- A 13% reduction in vertical acceleration at the flight deck.
A comment on this earliest post, received from the Hull Vane team, noted.
“The performance is better however on the fuller-bodied and wider-transomed hull shapes like the typical US Coast Guard cutters, which we would very much like to do some work on.”
The Hull Vane web site has a number of publications, testimonials, and case studies, including a Nov. 2017 report on a 25 meter patrol boat. that claimed a 20% reduction in fuel consumption. It also noted “RPA 8 is the eighth vessel to be equipped with a Hull Vane®, and ten other ships which will have a Hull Vane® are currently under construction.”
As the new ships enter service, we will probably see the Webber class using more fuel than the 110s, and almost certainly the OPCs will use more fuel than the 210s and 270s.
I would think we would want to check this out, starting with contacting the Dutch Navy and the French Affaires Maritimes to get their take on the tests. Did they think they were successful? Are they going to use Hull Vane on their own ships? If not, why not? That would cost us very little. If the responses are positive, it would make a great R&D project. Bollinger might welcome the opportunity to try one out on a new construction Webber class. The baseline capabilities of the class are already well documented.
Impressive. I hope the USCG pays attention and implements this innovation!
How does this compare to a hull flap which have been around for years and has the advantage of structurally being part of the hull?
The hull flap, as I understand it, counters the squat we normally see when a vessel is proceeding at speed. They push water down so that the stern rides higher. They are claiming this does that but also has other effects including a lift vector with a forward component.
The 108 meter OPV study (a paper study) compared the system to a baseline vessel equipped with a trim wedge that would have to have been removed to make the hull vane work properly. More here. https://www.hullvane.com/wp-content/uploads/2017/01/FAST-2015-A-Life-cycle-Cost-Analysis-of-the-Application-of-a-Hull-Vane-to-an-Offshore-Patrol-Vessel-1.pdf
You might want to look here: https://www.hullvane.com/tech-talk/
I don’t know if this really works, but it should be fairly easy for the Coast Guard to contact the French and Dutch and get an honest appraisal.
Hi Johnno, there are three main differences:
1. A hull flap gives vertical lift as well, but this is angled backwards. The lift generated by the Hull Vane is angled forward (providing forward thrust).
2. A hull flap increases your immersed transom area, which is bad for your resistance at low (patrol / transit) speeds. A Hull Vane increases your wetted surface area, which is also bad at low speeds but this penalty is much less than that of an deeper immersed transom.
3. A hull flap will create much more reverse wake and wake turbulence than the Hull Vane. This means more noise and also more difficult launch & recovery of daughter craft.
Then there are other differences, such as the fact that the Hull Vane starts “pumping” when the ship is pitching in waves, generating more thrust. It also dampens the pitching motions more than a stern flap does (good for helo-ops en ribs L&R).
So, increase in top speed, greater savings in fuel economy, and better ride (which has implications for helo ops, rescue ops, and crew comfort – particularly in storm seas). Almost sounds too good to be true, so yes, it would be interesting to hear what the French and Dutch think.
Another aspect which I haven’t seen mentioned yet, is ASW stealth. It’s not going to make a surface vessel undetectable, but with the way it smooths the wake, I wonder if it will reduce detection range of the vessel, and possibly improve hull-mounted or towed array performance due to less interference from the vessels own noise signature?
Dutch Marine Police using Hull Vanes on six patrol boats. https://www.marinelog.com/technology/damen-to-fit-four-more-patrol-vessels-with-hull-vanes/
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