See full version: Offshore vessel ship designs
The first of our advanced UT 754 WP vessels, featuring our wave-piercing bow, has entered service with Farstad Shipping. Developed by working closely with Farstad and the classification society DNV, the UT 754 WP has been designed specifically to meet the needs of offshore vessels carrying hazardous and noxious liquid cargo. more
With its very large capacity for carrying hazardous and noxious liquid cargo and wave-piercing bow design, the UT 754 WP is a new direction for offshore supply vessels.
The average North Sea boat load of drilling mud and brine is 1,000 to 1,200m3. So, when the IMO changed the rules to classify mud and brine as hazardous or noxious cargo, usually limited to just 800m3, a new solution was needed to allow the desired amount to be carried per trip while still complying with the rules.
“Our wave-piercing bow designs have been specifically developed for the challenging conditions in which our customers operate.” here
On a motor yacht a fine angle of entry, say 12 degrees, is suited to high-speed semi-displacement style yachts, whereas a normal half-angle is between 18 to 24 degrees.
Bulbous bows are generally only found on displacement hulled yachts – that is, yachts that will not exceed about 1.5 x √LWL, or the Froude number for that hull. Marlow yachts, which are semi-displacement, have an option for a small, delta-shaped bulb that is flat on top and V-shaped below to both break the water and offer some resistance to pitching when performing above displacement speeds. (Bulbous bows work best when the yacht is moving at .9 to 1.2 x √LWL.) here
Designed originally to combat the waves off the Carolina inlets, the so-called Carolina flared bow is often attributed to sportfishing boats built by Buddy Davis and the others of The Outer Banks. The idea is that a fine angle of entry drives into the waves, but as wave size increases the flare rises up over them, throwing the water back into the ocean without getting the deck wet. more
Estonia's Baltic Workboats has announced that the first vessel of its new 15-metre aluminium wave-piercing platform has successfully been built, tested and handed over to customer - Estonian Pilot Ltd.
She has overall length of 14.95 metres and her maximum beam is 4,50 metres. Due to owner's request she also has a rescue capability with a hydraulic rescue platform in the aft of the vessel. Therefore special attention was also paid to keep her draft down at only 0,85 metres. Another focus was to re-design the whole wheelhouse windshield concept to maximise visibility and thereby add safety to the pilots’ dangerous working environment. here
Now named AHTO-14 she is the latest of Baltic’s very own designed wave-piercing series with, the company claims, top-of-the-segment seakeeping capability. more
ON THE WATER
Looking from dead ahead at water level, BWB’s wave piercing bow (Which the literature refers to as 'the wave impact reducing bow geometry with diamond shaped cross section') is a diamond shaped bulb, with the water level at rest slightly below the point of the diamond. The principle is that the buoyancy of the bulb combined with the gussets formed between the top parts of the diamond shaped cutwater and the rest of the hull, mean that the bow will find a roughly median position in the centre of oncoming waves or chop, rather than rising up, or trying to rise up all or most of the way over each wave, then crashing down, like a conventional hull. here
Baltic Workboats do Marketing in a big way. My attention was first drawn to their wave piercing bow design by a 3-D exhibit at SMM 2016 showing the (claimed to be appreciably lower) vertical accelerations of their bow versus a conventional one in a heavy sea. There is no denying that this was an extremely captivating exhibit for a trade show booth (it helped BWB win SMM’s award this year for the best technical showcase stand), but I think even management at BWB would argue that floating a video, in a black glass pyramid, apparently suspended magically in mid-air, is something of an attention grabbing gimmick. more
For our test drive of this 15m wave piercing pilot boat we had a fairly flat water day, due to an exceptional Baltic autumn heatwave. However, with shallow water, careful (or perhaps careless) treatment of hull tabs and throttles, and some sharp turns, we soon got just what we wanted: 1-1.5m of nasty, sometimes breaking waves, from multiple directions. here
This magazine deals with and is aimed at a great range of maritime professionals, but one group that have always inspired my greatest respect are the crews of pilot boats. They endure long shifts at sea in all weathers in relatively small craft, followed by intricately calculated risk-taking during boarding and ultimately massive levels of responsibility during the piloting operation itself.
The experience with the wave piercing bow once the whole of the boat was in the same chop was that it found a position somewhere in the middle of the waves, and seemingly locked onto it with the existence of the chop only betrayed by a slight wavering up and down from dead flat. [links]