Reverse Bows

hooverspeed has something the same since some years.
i can find booking, hotels and car rent but this is the only picture?
thats what boatdesign means to the world i guess

 

Yipster,
The Hoverspeed boats are built by Incat here in Tassie. Go to www.incat.com.au for more pics..

 

Kvaerner Innovative Designs

Beauty is in the eye of the beholder. To my eye, reverse bowed Kvaener's "Super Liner 300", pictured below on http://foxxaero.homestead.com/indrad_038.html sure's got it.

Luc

 

Not pretty? We disagree.

http://www.sms-navy.com/SMS_Baden-ptbow-top.jpg

 

Reversed bows

Dear Sirs!

Glad to see that You all have opinions on reversed bows! The picture on the top, the red boat, is actually called ULSTEIN AX0X and was designed by me back in June 2003 (I work at ULSTEIN DESIGN in Norway, doing hulldesign and overall design). It is an Anchorhandling Tug Supply Vessel using diesel-electric propulsion. It has been an idea of mine since 1997 to use these bows commercially, and this boat represents a vision.

This week we actually launced a building contract for a boat using a reversed bow! It is called ULSTEIN AX104, and is somewhat different from the earlier mentioned boat. Check out http://www.ulsteindesign.com! We've tested it throroughly, and to You sceptics out there; it works like nothing else! It is not a wave piercer, but works more like a dolphin! I'm introducing a new volume distribution, different from what most people think, and we found lower speed loss in waves, lower heave and pitch accelerations, NO slamming, NO green water on bridge deck etc. We call the bow X-bow, patent pending. This boat also have diesel-electric propulsion using azimuthing thrusters, and also have a new safe anchorhandling system - SAHS, patent pending.

It's been a busy couple of years!

Br
Oyvind

 

Thanks for your reply Oyvind. I hope you don't mind me posting your design. I was just very intrigued by your design along with other designs with reverse bows. It is a definite shift in design philosophy and is very striking to say the least. I am interested in the development of these designs and the benefits gained. Thanks for filling me in on some of the possible benefits.

I was wondering though, how you can patent something that aready exists. I find patenting things like CBTF and reverse bows very hard to do as many versions already exist from the past and present. I understand that there is a lot of detail not mentioned. These sorts of patents can't be generalized, they must focus on specific design features. Anyway thanks for your insight and I look forward to seeing your ship launched. It may be the start of a new design trend. Who knows.

 

Reverse curve bows are very efficient at reducing the bow wave. Most all new with it ship designs have a subsurface bow bulb to reduce bow drag. High speed, + 40 knot, Catamaran ferries are equipped with them. If the "new" marine designers come up with more new hull improvements, they will have to pay royalites to the dead. Even the "new" Q E 2 has a massive bow bulb and makes almost no wake at any speed. ------------------------------------------------The only real possible negative would be lifting the bow fast enough in a strong storm at sea? I have never seen side by side data of the same ship run with each type of bow in storm conditions. Maybe USN carrier design has a set?

 

This VSV hull technolgy makes use of reverse bows, http://www.vsvboats.com/
in looking at some of the photos in operation, the bow disturbance wave appears minimal


...and then this catamaran's ugly reverse bows (in my opinion, of course I'm not a big fan of the over-utilized plum bows on cruising designs either)

1) http://www.victorinox.com/newsite/en/action/actiondetails/katamaran.htm
2) http://www.kkg.at/de/93/

 

My observation is based on logic rather than formulas etc, but I can imagine a boat of this design could travel into a large swell and experience very little motion. My reducing the rate of bouyancy gain, you would inevitably reduce the bounce effect. Any other hull would jump off a wave, I beleive a hull like this would dive into a wave and come out the other side with minimal effect on ride comfort. Not sure about efficiency etc... Cant imagine it would be particularly beneficial to efficiency.

 

Back in the mid-nineties Kvaerner Masa-Yards was working on a 225-metre Ro-Ro freighter concept that had the most radical reverse bow I've ever seen... http://www.masa-yards.fi/ but I can't seem to find that particular design anywhere.

The wave-piercing designs, which usually incorproate a reverse bow to some degree, run faster with less pounding and heaving than a regular hull. Some claim that a monohull like the red one above, or the RoRo225, with a reverse bow extending all the way to the bridge, is more seaworthy than a conventional bow (if you stuff the bow into a huge wave, the boat cuts through it rather than taking on water). But for most applications the tradeoff in reduced deck space and hull volume isn't worth the higher efficiency and whatever unknown seakeeping abilities it may give.

 

Oyvind,
Congrats on getting your ugly mug on the front cover of Maritime Reporter! Almost life size, too.
Steve

PS - nice bow....

 

Look at a picture of IDEC or SODEBO.

 

Powerboat reverse bow can look good

Interesting reverse bow megayacht by Feadship:

During the launch ceremony at the Koninklijke De Vries yard in Aalsmeer (NL) on 5 January 2008, all eyes were on Predator’s sensational reverse bow. This bow forms part of the aggressive new styling brief at the core of the client’s wish-list. “The owner arrived at the yard in late 2004 with a request that we partner on something different than anything else afloat,” comments Henk de Vries. “Together with De Voogt Naval Architects and Bannenberg Designs (interior), we have created a super-sleek and highly sophisticated yacht that is genuinely innovative.”

http://www.yachtforums.com/forums/y...launch-feadship-72m-reverse-bow-predator.html

 

Reverse bow benefit

"By sweeping the bow backwards from the waterline, up… an oncoming wave encounters less resistance in contrast to a conventional forward-flaired bow. Essentially, an oncoming wave washes over the top of the deck and dissipates, as opposed to being displaced outward by a conventional bow." from discussion of Blohm & Voss's Sigma, an even more radical design, whose reverse bow's visual impact is matched by a unique superstructure.

http://www.yachtforums.com/forums/y...72-new-launch-blohm-voss-118-meter-sigma.html

 

You need more than just a big yacht to impress folks these days ...

Still another reverse bow megayacht, this one from Lurssen, designed by Igor Lobanov:

http://www.superyachttimes.com/editorial/5/article/id/1102

Why these radical designs? Well, it seems that boredom is setting in among the super rich. In fact, according to Mr Lobanov, "No longer is a 130m yacht so unusual or so impressive."