Volvo reverse bow: coming to a boat near you?

[Jackdaw]

Unlike the very useful plumb bow that now widely seen on production boats, the reverse bow of the new Volvo 65 is a mostly cosmetic feature. Even so, many think it looks cool. Do you think it will appear on a production boat? If so who will do it first?

 

[njlarry]

Looks like fashions return. That was popular a couple centuries ago. Remember the Maine? IMHO neither seaworthy nor graceful looking but maybe techy types will go for it.

 

[woodster]

i always thought the bow was supposed to lift the boat not make it dive deeper in the water ..... as far as looks are concerned i don't like it but it may be so that the water line for the hull is longer or something maybe to do with the rules or what ever i just know i don't like it

as for your questions ...yes it will be on some production boat ...as they are always trying to re invent there selves as for who most likely the french or nz's but my guess is the french

 

[RichH]

1.34 times the square root of the water line length.

Great idea, and simply follows what the commercial maritime designers have been doing for the past 40-50 years.
Will underwater parabolic shaped 'bulbs' at the bow be next?


The overhanging bows ( and sterns) on common boat designs are only 'rule beaters' following archaic 'racing rules'.

 

[Jackdaw]

i always thought the bow was supposed to lift the boat not make it dive deeper in the water ..... as far as looks are concerned i don't like it but it may be so that the water line for the hull is longer or something maybe to do with the rules or what ever i just know i don't like it

Woodster, reserve buoyancy is what keeps the bow out of the water. That's freeboard and increasing beam.

If you want even more, you can add flare to the topsides. But that makes the bow lift violently when pushing through a wave. For performace it's better and faster to let the bow go throught the wave. It's faster and easier on the boat, but the people in the cockpit get drenched.

 

[RichH]

i always thought the bow was supposed to lift the boat not make it dive deeper in the water .....

Buoyancy is a function of volume, not shape. Within limits, if the bow shape has sufficient bouyancy, the shape really doesnt matter.
The reverse plumb bow 'stretches' the waterline length - a speed advantage by creating longer period waves along the hull; hence, faster hull by increasing its 'hull speed'.

Submarines running partly submerged with decks almost 'awash' are vastly faster than the same boat fully on the top of the water .... a function of 'surface tension' of the water and where most of the boat is below the 'surface' for less drag interference from 'surface tension'.

 

[RichH]

If you want even more, you can add flare to the topsides. But that makes the bow lift violently when pushing through a wave. For performace it's better and faster to let the bow go throught the wave. It's faster and easier on the boat, but the people in the cockpit get drenched.

I have a boat with severe 'flair' to the bow topsides. Its great for keeping 'dry' but will easily become stopped if the bow fully plunges into an oncoming wave. I prefer 'dry'.

An example of the the 'other extreme', my other boat has a sharp but wide horizontal 'blunt' bow (a big ILYA scow) .... its known as 'the submarine scow' and can easily sail itself underwater into the face of a big wave and 'pitch pole' if your not careful. Apparently several 'tons' of water on top of the foredeck isnt 'helpful'.

 

[Claude L.-Auger]

NJLarry mentions the USS Maine. Here is a painting showing her. And let's not forget that ship was built in the late 1800s ! The United States Navy is currently spending billions on new destroyers for its fleet. The Zumwait class ships look different from any other ship you may have seen. See pix attached. Finally, one the the most prestigious private craft in the world, the motoryacht A, built in 2008, 390 feet, reputedly worth $380M which I took a picture of while sailing off the coast of St.Marteen in February of 2013. While those lines come from the past, they are indeed modern and as RichH says, it increases the water line, while slicing better through the waves.

 

[Brian D]

Either Beneteau or Jeanneau will incorporate this "new" bow design into its upper class fleet.

 

[shemandr]

Do you think it will appear on a production boat? If so who will do it first?
Yes. Beneteau.

 

[RichH]

.......... it increases the water line, while slicing better through the waves.

Plus, due to the narrow width foredeck, but still the equivalent buoyancy volume at the bow, any water that lands on the foredeck is more quickly drained away.

 

[Jackdaw]

On modern powerboats and warships,this is called a ' wave piercing bow'. Handy.

On sailboats, there really is no function. Yes the waterline is longer, but then why not run the deck to the same length? Doing this allows the forestay to be farther forward, giving a bigger J measurement and more sail area.

The VOR65 was not designed to a rule, so there is no 'rule bending' going on. If Farr wanted the bow to be vertical, they could have drawn the deck 6 inches longer with no effect on the boat.

Under ORR or IRC, the ratings rule factors LOA (length over all), LOD (length on deck), LWL (load waterline length) and LOH (length of hull) to eliminate any rule bending. In the absence of being able to do this, all modern raceboats have vertical bowstems.

 

[RichH]

I dont really think your going to see such on mainstream cruising boats, charter fleets, and dockside entertainment centers.
This boat design is going to be quite 'wet' - imagine grandpa and grandma or novice charterers having their cockpit wine locker, cockpit canapé table and 'entertainment center' ruined by bow boarding waves .... and for the exact same reason all the beautiful and stunning 'tumblehome' hulls of the 80s really never caught on - they were 'wet'.

If ß, etc. starts to incorporate this design into their boats it will be very modified and very conservative .... probably just a 'wee bit' of reverse bow form and a lot of 'tumblehome' shape at the bow ... to 'look like' and give the visual 'impression' of the radical bow forms now starting to appear in the 'testicles to the wall' racing circuit.

 

[shemandr]

Dava390 posted this link on another thread showing Raggamuffin at speed:
https://m.youtube.com/watch?v=TsJewTrY5v0
I think it is a good visual representation of the points discussed above. Fast? Yes. Dry? No. I wonder how the sailers stay on the boat with all that water rushing down the decks.

Edit: JustSomeGuy actually gave the link on a thread by Dava390.

 

[Ken Prichard]

I don't know squat about the engineering but I think it looks cool. I could definitely envision it on a Beneteau First. Wish I had one.

 

[justsomeguy]

Dava390 posted this link on another thread showing Raggamuffin at speed:
https://m.youtube.com/watch?v=TsJewTrY5v0
I think it is a good visual representation of the points discussed above. Fast? Yes. Dry? No. I wonder how the sailers stay on the boat with all that water rushing down the decks.

Edit: JustSomeGuy actually gave the link on a thread by Dava390.

You mean "justsomegeek", right?

 

[Bad Obsession]

Gunboat did this already on their 60' cat. http://www.gunboat.com/series/gunboat-60/

I agree on Beneteau or similar manufacturer.

Still, I like the classic lines. Some of the blended boats look really good too, but I really don't like the ultra modern look.

 

[Jackdaw]

I dont really think your going to see such on mainstream cruising boats, charter fleets, and dockside entertainment centers.
This boat design is going to be quite 'wet' - imagine grandpa and grandma or novice charterers having their cockpit wine locker, cockpit canapé table and 'entertainment center' ruined by bow boarding waves .... and for the exact same reason all the beautiful and stunning 'tumblehome' hulls of the 80s really never caught on - they were 'wet'.

If ß, etc. starts to incorporate this design into their boats it will be very modified and very conservative .... probably just a 'wee bit' of reverse bow form and a lot of 'tumblehome' shape at the bow ... to 'look like' and give the visual 'impression' of the radical bow forms now starting to appear in the 'testicles to the wall' racing circuit.

Dockside Entertainment Centers.... I gotta remember that! ;^)

Fast and wet? Yes. Fun? My 50 year old grandmother/partner thinks so. But she's not typical. And I thank the stars for that!

 

[Anonymous 121765]

For those serious racers, topics in design change lend to great discussion & I get that.

That being said, we all sail in a liquid medium influenced by tides & the ever-changing dynamic known as wind. And, as we all know, wind influences wave action. Thus water is also dynamic.

So, is there a perfect design for a boat for all conditions? I would have to say no. I will add that one of the best designs I have experienced aside of the Volvo-type sled racers are, the smaller cruising/coastal performance boats fitted with a winged keel. I'm abit disappointed that this design fell out of fashion to be replaced by bulb keels. I've sailed my friend's Newport 30 in all conditions & wished my Chevy-designed C30 had one.

Please don't beat me up on this guys.........

CR

 

[Gunni]

The wave piercing hulls are increasingly popular on the performance cats (Gunboat, Balance) but then they are not concerned by the difficulty of deploying an anchor off the bow. They have a nice wide forward beam, a bridle and lots of room for a rode to move about without removing gelcoat. I wouldn't want a plumb bow for the same reason...and in the words of Jim Brown, bow sprits have killed more sailors than any other boat part, so give me a nice overhanging foredeck please.