What is Reverse Chine?

Brandon Yuchasz

Brandon Yuchasz

Well-known member
I understand soft and hard chine. I understand rocker and no rocker but when I am reading on the Banks Duck Boat site about the boats they make they keep mentioning the reverse tunnel chine (RTC). I assume some of you own the boats or at least have seen them and could fill me in a bit about whats so special about the design. I seem to remember mention of it allowing them to build a flat bottom boat is that correct?


 
I really have no idea, but I found this with a google search:


[font=Verdana, Arial, Helvetica, sans-serif][/url]Do reverse chines help with stability ?[/font][font=Verdana, Arial, Helvetica, sans-serif][/font]
[font=Verdana, Arial, Helvetica, sans-serif]Reverse chines do not improve stability at rest. [/font]
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[/url][font=Verdana, Arial, Helvetica, sans-serif]What exactly do reverse chines do?[/font]
[font=Verdana, Arial, Helvetica, sans-serif]Reverse chines direct the spray downwards and not outwards resulting in a dryer boat. Reverse chines add some directional stability to the vessel, similar to skegs on a surfboard. Reverse chines do not increase the wetted surface area and do not add to the drag of a boat. For example, a 100mm wide chine is still 100mm wide whether it is installed horizontally or on an angle. [/font]
 
It also allows a boat to get up on plane at a lower speed and with less horsepower as long as the boat is not too heavy.

The "wings" of the reverse chine capture water under the boat and compress it slightly which pushes the boat up off the water.
 
Interesting, Thanks for the responses everyone. Does anyone know how much rocker they put into the boats? I'm curious about the flat bottom claim yet being able to handle big water.

Another thought, has anyone tried to incorporate reverse chine into a stitch and glue boat or more specifically into a devlin boat design? Seems like it could be built up out of wood and epoxy.
 
Brandon, no clue on Bankes boats, never seen on in person.

I have however, seen the reverse chine on other Devlin like boats, works very well, like Ray mentions, you get on plane very nicely, oh, and you have VERY minimal wake.
 
Brandon

I am away from a computer today so I can't post pictures, but I'd say there isn't much rocker in my Bankes. The big water capabilities come from the bow design. The flat bottom and strong V bow marriage seems to work well. I have floated/hunted the 19 footer in 6 inches of water and also been through honest to goodness 3' foot (6 feet between crest and trough) rollers. You can see pictures at the Bankes website.

If you google Tolman boats I think you'll see how to build a plywood hull with reverse chines.
 
Interesting, Thanks for the responses everyone. Does anyone know how much rocker they put into the boats? I'm curious about the flat bottom claim yet being able to handle big water.

Another thought, has anyone tried to incorporate reverse chine into a stitch and glue boat or more specifically into a devlin boat design? Seems like it could be built up out of wood and epoxy.
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If they have a reverse chine they are not flat bottomed. There are commercial fishing boat makers up here that make a "gull wing" hulled heavy skiff for herring and salmon fishing operations. There is no dead rise to the rear, or no rocker. The gull wing is what also makes them stable on the seas.

The Tolman skiffs are S&G and have a reverse chine using a step cut into the frame and a piece of core plywood. In the latest Wooden Boat mag they report the winners of a small boat design competition from over the summer. The winner was a S&G console skiff with a reverse chine.
 
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