Planing Hull vs. Displacement Hull?

[Woody]

Not meaning to jam up the forum but I feel this deserves its own thread for my education. As I absorb the great advice from the many experts in the forum along my journey to acquiring my first downwinder, I discover more fundamental questions that need clarification.

Would you please help steer me towards a planing hull or displacement hull?

Cheers!

[paddlejones]

Here is a great comparison.

http://www.standuppaddlesurf.net/2010/02/27/bark-sup-and-sic-sup-race-board-comparison/

Thanks to Evan 

[Dwight (DW)]

A displacement hull should always beat a planing hull, until the planing hull planes up.

You can't paddle onto a plane without help from outside sources, like waves or wind.

The choice should be easy now. 

[Dugman]

There is a good video on You Tube with Mark at SIC explaining the two boards. When I find it I will ad to this post. He says that a displacement hull is great when water is flat and wind is below 12 knots. The planing hull works best with a 15 knot or more wind and some waves pushing. My limited experience tells me to get a planing hull for the strong down winders here on Maui. If I lived in Florida or some place calmer I would get a displacement for sure. I heard some were that Naish will be coming out with a 14 foot displacement in addition the there planing hull they carry now.

[1paddle2paddle]

I believe the use of these terms as mutually exclusive is an oversimplification.  A "planing" hull, when not on plane, is displacing (water); a "displacement" hull, when moving fast enough on the water, becomes a planing hull.

I understand the use of the terms is the idea as to what the boat is primarily designed for.  "Planing" hulls are primarily designed for situations where you will be able to go fast enough, typically on a downwind run once you have caught a wave, to plane over the water and, in effect, be surfing.

If you are primarily going to be paddling flatwater, the increased rocker of the downwind ("planing") board will actually push some water in front of it and slow the boat down.  Thus, flatwater boats are usually made with less rocker.

[paddlejones]

more on the subject...

http://www.standuppaddlesurf.net/2009/07/21/s-i-c-f-18-full-displacement-sup-race-board-vs-f-16-video-with-mark-raaphorst/

[PonoBill]

I believe the use of these terms as mutually exclusive is an oversimplification.  A "planing" hull, when not on plane, is displacing (water); a "displacement" hull, when moving fast enough on the water, becomes a planing hull.

I understand the use of the terms is the idea as to what the boat is primarily designed for.  "Planing" hulls are primarily designed for situations where you will be able to go fast enough, typically on a downwind run once you have caught a wave, to plane over the water and, in effect, be surfing.

If you are primarily going to be paddling flatwater, the increased rocker of the downwind ("planing") board will actually push some water in front of it and slow the boat down.  Thus, flatwater boats are usually made with less rocker.

Mmmm, no. Well, yes and no. You can look at either of these t6wo downwinder hulls and immediately tell which is wich, without looking at rocker. Planing hulls look like surfboards, displacement hulls look like canoes.

[CMC]

Hey Woody, I just spent months researching this from almost every resource imaginable to work out what I wanted.

For us here in QLD Aust, you want a board that does everything, runs in calm conditions on the ocean and flat water as well as also being able to handle surf to a degree as there are no calm ins and outs.  We also get strong open ocean winds and following swells so without being able to buy a quiver it is ultimately required to be everything.  Many races here also start in calm, have a rough ocean section, run through surf and then a flat water sprint finish.

If you think of a speed fishing boat, it has a displacement nose to cut through chop in the ocean, this same displacement also assists the hull to get past the speed required to lift the boat onto a plane easily where the nose is mostly irrelevant as it runs on the tail.  It really is the same concept with an ocean board, you want the nose area to be displacement to cut through chop without pushing back at you, help keep the nose above water when pushing into the swell in front when on runners and also to reduce pushing water in the flats and this same rocker design to allow the board onto a controllable plane with a little speed via wind, waves or ocean swell.

If you look at all of the bigger name DW or race boards for the ocean they all mostly have a displacement style nose flowing through to a planing surfboard type bottom, most even feature concaves etc.

[Woody]

Excellent video link PJ, it goes a long way towards understanding why I may want one hull design over the other. CMC, I also enjoyed your explanation for needing a design to handle varying conditions.

Looking out to the open water from my vantage point within the local line ups in North County San Diego, my first instinct would be geared towards grabbing a DW shaped more towards knifing through the bumps vice catching larger open ocean swells. My intention is to enjoy 5-10 mile paddles up and down the coastline where we typically find light off-shore winds in the morning and on-shore till the evening again.

Are there any SoCal paddlers out there with info on what you’re paddling? How its working for you?

Cheers!

[DavidJohn]

I'm not into displacement hulls unless it's just for rivers or lakes with no real runners... If it's runners that you're into I think planing hulls are the way to go for sure.

For me it's all about getting on the plane and surfing the bumps and not just surging along in the way displacement hulls like to cruise.. even if they are faster.

DJ

[greatdane]

Perhaps I am re-stating what has already been said...

Just for the sake of argument.... most "displacement" hulled SUP's are only "displacement" hulled for the first 25% of the board.  For example, the Starboard Pin and the Bark that I have.  The first foot to 3 feet of both boards look like "canoes".  Beyond that they look just like the Starboard Whopper (although narrower).  Same flat bottom.  Similar rails.  Once on a runner, I step back a foot or two or more on the Bark and the displacement properties are gone and I am planing.  The "canoe" nose is no longer doing anything.  Then when I am on flat or choppy water, the nose is doing it's job by slicing through and not slapping-over. 

If I take a surf SUP and mold-on a canoe-like bow... does it automatically become a displacement hull... doubtful.

Why don't surf skis and OC's have "planning" hulls & tons of rocker if that is the most efficient thing on runners?  Perhaps this is just comparing apples to oranges. (Also they are 16-18" wide)

I don't have the answers or the knowledge... these are just observations...

[Woody]

Great points GD. The video (5 posts back) with Mark Raaphorst of SIC has a great piece in it about the challenges of transitioning from a canoe displacement type shape into the flat planing hull. Some of the challenges arise from the width required to provide a platform not too tippy to stand on as well as giving the board a flat bottom surface early enough to allow for it to plane at higher speeds.

One of the significant things I have learned through all of this when considering my first DW, I feel I really need to look hard at the conditions I will be paddling in most and what I hope to achieve with this first hull. For me, I’m looking for a good all around hull to cut my teeth in DW with that is best suited for SoCal conditions. I don’t believe I will see the size of rollers Bill and DJ see on a daily basis in Maui (perhaps I’m wrong), but I also can’t ignore the fact that many of my exits will be re-entering through the breaks, so I need to feel comfortable with its handling on smaller waves. Regardless, I will be testing both hull designs.

Again, my assumptions are just that, assumptions from what little I know about DWing and the off-shore conditions in northern SD. I think I’m going to go pay a visit today to Jeff at Legends Surf in Carlsbad; he has the local experience to take me the rest of the way.

I’ll make sure I share his wisdom with the forum.  I’m in no means declaring this thread closed; keep the comments coming!!!

Cheers!

[StandUpPaddleSurf.net]

Here is a great comparison.

http://www.standuppaddlesurf.net/2010/02/27/bark-sup-and-sic-sup-race-board-comparison/

Thanks to Evan 

Thanks PaddleJones!

Woody - It's pretty hard to segment btw a planing hull and displacement hull bc they are mostly all combinations of both, although some pull more toward one end of the spectrum.  I think it may be simpler to determine what conditions you'll ride in and what you want to get out of it, because once you also have other considerations like length and rudder.  Nowadays the race boards are pretty condition specific.  You can ride them in different conditions but they work best in certain conditions.  e.g. under 15 mph wind normally means knee high bumps and the F-18 can catch and connect bumps much easier than the F-14 or F-16.  In 30 mph wind (like this week on Oahu), the F-14 and F-16 are way more fun than the F-18. 

Isn't Northern SD mostly light winds and small swell?  If you have winds under 15 mph and swell that is lower than waist high then a planing hull with lots of rocker is going to take a lot more effort to paddle than a displacement type hull.  Actually, in conditions like that, the S-16 catamaran would be really fast. 

It's all personal preference.  Yesterday, I tried my friend's custom F-14.  I was a little bit slower in overall time on it than the molded F-14 but I had the best time on it.  It felt like I surfed the majority of the run. 

[PonoBill]

As our friend Mr. Kaweeka so rightly said, the fast way isn't necessarily the fun way. I find when I paddle with even one other person I concentrate on going faster because I don't want to be last. I don't have to be first, but I don't want to be last.

When I do a solo run, I take a lot longer, and I spend most of my time in a swell. How can that be slower? Simple, I don't care where I'm pointed as long as I'm gliding.

I've spent a fair amount of time on the open ocean in SoCal--not on a SUP: Racing catamarans, windsurfing, and open ocean swimming. It's generally consistent but light wind, even a Santa Ana wind is a light breeze compared to the Gorge or a good Maui Trade. But there's a lot of fetch, and the swells get pretty decent once you get away from the many breakwaters and points.

As several people have mentioned, there are very few full displacement hulls. The Penetrator is about the only one I recall seeing. Most of Mark's designs have a flat area towards the back and some tail rocker. When you get them into a swell they slide a little sideways until you crank the nose up, then they surf the swells just fine. I rode my displacement hull F18 in 45 knot Gorge winds last fall, riding some very big swells. It tossed me off a bunch of times until I learned to shuffle back to the tail and stay there until the music stopped.

[1paddle2paddle]

Why don't surf skis and OC's have "planning" hulls & tons of rocker if that is the most efficient thing on runners?  Perhaps this is just comparing apples to oranges. (Also they are 16-18" wide)

Good point to bring up.  A few years back when I was deciding which surf ski to purchase, I was comparing the Epic V10 to the Mako ("6" I believe).  They were both 17" wide, but the Mako had more rocker (basically nose & tail).  The Mako was easier to turn and maneuver in the smaller bumps, but when the seas got bigger and more confused the Epic's stability was greatly appreciated, even though it did not "surf" the smaller bumps quite as well.

For surf skis, since a significant part of the racing is done on "flat" water, you need a boat that is as fast as possible in the flats, and you give up a bit of "surfability" for that.