New JL Ocean Raceboard in the offing

[coldsup]

this is a 25 wide version apparently.....look forward to some reports on bigger versions!

[Area 10]

In my humble opinion, that tail might be a mistake, in terms of both width and the sloping rear leading to a sharp edge. If you haven't got the rocker and volume distribution absolutely perfect, it is gonna act like braking on a skateboard.

[yugi]

^^^ huh?

Can't imagine how you get to that. With proper trim water will flow straight out from hull, not touching nor affected by the upper shape.

I'm happy to see a squared tail. Looks like plenty of volume underfoot (hard to tell). I like a tail that thins out like that. On a ride with tail slightly buried water flowing over the thinned out section tends to stabilize the board.

The outline looks v cool.

[baddog]

Very All Star'ish

[Area 10]

^^^ huh?

Can't imagine how you get to that. With proper trim water will flow straight out from hull, not touching nor affected by the upper shape.

I'm happy to see a squared tail. Looks like plenty of volume underfoot (hard to tell). I like a tail that thins out like that. On a ride with tail slightly buried water flowing over the thinned out section tends to stabilize the board.

The outline looks v cool.

Thin tails like that are easy to have water wrapping round, as you say, and that slows you down. And the lack of volume means that trim has to be just right or you have a knife-edge lancing into the water causing drag behind you. This is good for buoy turns but can be bad e.g. going upwind in my experience.

Just line up any of JL's flatwater boards against any of e.g. the SIC ones and then watch the extreme tips of their tails as they go past you at race pace. There tends to be more movement of the tail down into the water with the JLs under power. You can actually see the drag this is causing IMO. Some of that is the rocker line, probably, but I don't think these knife-edge tails help.

[PonoBill]

Straight rails help a lot. Squared tails often look more turbulent, but absent some turbulence-inducing mechanism probably aren't. I'd be concerned about water wrapping up on the tail, that could induce drag.

It takes energy to make turbulence, but a lot of the separation drag can't be seen. Pintails look super smooth, but the curve the water a lot, and that takes energy. Some of the turbulence caused is underwater. Square tails churn the surface, but penetrate less and the flow off the rail goes straight back. Six of one, half dozen of the other. For a very long, narrow hull a pintail works fine, for shorter ones if's probably not great.

[Area 10]

I wasn't arguing that wide tails are inherently bad, only that if you have them you need to get the tail rocker perfect or you have a large surface area to create drag. IMO Jimmy's previous distance boards (except the M downwinders) have tended to drag their arses, and be hard to get good trim on.

Mind you, I doubt that the current vogue for wide tails is done for good hydrodynamic reasons. It will partly because you can keep the rails more parallel so make tracking easier, but largely because of the increased stability: people now think that unless you are on a 23" wide board you can't do well in a race. But most people can't balance a 23" wide pin-tailed board in anything except flat calm conditions. I was amazed to watch a video of the Lost Mills race, held in mirror conditions, and as soon as the race started a load of people fell straight in, almost in unison, as the water churned up!

There have been quite a few really narrow-tailed SUPS. For instance the Ace and the K15. Both those boards are surprisingly fast in flat water considering their other characteristics. A part of that, which you can almost feel when you paddle, is the lack of drag from the tail, especially in response to pitching as the power is put down. This is probably why most fast kayaks etc tend to have narrow tails, not big fat square ones like many SUPs.

[Bean]

So, we know square tails are more efficient at planning speed while pintails are more efficient for displacement speed.  But as Jim K eluded to above, we need to look at the whole picture including the capacity of the paddler (the motor) and the conditions.

I look at some of the paddlers that have had incredible success on planning style boards like Fanatic's Jake Jensen and Infinity's Slater Trout, they have the motor to keep their boards on plane in conditions that would necessitate displacement boards for the rest of us mortals.  I'm starting to think that aside from down-wind conditions, planning boards probably do not make sense for the average recreational paddler.

[PonoBill]

Good point Area, I'm surprised that no shapers have tried a hybrid tail. Fairly easy to add enough rocker to hold the wide tail lightly on the surface, providing straight rails and stability while a pintail shape sits under it. I saw that in a rowboat that was designed around the turn of the century. Hard to make in a wooden boat, but easy in foam and carbon.

Almost all planing boards "drag their tail". Paddling a Bullet 17 with a semi-pintail in flatwater is pure pain. When you put enough rocker in to lift the nose when you run back, you automatically apply the brakes.

[coldsup]

You guys are too technical for me.....I just wait for others to ride them and give the boards a thumbs up or not