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Travis McGee · 26-09-2015, 06:08

Last June, while sailing in the Gulf Stream on the way from FL to NC, I had the opportunity to jump in the water with a Go-Pro mounted dive-plane while dolphins (porpoises) were swimming around my boat. A friend put together this youtube video from the dolphin footage combined with some dive plane footage shot in the Abacos in 2014.

Anybody can make a good dive plane from a piece of scrap plywood with a jig saw, even aboard their boat. All you need is clear water and a boat that can tow at a steady 2.5 to 4 knots, slower for kids and beginners, faster for strong divers.

https://www.youtube.com/watch?v=SXwN...ature=youtu.be

Travis McGee · 26-09-2015, 06:09

Here is the original 2014 video, minus dolphins.

https://www.youtube.com/watch?v=_h0d62zOgKw

Paul54 · 26-09-2015, 06:56

Wow! Awesome!

Cormorant · 26-09-2015, 07:02

I'd like to make one of those dive planes for my boat. Has Matt posted a template anywhere?

I think I could roughly knock one off just guesstimating dimensions and relative positions of the handholds and line attachment points . . . but if Matt spent 20 years perfecting it, I suspect that getting it just right makes a big difference.

Travis McGee · 26-09-2015, 07:30

Here you go. It's easy enough to describe it, so you can make one yourself.
Use 1/2" exterior grade ply. Thinner ply may crack at the tow-hole during hard steering.

18" fore and aft by 24" port to starboard is about right, but they can be larger or smaller if that's the ply you have on hand.

First find the center of the board. The tow hole will be about an inch in front of the center. In the videos, the rope slot is straight, with parallel sides in front of the tow hole. In my newer versions, I open the rope slot up into a "V" to give the tow rope more latitude for steering without catching on the board. You need about an inch of ply in between the tow hole and the rope slot.

About an inch behind the center line, mark off a side-to-side line for your finger slots. The slots should be about six or eight inches apart. Each is about six inches by an inch. If you have a 1" hole saw, that makes it easy to cut each end of the slots, then jig-saw in between.

Just behind the inside of the finger slots, cut approx. 1" diameter thumb holes. Leave about an inch of ply between the finger slots and the thumb holes. Your hole saw can make these thumb holes too.

Round off all the corners, and sand all the edges, especially the finger slots and thumb holes. You can stick a piece of slit hose tube or even PVC over the finger slot's rear edge for more hand comfort. That's it, you have a basic one-piece dive plane or SEALplane as I call my version, to separate my simple and easy to make version from complicated and expensive multi-part commercial dive planes, such as the Subwing.

Travis McGee · 26-09-2015, 07:41

The basic operating principle is like a balanced rudder, but horizontal. Your tow line pulls from about 5% forward of the center line. Your fingers pull the other way from about 5% of the way behind the center line. This gives you just enough board balance for easy dives and turns.

I use about 50-70' of 3/8" nylon line. Springy nylon prevents hard shocks when your tow line goes taut. Get your sailboat going about 2.5-4 knots max. 3 to 3.5 knots is perfect. Often we go dive planing on light-air days when we're sailing at about 4 knots and we're ready to turn on the diesel. Instead, we roll up the jib to drop our speed to 3-3.5 knots and spend an hour or two taking turns dive planing.

Just tie off the tow line to your stern, and jump in, facing your boat. When the nylon goes tight, off you go, with no shock on your hands or arms.

The easiest thing to do is surface: just point the board up. Many dive-planers put their index fingers on top of the board to help point the board down. To roll, just cant the board in relation to your shoulders, turning your board and body into a screw. You don't need flippers, just a mask.

In the video Frog Doc is wearing flippers, it was his first try and he hadn't mastered rolling just using the board and his shoulders. Flippers are nice if you drop off the board and have to swim back to your boat, but they make boarding harder. I don't use flippers, just a mask or goggles.

You don't need a snorkel either: just angle the board upward, and you will skim across the top of the water with your head all the way out. With two divers, you can talk to each other while resting on top of the water. You can also hold the board with one hand to clear your ears or wave to your boat.

To be recovered, just go on the surface, signal you have had enough (work out signals in advance, it's hard to communicate verbally at times), and just stay on the surface with the board angled up. It's easy for your crew to pull you back to your trailing ladder. When you are right up to the ladder, let go of the board with one hand and grab the ladder, then let go with the other hand, and your crew on the swim platform will recover the board while you climb back aboard. This is why I don't use flippers, they are a hassle at the boarding ladder under way.

Cormorant · 26-09-2015, 07:44

Awesome! That's my project for today.

I'm interested in the more evolved version in the video, too -- with the side slots and the aft slots with a piece taken out of the trailing edge. Are those for hydrodynamics, or just different places to hold on?

Also, I'm a bit slow on the uptake . . . are Travis McGee and Matt Bracken one and the same?

Thanks very much for sharing this.

Travis McGee · 26-09-2015, 07:46

If you have enough crew on board, here is a trick to make pulling the dive-planer back to the boat very easy. One crew stands on the swim platform pulling the line. Another crew sits on the cockpit or aft deck just behind him, and also pulls the line. With two pulling the line, you can easily pull even a big heavy dive planer back to the boat in no time at all, maybe ten or fifteen seconds. With only one crew pulling, it's harder and takes a little longer, but it's still pretty easy.

Travis McGee · 26-09-2015, 07:50

You can go dive planing in murky water (like this summer from our boat on the Chesapeake.) It still feels great, like a total body deep-tissue massage. But it's about like flying through coffee when you have low visibility.

In the deep ocean it's very cool, and you will see your boat's rudder and keel very clearly from 50-60 feet back. You can dive down at a 45* angle or to any depth your ears can handle. You can swing out 45* to the sides like a water-skier, and perform loops and rolls. If you have two divers out, take care to avoid collisions.

Best of all is warm clear water with a depth of 15-20 feet, when you can skim over the bottom and get the "ground rush" visual effect. You can also cover a lot of area if you are searching for a reef or a wreck this way.

Travis McGee · 26-09-2015, 07:53

Quote:

Originally Posted by Cormorant

Awesome! That's my project for today.

I'm interested in the more evolved version in the video, too -- with the side slots and the aft slots with a piece taken out of the trailing edge. Are those for hydrodynamics, or just different places to hold on?

Also, I'm a bit slow on the uptake . . . are Travis McGee and Matt Bracken one and the same?

Thanks very much for sharing this.

Yes, TM is MB. That's me! The old version with the slots on the trailing edge were tries at various hand holds, but I quit making them. Keep it simple, just use the two slots/thumb holes in the middle. Side and back holds added nothing.

On one board, I cut an access to a trailing hand hold, it was to put the rope into it so the board could be pulled back to the boat without a diver on it. Don't bother. Just recover board (angled up) and diver at the same time.

If the board is in the water with no diver, it will angle down like you can't believe. To pull it back, you will basically need to stop your boat.

jreiter190 · 26-09-2015, 07:54

Trav, great video of you and your crew trolling for sharks. Say hi to Meyer.

Travis McGee · 26-09-2015, 08:02

Quote:

Originally Posted by jreiter190

Trav, great video of you and your crew trolling for sharks. Say hi to Meyer.

If you worry too much about sharks, you'll miss a lot of fun in life.

And in the worst case, it would still be better than dying in an old-folks home full of tubes.