Paravanes: Kiting Underwater

Tethered hydrofoils are underwater kites called paravanes, Neptune's fins. avatars of Proteus, Hellenic sea transformer.

Paravanes are used in shipping (esp. oceanography & minesweeping) & fishing. Just as kite does a copter's job, a paravane is a real submarine.

A paravane tethered to a kite is ultimate sailing. Fin-keel replacement with paravane as mast rig replaced by kite-rig.

The Columbia-Pacific is a evolutionary cradle of the sport-fishing paravane, called "divers", used to take tackle deep without the expense, mass, & complication of downriggers (heavy wire reels) with cannonballs (massive sinkers). A paravane predecessor was the diving plug lure developed for currents & trolling. Side planers are paravanes that pull sideways from a trolling platform or across a current. Otter or side-boards are water kites that spread gear out underwater, like trawling nets.

Dam Killers- Low impact soft waterkites to generate power.

Streamlined stones towed as ballast against floats shaped like surfboards in smooth water & torpedos in chop.

A effective system is finely engineered paravane matched to a big cheap ultralight kite, where the underwater part is small but critical, water some thousand-fold denser, a higher-reynolds domain where tiny flaws kill performance.

a sweeping kite towing a non-sweeping relaunch blimp on a stretchy line attached off the main towline, just as a "kite-keel" might fly underwater attached off a ship towline, itself an "inverse-blimp", mirror elements above & below.

Paravane Trains scale well. Paravane App. upwelling thermal/nutrient loads

The water-sled component, capable of KiteQuiver operations, of a self suffient kite tug is a Kon Tiki, after kite-fishing usage.

Deep clues to kite design hide in plain sight, so the Lower Columbia was a world center of underwater kiting (salmon & tuna trolling), only five miles from the World Kite Museum, & a major international kite festival & no one had particularly noticed these advanced little kites being made by the thousands in many patterns, all along the Lower Columbia River.

''66, NOAA archive- V-fin served as underwater kite to bring sensor (bottom penetration sonar) close to bottom. Deployed off of EXPLORER- "...tests confirmed that the paravane system was reasonably easy to handle..." Sahlin & Österlund

Lynn, et al's MOPHs (mode optimal planing hydrofoils) that work as such until a threshold speed, then rise to the surface and plane. A case for "whale tail" MOPHs on kiteboats lifted upward, albacore forebody dragged up by mighty kite, the tail planing fast as spit, flying-fish jumping rather than humpback-breeching depending on size & conditions.

At left is a a simple rig i used to make tidal power at a bridge where the Chinook River reverses with the tide.

Eager to try paravane/sea-anchor variants for pointing & operations like "walking" down a big kite from a sea-anchor with only a small boat, a fast powerful way to douse. Fishing has gone wild over paravanes, lots of cheap little underwater kites to do all kinds of tricks, the aquatic side of a toy HOPA could be cobbled from tackle-shop COTS.

Non-violent fishing with paravanes, seacams, etc., feed the fish & take a pix.

Paravane summary- tethered hydrofoils are cheap & powerful tools that generally work as expected at low speeds (<4 kts). Long boards are resistent to yaw inputs, compared to high aspect wingtip inputs. pilot paravanes didn't work as well as desired. A surface planer/payload component evolved

2007 Paravane Collection

above- the intial collection of paravanes, a dozen or so are sport fishing divers & sideplaners, the rest are my experiments

paravane 1

medium floating side planer carved in wood with variable flap

bird paravane w/ NW Pacific native style graphics flys in Black Lake, Jan 08

paravane 2

prototype shunting side-planer, OJ-foil (pierced-Jfoil)

paravane 3

small sinking diver by Frank Unford of Ilwaco, with depowering bridle slide, angular delta wing, heavily ballasted.

paravane 4

floating diver, Triple Threat by Pescaro of Astoria, surfboard shaped, sliding lead ballast, sliding bridle point

paravane 5

medium floating diver, Diving Board K-Type by Yo-Zuri, boat shaped, lead-free, fat bouyant tail, sharp nose

paravane 6

small floating diver, Jet Diver by Luhr-Jensen of Hood River, lead free, bouyant chamber aft, delta wing, flat LE

paravane 7

small sinking diver, Deep Six by Luhr-Jensen, shovel shaped, flat LE

paravane 8

small floating diver cut from polythene sheet

paravane 9

updated Pink Lady by Luhr-Jensen, this is said to be the original sport fishing diver from around 1968

paravane 10

small sinking diver, Fish Seeker by Doelcher, with flush lead ballast, rounded chined scooped delta wing, & highly variable bridle/tail adjustment

paravane 11

side-planer, Hot Shot by Luhr-Jensen

paravane 12

prototype shunting side-planer, J-foil from a sardine-can lid

paravane 13

a donated commercial fishing stabilizer, sweet...

Below: How some trawlers carry their paravanes on the outriggers.

Lately i like mere edging in water, like the kite-surfers, its very low drag if water-loading stays low, it makes a ridge of water to leeward & a stable cavitation upper windward surface.

To avoid seaway buffet hang only humans & light luggage in air under sky kite, while keeping massive cargo on the edge-board hull, in calm just use dangling stabilizers like fishing boats.

Notes-

Stock paravanes are modified by drilling accessory holes or welding to mount features.

Small = <6 in., Med = 6-12 in., Large > 12, the bottom large range suitable for smallest kayaks, inflatables, canoes.

Paravane Accessories

Parvanes are made to side-plane (tack sideways from straight down) by laterally shifted flotation &/or ballast. Drogue turbines & even smaller "pilot" paravanes attached to the paravanes to modify swim. The Dipsey-Diver shifts ballast. These trim inputs do destabilize somewhat, so moderation is required.

Streamline float-tails of cork or polysytrene foam kept paravanes from sinking too far. Lead is avoidable, but if used is preferrably salvaged & recycled. Stone weights are greener & cheaper than lead.

Tails of many kinds were made. Most floated. Some had spinner drogues. Some were beaded &/or knotted.

quality leaders of dyneema or steel reduce underwater drag considerably.

Luhr-Jensen Trolling Rudders under utility study, Sky kite equivalent pondered..

Paravane/HOPA Operations

Launch- point down wind, launch paravane forward & windward, launch kite leeward of paravane, begin tow between paravane & kite.

Dowse- drop sea anchor off kiteline end, "walk" boat down line to kite.

Tacking- set paravane on starboard or port tack, allow kite to follow tack, it will tilt into the apparent wind stablely. A tacked kite is crash-prone.

Beating- suspend "jib" kite under non-tacking lifter, trim by hauling in bridle.

these days i have a collection of tethered hydrofoils to play with as HAPAs off an inflatable kite-boat. a survival suit helps the seasonal challenge. The water kite flys against the sky kite & the boat is towed between them. one need only trim the paravane & the kite leans itself to the correct side.

hoping the kite tech field will float all of us in the new year,

comment to: santos137@yahoo.com