# from riblets to swordfish oil.



## Chas H (Sep 6, 2013)

Black Marlin can swim at speeds up to 80 mph. Speed has been measured by how fast they strip line from a fishing reel. Swordfish are slower, but still fast.

Apparently swordfish secrete oil from the base of their beaks. The oil allows them to swim 20% faster than without it. I don't how that was calculated.

I want swordfish oil on my boat bottom the next time I go racing.
-CH


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## overbored (Oct 8, 2010)

simple just tie your pet swordfish to the bow during races


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## gamayun (Aug 20, 2009)

Secreting oil would be difficult to get past water quality regs  but I've often thought. some kind of bubble-making device might do it. It looks like foils might be the ticket though.


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## RichH (Jul 10, 2000)

gamayun said:


> Secreting oil would be difficult to get past water quality regs  but I've often thought. some kind of bubble-making device might do it. It looks like foils might be the ticket though.


Just about any compound that will reduce the surface tension of the water will do.
Unfortunately emitting oils, surfactants, soaps, etc. etc. in the water etc. is illegal, well long before 'the EPA' under 'the racing rules'.

Air bubbles are good; but, nothing can be 'pumped' and the only way to do that is to have a flat-ish or 'tunnel-hulled' skimming dish planing design which traps air bubbles (quite like a ram-jet) under the hull .... when youre well over ~15kts of boat speed.
If you really want to reduce surface tension, reduce the surface by getting your foils to lift the boat 'out' of the water. 
;-)


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## hellosailor (Apr 11, 2006)

Mysterious oils (slime and goo) and air injection are all old news, and all were long banned by pretty much any sanctioned racing. So if you really want it, you'll have to start a new racing organization or expect to be DSQ'd.

Same thing for microtexturing on the hull.

Viking longboats apparently suck in air and naturally create air injection under the hull. This was stumbled upon when one of the recreations was put to sail, and it made higher speeds than anyone thought it should be making.

FWIW.


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## RichH (Jul 10, 2000)

hellosailor said:


> Viking longboats apparently suck in air and naturally create air injection under the hull. This was stumbled upon when one of the recreations was put to sail, and it made higher speeds than anyone thought it should be making.


If I remember correctly, that boat was named _Gaia_ and was a Norwegian Knaar replica - a viking long distance merchant replica vessel, and not an open deck 'longboat' (raider). The design was pre-medieval from about the years 900-1000.

We 'tried' to sail near and 'keep up' with her on the Ches. on or about 1991 during her visit to N. America. She had up just simple square-sail on a beam reach. We were on a PHRF-65 rated sailboat ... we couldnt keep up. 
That Knarr was 'incredibly' fast, in spite of its comparatively small sq.sail.

Gaia,a replica of a Viking ship ? Hvalfangstmuseet

;-)


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## paulk (Jun 2, 2000)

Woodenboat had a story a while back about a Viking longboat returning from Ireland to Denmark hitting 13 knots with no problem. They're long, narrow, and very light,even without the "bubble effect" of the lapstrakes. On a beam reach they could probably really take off. I wonder what the SA/Disp ratio would be compared to our leadmines.


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## RichH (Jul 10, 2000)

The exposed edges of the strakes are probably acting similar to 'lifting spray rails' mounted near the bow waterline on some powerboats. 
The lifting spray rails help to lift the bow for an 'earlier' episode of planing than without them. The boat begins to plane much earlier and with greater efficiency.

https://patents.google.com/patent/US5205235A/en


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