Myth busters
- Thread starter DianaOfBurlington
- Start date
Hate to tell you this but number 5 isn't a myth! its an actual formula that applies to displacement boats! and is the best close predictor for the the maximum speed of a displacment boat. This formula does not apply to boats ( including sailboats) that are capable of planing.
Better ... the chart (plotters) says that there's a couple of feet of water under our keel, so how did we touch that rock?
I was surprised to see people disputing the notion of "hull speed." Unless they are referring to situations where the hull comes out of the water such as surfing waves downwind. Would love to hear more on this.
And it's based on the wave length generated by a certain length hull.. Longer waves travel faster. That's the reason the old CCA boats had the long over hangs. that rule measured waterline, so when the boat heeled, the water line increased, thus higher theoretical hull speed. I said theoretical be cause it still is not absolute. Long skinny hulls CAN move faster than short tubby hulls with the same waterline
was98strat you need to surf once or twice... a non-planing boat will surf past it's "theoretical hull speed" which is all that formula is good for.
Also the waterline of a boat "usually" increases with heel. Nullifying that theoretical number. "Hull speed" of my Capri 25 was 5.9 knots... HOW did I do this... and before you say my knotmeter was off, I confirmed these numbers with GPS... no current, flat lake.
But I have some other myths...
"Reef before you think you need it."
"When winds are up a reef and a smaller headsail are faster"
"Red sky in morning sailors take warning"
"Red Right Returning."
"Sailing flatter is faster" - reference to keeping a boat with little heel to get best VMG... I'd argue sometimes 25-30 degree of heel is faster, depending on the boat.
Also the waterline of a boat "usually" increases with heel. Nullifying that theoretical number. "Hull speed" of my Capri 25 was 5.9 knots... HOW did I do this... and before you say my knotmeter was off, I confirmed these numbers with GPS... no current, flat lake.
But I have some other myths...
"Reef before you think you need it."
"When winds are up a reef and a smaller headsail are faster"
"Red sky in morning sailors take warning"
"Red Right Returning."
"Sailing flatter is faster" - reference to keeping a boat with little heel to get best VMG... I'd argue sometimes 25-30 degree of heel is faster, depending on the boat.
