Glide in real world hull speed

-- Last Updated: Jun-16-16 8:13 PM EST --

Have read a couple a post recently here about kayak speed. Have not come across what some call GLIDE in the post. Not wanting to hijack other threads have decide to start my own and ask why is this not a consideration.

What is glide? It is how well the hull keeps moving between strokes. At a lower strokes per minute this is important.

Way back in my younger days a Jensen racing canoe was fast but now in my older days a DY designed Wildfire has the same speed with me as a motor. A Mohawk 14 solo is about 30% slower than the other two. At about the same cadence the Wildfire stays in motion longer than both the Jensen racing canoe and the Mohawk solo 14. If I could generate the strokes per minute to keep the Jensen racing canoe up on the plane or wave then it would be the fastest.

For most of us the wetted area and glide comes in
to play more than what the maximum hull speed we do not have the bodies to maintain.

How do you use math to describe glide and
how to look at a hull shape for it?

sorry to burst your bubble

– Last Updated: Jun-16-16 8:11 PM EST –

The Jensen is faster ( 1.55x waterline length) The Wildfire being shorter has less skin.

What has happened is you changed. Paddling is a partnrship between craft and you. You got older and generate less horsepower. You no longer can overcome the skin friction of the Jensen as well

Be glad you can paddle
Glide is a function of hull smoothness too. The more wrinkled you or your boat are the slower you go.

A quibble on terminology

– Last Updated: Jun-16-16 8:19 PM EST –

I don't think you are talking about glide and hull speed. When at hull speed, your boat will slow down quite a lot within an instant of when you cut the power. There's just too much resistance when you are going that fast. The faster you go, the more pronounced the deceleration will be between strokes (that's the main reason racers use a very high stroke rate). It's at much slower speeds where you can really make use of glide. In fact, if you ever decide to just glide as far as you can, you'll see that the majority of the distance is covered at a snail's pace because the slower you go, the less you decelerate (because resistance decreases too).

of mouth

You could probably fit a function of
Glide being proportional to the inverse of cross sectional area at or below the water line plus a less important factor of the inverse of total wetted surface area.

In other words look for a narrow profile that floats enough to keep the minimum wetted surface area and long enough to have reasonable hull speed.

Paddling stand up paddle boards is a great way to get a feel for hull shape design and what gives you maximun glide for physical output.

list ? top ten
non racing gliders ?–635

thru or over
A quote from your link about power boats:

“When a vessel’s bow drives into a head sea it can do two things: go through the wave or over it. Flared bows are designed to go over the wave, but in order to do so, they need additional engine power to first drive the yacht up the face of the wave and then over it. Wave piercing bows tend to go through the wave and usually have the main deck located high enough that the crest of the wave will not climb upwards onto the deck.”

I think there is an analogy to sea kayaks in head seas. My Solstice GTS went up and over, but my plumb bow QCC 700 goes through, or at least does not rise up as much. I think the QCC is much more efficient in head seas when one is going much slower than hull speed.

This has nothing to do with the glide question of the OP.


– Last Updated: Jun-18-16 7:04 PM EST –

flares going over but always in the water...there's a rise up then thru the crest. We've submerged in troughs then popped out...the flare could be a component of the buoyant pop out design.

The QCC and the powered motor hull would be more under control of the sea when 'piercing' but gliding over in touch the the water as before..or after...the hull is poised for your next move.

Not gliding but I wanted to throw out a base line.

Sure, glide would be less wet area, longer in the act of reducing eddy drag from fishbelly to stern, less deflection from side forces, less less....

Idea Glide occurs in a zone less than hull speed suggests eddy drag from fishbelly back to stern is a primary factor producing Glide....? in the 3/5th's area ?

Are there interviews or writings from/with Jensen or fellow designers ?

downside up

the Russian Gazpout Lemans car