Godzilla and hard chines

Well not quite kayak but I do cover a lot of water under human power. I have a very good idea of what is sustainable by various humans. See attached.

Rick W

 

Interesting. I can't get the spread sheet to download though.

Still, the difference is those racing and those out just to be paddling. The people I am aiming this design at are in the 3.5-4 mph speed 90% of the time. These are people that take their boats out once or twice a month. Not athletes nor any desire to paddle fast for any length of time.

So that is why I used that speed. Maybe that is a mistake in Michlet? My thinking was optimize it at the speed it would be used at most of the time.

I ran one more model that looked pretty promising. I love the shape, similar to what I started with.



I ran it through FreeShips Kaper numbers and put it a spreed sheet with my existing design. I was surprised at the results. No difference in what I started with. The lines are almost on top of each other.

I put in the one where I let Michlet just run and it's a dramatic improvement, but I am not sure my target group would be comfortable in boat with that low stability. But it has peaked my interests.

I have one in the shop almost done with a little higher stability. Once I paddle it I will have a better feel for exactly what the numbers mean when your sitting in the boat.





Even if I have not improved my design I have sure learned a lot about Michlet and will continue to work with it and learn to use it better.

 

The bottom of your drag curve shows 3mph = 3.45kts.

3mph is 2.6kts. Not very fast and somewhat slower than 3.45kts.

Most untrained paddlers I see have little difficulty holding 8kph or 5mph for an hour or two unless they are on a 2m long sit-on. Then 6kph is about their limit.

The shape your are seeing is typical of the shape for a hull that is operating below the hull speed. As you approach hull speed or exceed it the ends tend to get fuller.

Rick W

 

I had to look that conversion up, must have multiplied when I should have divided. I created this chart for someone else and then recycled it. Thanks for pointing that out, I would have never noticed.

You must grow them stronger and leaner down under! I know a few paddlers that paddle at those speeds. Most are competitive people and do some racing. But the group I am aiming at couldn't or maybe wouldn't paddle at 5 mph for an hours time.

 

There are a few in the Over 50s group that I know can sustain 7kts on a surf ski. The younger guys are up around 8kts in an endurance event in calm conditions. These guys are fit but not quite world class.

The 70 plus grandmothers I have seen paddling will amble along quite happily at 8kph for hours. I guess a 70 yo woman paddling a kayak is not all that common though so they might be quite special.

According to the attached chart I am at the bottom end of untrained male at full-time rate. I am not overweight. In my defence I am on the mature side of 55yo. (The chart is from the xls file you could not open) At the 5 minute level I can match the bottom of the moderate. Peak power is back at the bottom of the untrained.

Rick W