Glen-L.com

It is great to hear that you got value from the content on the site. I don't think I ever publicly thanked Mr Hot Rod for hosting that site for me, and for the many hours he spent assisting with loading and organizing the content... Thanks, Paul!

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Bruce.

~~ Do what you love, and love what you do. ~~
~~ To me - only my boat is not yet perfect. Everybody else's is to be admired for I know the path they have walked (Dave Lott, 2010) ~~
Dow's Monaco Project

have a look at 5.16 :

http://www.youtube.com/watch?v=uaw6NZFguTQ

Nice sound!

What a great picture of your boat. It looks like a lot of folks in your area build their own boats.

At what speed did you experience your porpoising?

dave

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Dave

My Riviera build - the Midnight Cry Project

Video of Midnight in Action
Blog

Few things in the world measure up to the thrill and satisfaction of boating in a boat that you built.

about 35 knots on that video.

Ok, you might want to contact Bruce Dow and discuss with him the solution he came up with. You have a lot more top end you can experience if you get rid of the bounce.

dave

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Dave

My Riviera build - the Midnight Cry Project

Video of Midnight in Action
Blog

Few things in the world measure up to the thrill and satisfaction of boating in a boat that you built.

I just had about 3400 RPM at that speed so the boat is faster than that. But the river is not that wide and i had no beer, so i did'nt floor it

But kan someone tell me more about Bruce idea?

Best regards

Mattias

Looks and sounds great, Not sure if this is any help to you with the porpoising but if someone can work it out it might be
http://illustrations.marin.ntnu.no/hydr ... index.html

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Malahini, SEAN-NÓS http://www.youtube.com/watch?v=Qd6vkPjEy4U
http://www.youtube.com/watch?v=8uDVzcVpdhc
crackerbox build http://s753.photobucket.com/albums/xx17 ... =slideshow

Hot Rod - Why did you not come up with that chart. Slacking off on us?????


Regarding the porpoising. My studies suggest the boat pushes a small wall of water ahead of itself. As the boat goes fast it climbs up the wall causing the bow to drop. The bow drops and bounces off the water allowing the next wall of water to form under the bottom. The faster you go the larger the oscillations. The remedy is to reduce the angle the boat moves over the water so that the wall of water is not being pushed up.

With an inboard, the process to lower to bow and thus lesson the angle of attack can be achieved in two ways:
a. The rake of the prop can be changed to a more forward rake. This causes the bow to drop. Bruce Dow had good sucess with this
b. A small ( I mean small) trim tab can be fastened to the bottom of the boat at the transom forcing the bow down. This is what I did. My tab is a wedge is only 5 inches long, 3 inches wide and at the thickest edge only 1/8" thick. I have one on both sides of the prop even with the transom trailing edge and under the motor stringers.
c. Well there is a 3rd - mount hydraulic trim tabs on the transom. I prefer to leave that to the speedsters such as Hot Rod and V-driver.

Good luck. Porpoising is common with us newbies that want to power up hulls designed 50 years ago with smaller engines. So you are not alone in this area.

dave

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Dave

My Riviera build - the Midnight Cry Project

Video of Midnight in Action
Blog

Few things in the world measure up to the thrill and satisfaction of boating in a boat that you built.

Gorgeous!! Congrats

Btw... is that teak on the deck?

Now that's just sweeeeet

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Hey! I built a boat ! No Really, I did !
http://davesboat.blogspot.com/