A concave skiff bottom issue/interesting problem

[wallacethegreenmonster]

So i have built a 16 foot flat bottom plywood skiff a year ago and have an interesting problem. I must not have flared the sides out quite enough because the bow of the boat points down slightly and when upside down the boat essentially has a concave appearance or the opposite of "rocker". I am still able to move along pretty well with a 30hp 2 stroke on the back but i am a little afraid of going full power because of an occasional bow digging into to the water at high speed. Also the boat seems to be better at higher speed if I am going into the wind, or if I have the motor trim pin in the furthest out position. Is there any way to add some sort of wedge to the bow underside or should I just keep more weight in the back of the boat? Thanks. WGM

[SaltyD from BC]

The first thing that comes to mind is installing a stiff straight keel and see if get the hook out. A hook on the forward sections doesn't sound like a good thing.

[esingleman]

How much lower would you say the bow is compared to what it should have been? Or how deep is the concavity compared to the original design shape?

[JimD]

Got a pic for us, Mr Monster?

[Thorne]

Sounds really dangerous to me for an outboard powered boat with that size engine!

Sure be tempted to rebuild the front 1/4 of the boat by cutting out the fore part of the bottom and building one that curves up a bit at the bow.

[Thorne]

Here's a photo of the boat in question, showing the hook at the bow.
http://i214.photobucket.com/albums/cc153/wallacethegreenmonster/Picture308.jpg

I **guess** you could glue up several layers of heavy ply and add that to the front part of the bottom, tapering it from thick aft to thin forward to create a tiny rocker at the bow. You may have to grind off some of that fiberglass down there, but may be able to just glue and screw it into place, then glass over it to match the rest of the bottom.

[boylesboats]

Okay I am building a 14 footer of my own design... Lots of rocker..
It not for speed, mainly for rowing and small 5 horsepowers outboard..
In every design I did.. I add a little covex to chine, about 1/2"... and plus add keel inside...
Here photo of 14 foot skiff in the background

http://i128.photobucket.com/albums/p182/boylesboats/A0003.jpg

[G. Schollmeier]

This is a common problem with first time small boat and canoe builders. I suspect that you have a center seat or thwart. You should check to see if the beam is correct. If not, this will cause the problem you described. If you can remove the thwart and pull the gunnels to the correct beam you will find this causes the bow to move.

[esingleman]

I'd remove the stem, cut a wedge out of the side planks down in front and reattach the bottom and trim. I'd start with a little wedge and keep going until it looked pleasing to the eye.
I don't think you'll get in too much trouble if the bow were a little higher as long as it looked okay. Then be careful how much HP you apply into waves or chop, after all it is a flat bottom boat.