What about this???

BillPutney · #1 10-13-2008, 09:07 PM

Post deleted by capt_chuck

BillPutney · #2 10-13-2008, 09:08 PM

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BillPutney · #3 10-13-2008, 09:10 PM

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BillPutney · #4 10-13-2008, 09:11 PM

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BillPutney · #5 10-13-2008, 09:13 PM

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BillPutney · #6 10-13-2008, 09:15 PM

finally I got it . I hope these will help with the diagnosis

Caymanboy · #7 10-15-2008, 07:55 AM

In my opinion, the 'wedges' that are on the bottom are the right idea but are the wrong size and in are in the wrong place. They should be a little thinnier and aft further, i would recommend a clamshell installed covering 1/2 the hole, creating a venturie that sucks the water out, right now with them being so far forward it is pushing the water in, the boat is not going fast enough to suck it how, too much bottom hull pressure.

BillPutney · #8 10-15-2008, 08:17 AM

I checked the port side drain and it looks original. There is no extra wedge stuck on and puttied/marine-texed over as you saw in the pic.Although there is some putty around the drain tube on the starboard side . I think someone along the line replaced the tubes and puttied them in. The port side is smooth and in line with the hull,no addtional ramp.In the pic you can see that there is a slight gap between the front edge and the hull, when it gets light this morning I,m going to try to pry it off.

Capt Chuck · #9 10-13-2008, 10:42 PM

WWP2
I hate to say it but I have never seen such a self bail mess in my life. That setup is a after market screw up and given the right conditions can cause you to sink

Bottom Line, It appears the bottom has been ground down till you now have a hook in the hull. You need to fill those holes up, take off the faring block, re-glass & true the bottom and run some decent floor drains out the transom as I previous suggested.

Some others (Don Herman) need to chine in here.

Bushwacker · #10 10-14-2008, 12:11 AM

You're right Chuck - SeaCraft never built them like that!

Just noticed that axial "step" at the chine! The idea of an axial step is to create a flow separation and trap air much like the lateral steps on the VDH. I have a book by a famous British guy named Uffa Fox, who built some racing hulls with a series of axial steps and wedges in the 1920's. The hulls had about 3 equally spaced steps along the bottom, giving them a "saw tooth" appearance when viewed from the side. The concept was that when a wave forced the forward section of the hull out of the water, the increasing "angle of attack" on the rear section of the hull would create extra lift and force the bow back down, much like a trim tab. I believe the concept worked fairly well and created a very flat running angle.

The problem with this one is that they didn't do it right! You need a sharp 90 degree step in the surface to cause flow separation, not 45 degrees like this one. I suspect the water won't separate, but will just follow the surface and blow right up thru the scupper, especially at low speed! Looks like someone tried to add a wedge to the aft end of the outer panel as well (the hook that Chuck mentions) because the lateral step is gone in that area. That feature will also increase the pressure in the area forward of the wedge, further aggravating the problem of blowing water up thru the scupper! The other small wedge just forward of the scupper is also not original - hard to tell w/o a scale in the photo, but it looks MUCH thicker than the one Potter used on the 20's, which were less than a 1/4" thick.

If you carefully sight down the chine of a 20' hull from forward looking aft, you can see where Moesly DID build in a slight wedge or hook in the outer panel but it's very subtle - the chine drops down maybe a 1/2 inch over the aft 8-10' of the hull. This panel is almost clear of the water at about 40 mph, so this wedge would have no effect at high speed; I suspect it's purpose is to improve with low speed planing and load carrying ability. It may be there on the 19 also. Haven't looked at the 21 or 23.

Bottom line is, Chuck is right, the only way to fix that thing is to rebuild that section of the hull to original configuration which is well proven! I'd also move the scuppers to the transom and maybe cross them also, the way Moesly used to do it.