Dumas Sport 20 Pay'N Pak Build
#26
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RE: Dumas Sport 20 Pay'N Pak Build
Okay everyone, time for one of my few changes. Here are two pictures showing a redone bottom profile and the difference in height between the designed height and redone height.
#27
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RE: Dumas Sport 20 Pay'N Pak Build
Yesterday was a slow day on the build. The cut lines needed to reprofile the bottom were laid out yesterday so today I'll be cutting off the excess material and cutting out lightening holes in all the frames. I should be able to post pictures tonight or tomorrow for you all to see the difference.
#28
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RE: Dumas Sport 20 Pay'N Pak Build
HJ,
I'm not familiar enough with this kit to know what the designed framing looks like (I don't have a kit) so my questions may be kind of weird.
What is the purpose of raising(?) the bottom? Are you moving the "break point" of the bottom aft? Or making the tunnel deeper?
Do you think you could show the elevation (side view) from the Dumas drawings with the changes you're making?
Thanks,
Ken
I'm not familiar enough with this kit to know what the designed framing looks like (I don't have a kit) so my questions may be kind of weird.
What is the purpose of raising(?) the bottom? Are you moving the "break point" of the bottom aft? Or making the tunnel deeper?
Do you think you could show the elevation (side view) from the Dumas drawings with the changes you're making?
Thanks,
Ken
#29
Thread Starter
RE: Dumas Sport 20 Pay'N Pak Build
You're ahead of me on that one Ken. My plan is to take one of the sponson insides and place the reworked cross frames into the slots cut at the factory. For a comparison, I'll have marked the original bottom in some way, probably masking tape to show how it's been changed.
As for the why, this comes down to when the kit was designed. Dumas designed this kit approximately 30 years ago when engines weren't as powerful and the hull designs were very crude as compared to now. To compensate for this, the bottom was angled up very sharply from the back of the sponsons to the front of the center section. With the new engines generating so much power, that sharply angled up front section now is a liability as it can lift the front too much and cause the boat to blow over. What many people have done, me included, is move the break in the bottom, were the two bottom panels meet, from the back of the sponsons to frame 6 in the middle of the stock radio box. This causes the rear of the boat to be supported more by air pressure and moves the pressure point further aft, greatly reducing the chance of the dreaded blow over
As for the why, this comes down to when the kit was designed. Dumas designed this kit approximately 30 years ago when engines weren't as powerful and the hull designs were very crude as compared to now. To compensate for this, the bottom was angled up very sharply from the back of the sponsons to the front of the center section. With the new engines generating so much power, that sharply angled up front section now is a liability as it can lift the front too much and cause the boat to blow over. What many people have done, me included, is move the break in the bottom, were the two bottom panels meet, from the back of the sponsons to frame 6 in the middle of the stock radio box. This causes the rear of the boat to be supported more by air pressure and moves the pressure point further aft, greatly reducing the chance of the dreaded blow over
#31
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RE: Dumas Sport 20 Pay'N Pak Build
Okay, here is the approximate difference between the stock bottom profile at the top edge of the lower tape and the new profile, shown at the bottom of the upper tape line. At the sponson transom, the difference is 3/4 inch, so it's quite substantial
#32
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RE: Dumas Sport 20 Pay'N Pak Build
And slightly more was accomplished tonight with the filling and sealing of the porus side of the cross frames with mixed microballoons and epoxy to keep the weight down as much as possible. For those that are familiar with Dumas kits, you know what I'm talking about
To keep the glueing areas clear of microballoons, I taped off all the areas that epoxy will be used later before spreading the filler mix.
To keep the glueing areas clear of microballoons, I taped off all the areas that epoxy will be used later before spreading the filler mix.
#33
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RE: Dumas Sport 20 Pay'N Pak Build
After 24 hours of cure time, the tape and clamps (in the case of the transom) have come off. I placed the transom on a scale and found it to weigh in at .55 ounces, a full .5 less than the 5 ply 3/16 inch transom used on my full race hulls. At this point, I'm not sure if that is a good thing or not. The sponson insides and engine bay walls will get the same treatment tomorrow so it's getting close to the start of assembly. Pictures will be posted after I finish sanding the parts down and get all the lightening holes cut
#36
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RE: Dumas Sport 20 Pay'N Pak Build
ORIGINAL: Hydro Junkie
You and me both. I''m hoping the boat is a good runner since the wife has claimed it already
You and me both. I''m hoping the boat is a good runner since the wife has claimed it already
#37
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RE: Dumas Sport 20 Pay'N Pak Build
Her building ain't going to happen. The wife and tools are like oil and water, they don't mix. What is funny though is she's already picked out a color, IT HAS TO BE PURPLE!!!!!!!!!!!!!!!!!!!!!!!!!
#41
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RE: Dumas Sport 20 Pay'N Pak Build
She's not color blind so that won't work. My problem is I have to get her to find a color she wants and then figure out the graphics package that she wants, not an easy task as she will want to see the paint on the boat before figuring out what she wants on it[:@]
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RE: Dumas Sport 20 Pay'N Pak Build
Have somebody draw one out and color it to see what it would look like. I could be a nice guy and draw one up for you without any colors on it? Then you can copie it,then you can color it in and draw graphics in it. Its best thing to do is make 5or 6 copies of it.
#43
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RE: Dumas Sport 20 Pay'N Pak Build
ORIGINAL: Hydro Junkie
She's not color blind so that won't work. My problem is I have to get her to find a color she wants and then figure out the graphics package that she wants, not an easy task as she will want to see the paint on the boat before figuring out what she wants on it[:@]
She's not color blind so that won't work. My problem is I have to get her to find a color she wants and then figure out the graphics package that she wants, not an easy task as she will want to see the paint on the boat before figuring out what she wants on it[:@]
#45
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RE: Dumas Sport 20 Pay'N Pak Build
ORIGINAL: Blackout
#47
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RE: Dumas Sport 20 Pay'N Pak Build
Darker!
ORIGINAL: R.J. West
Here's a nice shade of purple that wouldn't look too much out of place on a boat......... that hasnt been built yet
Here's a nice shade of purple that wouldn't look too much out of place on a boat......... that hasnt been built yet
#49
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RE: Dumas Sport 20 Pay'N Pak Build
I honestly think thats a great shade of purple. Add some white stripes and maybe some numbers, clear coat over it, it would look sharp.... maybe throw in some metal flake while we're at it.
But the thing is..... You gotta build it first!
But the thing is..... You gotta build it first!
#50
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RE: Dumas Sport 20 Pay'N Pak Build
Darker for trim color, lighter with silver metalic for the deck and cowl accent color. Can't go to wild or she won't want it. BTW RJ, if I have my way, she will be bringing it along on our road trip this summer so she will have a boat to run as well.