Youngblood .21 mono setup help

[tnrcboatracer]

The cross wise rocker is less of a concern than the longitudinal. Across the hull rocker makes a compound Vee angle. This is not that unusual. Most huls do not have the longitudinal rocker. The Seaducer is the exception, they have the rocker by design, but also do not run tabs. My 44" 1.01 powered 'ducer runs a confirmed 67 mph all day without tabs. I need to get it out with other boats to confirm the setup, it might be a little loose right now for heat racing. I just rebuilt the drive line and am not 100% sure of the strut angle. Ironically, a loose setup causes the Seaducer to Seadunk....LOL

Speaking of drive angle, what about the strut alignment on the Youngblood? Did you check that?

I respectfully disagree with Mr. King. I have kept straight bottom hulls on the water: it takes the proper combination of tab and drive line angle to balance the hull at speed. I tended to have move of an issue with torque roll on the larger hulls. It was not uncommon to tip the edge of the RH tab down to counter torque roll. BUt not so much on the 21 hulls, as they don't have as much prop area. I used to do it with split tabs on my Team Shadow hulls. Yours may be a little extreme, I would expect it to be 1/32-1/1/16 " max. The outboard corner of the tab should be out of the water most of the time on the straights. Did you run the straight edge across the tabs? The tab should be about 1/32" above the bottom surface of the hull. It also doesn' hurt to fair the tab into the transom with some spot putty. The most important thing is to have a smooth bottom. See John Finch's comment about trimming a mono with a drop of CA glue on the rear edge of the hull. It doesn't take much.

 

[RodneyPierce]

John, got everything back together, straightened out the trim tab, set them 1/32 above the hulls bottom plane, and adjusted the strut to neutral roughly 5/32 above the bottom of the hull. It is offset a slight amount.

I also noticed that the tabs are not parallel with the bottom surface of the hull. They are tipped upwards a small amount towards the rear.

 

[moparbarn]

rodney, i have a .21 mono made by ed knudsen down in fla. it did exactly what you're describing in the straights. faster it went, the "flightyer" it got. literally would jump out of the water. tried ALL sorts of stuff, no luck. john finch & steve speas took a look at it, & the ONLY thing i did was make sure the transom to bottom edge was ABSOLUTELY square & sharp. was a totally different hull, stable & fast. they likened the SLIGHT roll in the edge to an airplane's elevators, it's always up, & the boat tries to roll back on it, since the water climbs it instead of shearing off cleanly. trim tabs adj., strut adj., props or cg did no good. just a little bondo & sandpaper made it a whole new boat. looking at your pics, i see about as much roll to that area as mine had.

 

[tnrcboatracer]

Robin, do you have a pic of that mono. I bought some mold from Ed back in 88-89 and there were 2 different styles of 20 mono hulls in the lot. I was wondering which one had the issue you describe.

Also, I tried to call you from your message on the Dock, but the number I have in my phone is the old one.

 

[RodneyPierce]

rodney, i have a .21 mono made by ed knudsen down in fla. it did exactly what you're describing in the straights. faster it went, the "flightyer" it got. literally would jump out of the water. tried ALL sorts of stuff, no luck. john finch & steve speas took a look at it, & the ONLY thing i did was make sure the transom to bottom edge was ABSOLUTELY square & sharp. was a totally different hull, stable & fast. they likened the SLIGHT roll in the edge to an airplane's elevators, it's always up, & the boat tries to roll back on it, since the water climbs it instead of shearing off cleanly. trim tabs adj., strut adj., props or cg did no good. just a little bondo & sandpaper made it a whole new boat. looking at your pics, i see about as much roll to that area as mine had.

Awesome, this might fix the issue then! We will know on Sunday!