23 CC rebuild - shine

[3rdday]

Joel will be able to answer best his intent, he's one very, very, intelligent dude.

I am going to guess that the effect will be quicker response and a more dramatic response.
The trim tabs may also be in cleaner water being inboard, where the bow and midship will spread and knock down minor chop.
Also; remember the outer panels are the low speed panels. Locating inboard may help reduce parasitic drag at higher speeds, by raising more of the hull out of the water that much more, hes reducing wetted surface area.

[Bushwacker]

I would think the outer panel would be the preferred location for the trim tabs, particularly if you're using them for lateral (side-to-side) trim control, which is mostly what I use mine for. The outboard location would provide a larger rolling moment for the same force/tab deflection, or conversely, would require less tab deflection (and drag) for a given rolling moment.

Deep V hulls also generate more lift and rise higher out of the water as speed increases. The 1973 Boating magazine test of the 23' Tsunami/Sceptre contains a shot of the hull with the chine completely out of the water at the transom at high speed (over 40 mph). (I can send a .pdf file of that article to anyone who wants it if you'll PM me with an e-mail address.) This means that trim tabs on the outer panel would tend to be mostly out of the water at high speed, reducing drag at a condition where you typically don't need the tabs anyway.

Of course if you're running fast enough that you need tabs to prevent chine walking, that's a whole other issue! Might need to big long tabs like race boats use for that situation. There is also probably a little more aeration in the water at the outer panel at higher speeds which would tend to reduce the lift generated, but the tabs on my boat seem to be very sensitive and effective for lateral trim control at normal 20-30 mph cruising speeds.

[shine]

just not enough room. Compromise was to have bracket lower for free diving. I looked into the "blade" type tabs, but they required through bolts in area that I have already foam filled. So yes, I will not have as much lateral trim control as I would if there were on the outside panels. I did see another builder here who notched the bracket to allow the actuators to fit on the outside panel, and I think that's a good solution if you really want them on the outside. I don't really see it being a big deal on this boat.

Normally I could have just slid them as far over as they could go, but due to the changing hull panels on a seacraft, you have to have the tab on one hull panel or the other. A more traditional V bottom would have allowed more room for a wider/shallower (like a 18x9) tab.

[csurf]

Looking really good.. Where did you get the trim?

[McGillicuddy]

Thanks, shine. I concur it'll be fine. It doesn't take much trim to alter the running angle, regardless of tab placement. I just removed 16" tabs from the center panels of the 21 because it appeared that when trimming bow down they were stirring a lot of water around and away from the prop. I'll probably go with 12x12 on outer panel when I put some back on. -McG

[shine]

Originally Posted by csurf

Looking really good.. Where did you get the trim?

from this place: E-DIGITAL ELECTRONICS

I had never hear of the website before, but I found them doing a google search by part number. The price was low, maybe too low I thought. sometimes the too low price is because they are out of stock. But they arrived just fine, $659 which included the tabs and the nicer back lit switch.

[csurf]

LOL.. thanks for the response but I was wondering where you picked up the trim for the gunnel, great price BTW on the tabs.

[shine]

I picked up the trim at the marine surplus store in Ft. Pierce. It does not match well, but I plan to get coaming cushions covers around.

[Capt Chuck]

Originally Posted by shine

I picked up the trim at the marine surplus store in Ft. Pierce. It does not match well, but I plan to get coaming cushions covers around.

Two Coats of Signature Finish and Wham Bam Thank You Mame

[shine]

nice!