I have had both types and on the smaller boats where you want to "extend" the running surface so to speak, the parallel way worked best for me. I could use the tabs to flatten the running attitude in a following sea and just slice through the waves.

On my 38 Donzi I have the same size 280 tabs that were on my 29' Kryptonite, but they are mounted horizontal. I haven't felt the need for extra length and they are perfect for just putting that little bit of correction in where you need it.

IMHO - The best mounting configuration is parallel with the angled edge to the lateral side of the boat. The reason the horizontal method is used is to eliminate the lateral DRAG that is caused when square or right angle tabs are put in the down position. With your boat out of the water drop your tabs, then go forward and look back. You will be surprised how much of that tab is deflecting to the side vs. in a downward angle. Side deflection does nothing for you boat - but slow it down. With the notched or angled side of the tab to the outboard or lateral side, you eliminate that lateral deflection. If you swap sides - the straight side will now be medial (Inboard)- make sure they clear your props at full turn...

Hope this helps.

Depends on the throttleman. Jason does it totally differently..the way Bobby Sheer and Keith Hazell taught him...and it seems to work OK :D

Neutral drive (or even a touch positive or negative) plants the ass of the boat, dropping some tab plants the bow. Nice level flight without any of the transom hop caused by tucking the drive in too much.

Just to get a feel for that method first hand. If i dont like it i know a glass guy that can fill the holes back in :D

Seems that a lot Fountains especially the singe engine apps have the tabs mounted horizontal. Also seems like a lot of Warlocks mount them horizontal and further inward away from the chines. I understand it is mainly about reducing drag along with hull bottoms can react differently from brand to brand but wonder if there is another big reason for horizontal mounting. Maybe Reggie III could chime in about the Fountains.

Thanks for all the input so far! I am still undecided at this point.. However, I am leaning towards the horizontal set up.. Keep in mind, I am placing 280 K-Planes on a 21' boat. I know there overkill but I hate Bennets with a passion... I will not put Bennets on my boat.... I am thinking with the 13 inch set back I have on the engine, placing them parallel to the V may scrub some precious speed even with them in the full up position... I go back to the image Dave posted... I think this would give a good resolution on trim effectiveness vs. travel since the 21' should not need much.... Pretty much only in rough water to help keep the bow down... I guess if I go that route and dont like, I do know a glass guy also....... :)

Curious about this as well on Fountains.

Also remember that if you put them parallel with the water and on the outsides of the transom they will be much higher out of the water when running at full speed. If you need tab at that speed you will need the longer tabs just to touch the water with them. From the keel of your bottom to the new location is a big difference in height. I measured I would need aprox 6" longer on my tab to do the same thing. In a nut shell don't even try it with short tabs IMO. Also if you need full tabs to get on plane this also could be a problem.

I mounted mine parallel with the intent of extending the bottom.

Another option is mounting them horizontal, but down at the lifting strake instead of out at the chine, if you have room between the strake and the engine.

This is how I opted to mount mine after a bunch of research and testing. I like how they work...

I also switched to 30" plates with good results as well, I will go back to my 24s though..