9.8 merc with hydrofoil???

quick question that im sure has been asked before but im going to ask specific.... i have a 9.8 mercury thunderbolt 110 mid 80s i believe, i have it on my 12ft mirrocraft, if i put a hydrofoil on it would i see much better performance??? should i be getting on plane somewhat in a little boat like that???? any info you have is much appreciated.

Thanks!!

A 9.8 hp should plane a 12ft boat easily. Unless you have to much weight in the back or your boat weighs 500lbs?. Ballisting your boat properly can make a big difference. Also having the correct prop on the motor can be very helpful to performance.

I am not an advocate for whale tales or hydrofoils. They will take away from performance usually. They are designed to create stern lift similar to what trim tabs do. But trim tabs do it way better and safer than a hydrofoil. If you don't have your motor exactly the correct height a hydrofoil will do nothing for you but cause drag. Theoretically they allow you to plane at a lower speed.

A 9.8 motor can plane a 16ft tin with an adult in it. I planed my 14ft tin with myself, 2 kids and some gear with ease.

im wonderin what the problem is then??? it just doesnt seem to get on plane.....

You may have a number of issues that are preventing you from getting on plane. The very first thing to do (as already suggested above) is to move your weight around to balance out the boat. Batteries and gas tanks can be moved up front to help out.

Check to see if you have your motor "tucked in" i.e. have the motor shaft leaning forward, moving the prop toward the front of the boat. That helps in getting up on plane. It will slow the boat down, but planing will speed it up. The right spot is often elusive. Just try different settings on your tilt holes until you get the right one.

I know nothing about the "right prop" so talk to a prop shop and see what they tell you. Many shops will allow you to try a prop, then swap it for another if the first one doesn't do the job.

As said above, tabs work far better than "tails". Read all you can about tabs. Go to the Smart Tab site and watch the videos. https://www.nauticusinc.com/smart_tabs.htm

Some guys on here have built their own version of tab systems.

Rich

I used to have a 12' flat tin boat with a 9.8 Merc years ago. It also would NOT plane. Put that motor on a 14' boat that I bought and it would plane very easily. Nothign wrong with the motor or prop. The boat just would not plane.

For giggles we put the neighbor's 200 Merc (20 hp) on it...still would not really plane. We concluded something was up with the hull shape.

re Hull shape...Some hulls, often due to being left on a too short trailer...with properly supporting the transom..., or a variety of other issues, can develop a "hook". That is a downward tilt of the bottom of the boat hull near the stern. Some hulls actually have a slight hook designed into them.

Getting up on plane with a hook is just another confounding thing about boating. A hook helps keep the bow down, but, I'd guess, if the engine's power wasn't sufficient, it couldn't overcome the downward thrust of the hooked hull

regards, Rich

Well im officially stumped! Not too sure what it could be... maybe smaller boats dont plane well???? frustrating......

Smaller boats should be easier to plane than larger boats. Something is going on. Without being there and moving stuff and checking stuff .... who could tell. Rich