FB power - opinions wanted!

[redemn93]

like i said before, everyone who says they dont need so much speed, just be lighter on the throttle.  always better to have the power, just in case.

[hookdup]

Thanks again y'all!  

Happy Independence day.

[Capt Matt]

Once u get a flat back boat over 40mph your on your own, it's a out of control feeling and no fun
I50 4stroke merc is the quietest and most reliable outboard I've ever owned and perfect on a 22 or 24
Flat back

Capt Matt

[Jack Hart]

My project 22.2 flatback came with a 370# Ocean Pro 150.  It leaps onto plane like nothing I've ever owned before (and I've owned a lot of flats boats) and tops out at about 40mph. Keep the weight off the rear end, save gas and run a light 150 or 175 2-stroke.  Do you really want to go faster in a flatback?  Isn't running shallow the most important attribute?

[gran398]

Excellent point.

Because it is so easy to plane (1 degree deadrise), high HP is unnecessary. And potentially detrimental.

Ran a '67 with a 115 Yammie V-4, open transom. That torqueing 2 stroke was all she needed. Totally original....and yep a bit overweight from absorbed water. Even still....she ran sweet as a honeybun.

Add a closed transom, Bob's hydraulic jackplate, tabs with trolling motors, power-poles, tower, etc....you'll need more HP and weight to move weight.

The above is an example of Tampa rigging. Sight fishing for tarpon, shallow casting for snook, larger parties, etc. Other locales, your power needs  will be less. Open transom, clean boat with no weight....she'll get up and go with a 3 cyl. 90.

Matt runs his everyday as a top SoFla  guide....if he says a 150 is max with a closed transom, good enough for me.

[GoneFission]

OK - here's my idea - put a 200HP outboard jet on!       Think of how skinny you can get with a flatback jet!   :bounce:   You could run in a few inches of water - Merc has a 200 now:

https://www.mercurymarine.com/en/us/eng ... ifications  

Video of running skinny:
http://www.youtube.com/watch?v=rWeqd0hVJkQ  

Another option - put a jet foot on your 150-225 - maybe find a motor with a blown lower unit:
http://outboardjets.com/download/jet_dr ... 202014.pdf

[gran398]

That vid is the deal! Love the dog panting at the end

(Probably panting for Pampers after that run)

 

[Showtime7]

Anyone use twins on a Flatback?

[gran398]

They used to run twin 55 hp Homelites

[RickK]

The FBs run fine with a single 70 or a 90 on it so dual small engines should do fine, as Gran said.  The preferred engine HP on a FB seems to be 150-175hp.  So duals up to that hp should be fine, except duals will weigh more than a single of the same hp.
Gran you have dual 75's on your 12 degree Osprey - how does it run?

[gran398]

Thanks Rick. I have been very pleased with the performance of the 75's on Miss Delmarva.

I like the reliability aspect, and ease of maneuverability at the dock. The numbers are good too. WOT is 39.4 mph on the GPS, cruise is 29 mph at 4200 rpm, mpg at cruise around 2.2. Wish that part was better but its not a biggee. Hole shot is good, and she'll run on one engine 26 mph WOT.

Installing twins on either a rebuilt flatback or 12 degree requires some planning. Everyone raises their floor height on these boats to improve self-bailing. The downside, with an open transom, is that you must take into account the lower bolt-holes for the outboard(s).  Last thing you want is to have to deal with those bolts down in the bilge. That is one of the benefits of a closed transom build running a hydraulic jackplate.

Another consideration with twins on an open transom boat with the floor raised.....where the lower unit planes (tabs) end up in relation to the hull. No manufacturer makes a 25 inch shaft below 115 HP. So you either run 25 inch shafts with twin 115's and deal with the extra weight, or you call Bay Manufacturing and order 5 inch lower unit extensions.

Here is a rebuilt 240 Seahunter with Bay Mfg. extensions