question for all you flatbacks???

[james c]

I have a 1967 222 flatback totally restored besides for the paint. the boat was rebuilt with ultratec and nidacore i put a 55gal fuel tank under the deck and moved it all the way up to where the deep vee starts. the center console a baught for it is only about 3/4 the size of the original. the console gives me more room for the full tower. the console was also moved up about 3 feet from the original. the reason for this is to offset the weight of the porta bracket and heavier motor. want to try and keep the boat nice and evan when it's in the water. This is the question does the flatback go just as fast with a 150hp vs 200hp??? i was told that the flatback only gets up to about 38mph before the bow starts to dive and keeps the boat from going any faster. Is this true???? if so im not going to mess with a 200hp. I would love to know what my performance would be with a 150hp four stroke and then with a 200hp hpdi or e-tec. Does my boat need any more then a 150hp four?? is there anybody out there who can advise??

[scott_gunn]

There are many people in your area who probably know this answer.  One person to definitely call would be Tommy at Hammerhead Marine.  He has restored many Aquasports (or so I hear) and could probably give you the answer.

Let us know what you find out.

[gotoml]

I have a 67 FB that I am restoring and I am going with a Yamaha 150 hp, I just haven't decided if I am going with a 2 or 4 stroke. They are all close in weight with the HPDI (2S) about equal to the 4S and the high power 2S about 40 lbs lighter than the 4S. I would like to see what you end up and any feedback on the 150 2 strokes vs 4 strokes. Also, can you post pictures of your 67, I'd like to see what you have done.

[james c]

i will post new pics when it's done being painted. By the end of sep it should be done. I have been doing alot of research of which type of motor to go with and im starting to lean towards the 175 suzuki fs vs the verado 175. cant beat true cubic inch!!! if i do go with the suzuki i will have to wait untill January... tell me about your rebuild?? tower? full transome? what type of material? Im still waiting for an anwser to my original question so if you find anything out please post it. thanks james c. Do you know of any true speeds that the hull is capable of and if so with what hp?

[fishbonz]

I have a 1972 flatback with a 200 HPDI VMAX with a full tower (see my photo gallery).  The boat tops out at just under 40mph with me and a full tank of gas.  I'm not sure I would lose much speed with a 150.  What the 200 gives (for the same weight as a 150 HPDI) is a lot of acceleration and a hell of a hole shot.  To be honest, I'm not sure I'd want to go more than 30 mph on a routine basis.  The boat just gets too squirelly above that.  Also, with the motor jacked  up (no portabracket, just a jack plate) you really need to watch for sliding.  There is nothing in the water to hold the stern in place in even a gradual turn.  These boats were designed to carry two 60hp to 70 hp motors in the old days so 150 is probably great.  Check with Capt. Flatback.  He has a 150 Honda and can give you an idea of performance with that engine.  Charles Chunn has a 150 Yamaha 4S.  Both are forum members.

[captflatback]

Hi Guys,

Will the boat is 99% done thanks to Tommy at Hammer Head he did a killer job. The only thing is getting the boat proped right i'm on prop # 6 and getting ready to go to the water now to test a new one. The question 150 or 200 hp i put a 150 Honda on the boats max speed is around 42 ( not mine ) thats the fastest i,ve heard i'm at 40, so go for the fuel mpg. I'm  running about 5 to 6 gal per hour @ 4200 rpm alot better than the other boat.The boat is coming out of the hole better with a bow lift 3b 17p am now going with the same prop but a 16p vented i think is the right prop. A buddy of mine has a 24 proline 150 Honda flys out of the hole and tops out around 44 mph with the same prop, so i think a 150 is all you need. I'll get some pics up in the next few weeks.

Captflatback

[fishbonz]

I run a 4 blade.  I'll post specs this afternoon.  Also, I checked my records.  Fastest was 39.5 mph on a flat calm day on the GPS.  I could get more speed from a different prop, but I'm really not sure you want it on this boat.  I cruise at 4300 RPM and I'd guess I'm running 28 to 30 mph.  I am definitely overpowered but when has too much power ever bothered a real man.

Also-  Charles' is not a flatback so his performance may not be comparable.

M.

[james c]

Well it looks like the myth stands true!!!! 38mph on a flatback is all your going to get and as fast as you would want to go. I am taking the advice seriously. I don't need speed just good mpg. I bet the ideal motor would be a 150hp four on that hull. You have to be carefull when it comes to those hull's that slide around on you!! And that's comming from a previous owner of a Carolina Skiff. I wonder if there is any way to help that hull dig a little better? Maybe extend the baby keel to the stern or bat wing style trim tabs. Im just thinking out loud. probably not going to help!! I have to say thanks so much for the advice it was exactly what i wanted to hear ( the boat needs no more hp then a 150). But still keep the opinions comming!!!

[Radioshop]

"I wonder if there is any way to help that hull dig a little better? "

Sure, buy the 72 or later hull with more deadrise.....  Just kidding....  I would be leary of adding strakes and/or keels.   The batwing tabs might work.

[captflatback]

Use a stern lift prop or make the keel longer or put in 2 outer keels at a angle that will stop the sliding. The only problem with a stean lift prop the hole shot and your top end speed will come down alot.

[fishbonz]

Jim-  What's a "stern lift prop" and how does lifting the stern give you more control whent he stern wants to slide?

[captflatback]

It put's more of the boat in the water it makes it run flat. It will put the v douwn in the water. The bad thing is when you run fast the boat will bow steer.

[james c]

by moving everything foward I hope that alone will make the boat run pretty evan.

[Anonymous]

Jim -  May I use your "trial and error propping" for my 150 Honda when Tommy gets it done?  My 1977 22'-2" is going in around mid Oct - it'd be nice to know ahead of time what prop works the best with that boat/motor combo.

Thanks

[captflatback]

Yes but don't you have a the Dorado hull with the 12 d. I just finshed trying the new prop and the boat comes out of the hole good now and for speed i'll have to get back to you my new 111 Lowrance will be here on friday so i'll give you guy some numbers next week when i get back from scalloping in Steinhatchee.

Jim Lemke