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Getting on Plane....


JakeyBaby

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I am in the process of upgrading lots of things on the boat before this coming season! One of the things i would like to try and make a little better is getting my boat up on plane faster!!!! I have a 1987 22ft Cris Craft with a 4cly. mercruiser pushing it(180 hp), with the Alpha One lower unit. I was wondering if changing out the factory i guess i would call it a "whale tail".. not sure exactly the name. But it is the tail looking thing on the lower unit just above the prop for the prop wash. The one on the boat now, barely covers the dia. of the prop. Is it supposed to..?? My guess is the more down force that it pushes out the faster you would get on plane which also means not burning as much fuel!!!!!!!!!! Any suggestions would be greatly apprectiated!!!

Thanks Alot

Matt

-Jakey Baby-

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The Whale tail as you call it is just fine and it is not your problem. It may be your propeller or the way you divide the weight in your boat.

As for the propeller, it may be too worn or too damaged or just plain the wrong size for you your rig as you have set it up. You must check the owners manual on your engine and find what the ideal rpm is for your engine.Then compare your real time rpm to what it is supposed to be.

Another thing that may help is "trim tabs" these adjustable tabs will help you get up on plane faster.

Then there is the weight thing. Make sure you do not have water soaked foam under your boards. this can add hundreds and hundreds of pounds of dead weight to your boat. There are a lot of other factors, but this is a start.

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I would say trim tabs would solve your problem my boat would not get out of the hole without them then you could mess around with different pitched props you can also use the trim tabs to adjust the boat to one side or the other depending on weight distribution good luck

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Props with a cupped blade even though they are the same pitch make a differance too. I had two props the same pitch . One with regular blades , one with cupped. I couldn't troll with the cupped blade , was to fast. The top end was higher and the bite out of the hole was greater than the regular blade.

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i agree that the prop may be a problem but 180 hp isnt a lot shoving around a 22 foot boat rigged for fishing...i'm guessing the boat was never a race day winner but runs ok and youre just looking for something to get it up on plane quicker than it has in the past...

if you are running in your recommended rpm range with your current prop the whale tail isnt a bad place to start from an economical standpoint...although trim tabs have many advantages under different load and weather/sea conditions...

in my experience with 2 previous boats...penn yan 21 tournament with 175 hp merc and 245 hardtop with 205 hp merc a stingray hydrofoil on the lower unit snapped the boat on plane faster, increased top end speed and fuel economy...the time to plane was the biggest improvement and very noticeable...

its an inexpensive thing to try and ive had good results with it...

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I figure that 4 cylinder is likely not enough butt to put you up on plane.

I will give you a little for instance my 19 foot deep vee boat with a 115 merc on the back will take 2 people and my 40 gallon bait tank a flying out of the hole.. add 2 more people to the mix, another 400 pounds.. and it labors like hell to get out of the hole and drinks gas like it is free.. This is running a 17 pitch prop. Rpms do not get near the powerband.. Dropping a 15 pitch prop on there and it will hop out of the hole and run in the desired rpm range and consume about half the fuel.

You might need to just simply replace the prop with the next lower pitch to gain some power.

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Thanks for ALL the advise to all. I am going to try and trouble shoot this problem with the advise you guys have provided. Another ? i have if i do have water log in the foam like you guys mentiond, is there any way to help dry it out..??? Or am i just F%&*d? Because im thinking it is possible that i do because when i do get up on plane the boat pulls to left religousley!!! I have tried to play with my trim tab anoid above the prop to help this, but no real differnce. Thanks Again!

Matt

-Jakey Baby-

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Take off the whale tail and give it a try then. It should only be secured by 4 bolts. Whale tails are of help to only a handful of hull designs. It is not factory.

As mentioned, weight distribution is always to be considered. As is a waterlogged transom.

If you cant verify that the propeller is correct, borrow a stock one from someone with a similar engine package. Trial and error is the only way to select a prop. Period.

Not mentioned, but something I have run into: Alpha one (gen 1) outdrives all look the same, however there is at least 4 different gear ratios. If it has been swapped for a v8 version, she will act like you are towing your anchor.

Your boat requires a 1.84 ratio drive. PM me if you need more info on determining this...

Pulls to left huh? When you hold the wheel straight is the boat tipped to left? This would indicate a trim tab is stuck. The trim tabs are flat aluminum panels affixed to the outboard edges of your transom. They will have a small hydraulic cylinder attached to them.

The anode above the prop is not adjustable. It is sacrificial metal to attract corrosion. It is not a trim tab.

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There is a trim tab right behind your prop that is adjustable. It looks like a little rudder and there is only one bolt that holds it. Loosen that bolt a bit and turn that trim tab a bit to the right,then tighten the bolt again.That should help her to go straight

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Yea the trim tab that is also anoid held in by the single bolt that helps hold the upper and lower unit together is the one that i have played around with rolmops. No real positve results thou. The boat just seems like it almost wants to roll over on its left side especially in rougher water, when motoring.

Bullgator, my boat does not have the trim tabs that are bolted on each side of the transom that you are talking about. Yet that is!! Pullin the whale tail completely off can help more then hinder really??? Never gave that a thought!

Thanks Matt

-Jakey Baby-

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There is a trim tab right behind your prop that is adjustable. It looks like a little rudder and there is only one bolt that holds it. Loosen that bolt a bit and turn that trim tab a bit to the right,then tighten the bolt again.That should help her to go straight

If the boat (wheel) pulls to port (left) . Rear of the tab should be turned (off-set) to the left to cure or help compensate for it.

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If I might add my two cents... Being an owner of a 22' Chris Craft Scorpion with a godforesaken 3.7L Mercruiser.

The only reason our boat even gets on plane is because of the trim tabs someone mounted on it years ago. After 30 years I'm sure the engine has lost some uhmph so that is part of the problem. But with just 2 people in the boat, and not putting the tabs down, the boat will just stand on it's stern forever. I know our boat is prop'd just fine. At WOT it tachs between 3900-4000 depending on weight.

Now add the tabs into the mix. Night and day. Will get on plane in no time and man are they nice for leveling the load. Nice on rough days too.

As far as foam. I don't think our model has any more foam then just a little around the gas tank. Even saturated I don't think it would hold more than a few gallons.

My opinion is that our boats just shouldn't have been sold with anything less than a V6 with options for larger and nothing smaller. They may have been sufficient from the factory, but unlike wine they don't get better with age.

Now my buddy's boat(same exact hull with the outboard option) has never had a problem... Except when you throw 5 people on it. His is only powered by a 115 Merc and no tabs. Probably helps when you loose half a ton from the stern of the boat. My uncle has the Scorpion CC(again same hull) with the 305 I/O and no tabs. I have been on that boat being 1 of 6 people and it doesn't even hesitate. Food for thought.

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put trim tabs on and your problems will be solved when you learn how to use them. I have the lenco electrics and love them. I can have 3 guys on the port side of the boat and I make the adjustment in the tabs and my boat is running even. If i put the tabs all the way down before i throttle up the boat is up on plane instantly. If you put them on you have to play with them and learn how to use them.

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More horsepower would help, but probably not an option.

A properly sized and pitched prop will help.

Trim tabs will help.

The StingrayHydrofoil will help and will be the cheapest of all the possible solutions.

I had a heavy '87 Sportcraft with a 4 cylinder and the StingrayHydrofoil solved my hole shot very inexpensively. I also re-distributed weight forward also.

The guys at Propgods.com are the real deal concerning props. I've never heard a bad word about them. They will advise to the prop you need, and will swap that prop until you find the best one for your boat and hull.

Good luck.

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180 hp is not a lot for a craft of that size. If you are going to spend a good amount of time out there & travel a lot to/from spots, trim tabs will help a LOT for hole shot & ride leveling. Came w/ my boat & w/ 5 guys on they are great. Also I would go down one size pitch of your prop( I took Spinellis advice And did just that w/ good results). Less wear on the engine & gears & if you are trolling it will give more control & also help keep your RPMs up to keep your oil pressure up to help extnd your engines life. You will lose a little top end but hey, It's about the fishing. Besides ,if you don't have a spare you really should get one.

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You have been given allot of good advice, but just start with knowing what your Red line is of your motor, and make sure your tack is accurate. they can be really off, many are not real accurate, but you need to know within 200 rpm, 50 is better.

With the prop and the load that your going to consider "normal", you should be (in calm water no wind) able to just get it to the red line. It should not happen fast, and you should not be able to go over it. Your Wide open Throttle is (depending on motor) 500 to 700 RPM slower, and your cruising speed is factored by Plane, RPM, and speed. Thats normally another 500 to 1200 rpm lower than your WOT, but you figure that out after your prop-ed right.

If you can not reach red-line, your over propped, if you get to red-line to fast or can go past red-line easy your under propped.

Get this right first, then work on the plane and trim. Other wise you will not be doing it right.

I do think you have plenty of motor for your boat, if its lower unit is geared correctly. You can check that if its suspect. I bought a used boat that the owner put what ever lower unit on it he could find to sell it and it was geared wrong, so it can happen.

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The question about your rpms is a good one...what are you turning while trying to get on plane? At WOT? and what is the recommended WOT range? If you are not turning the recommended rpms at WOT then you definitely need a lower pitch prop.

Also how many blades is your prop? A 4 blade will lift the rear better than a 3.

Lastly, no one has mentioned the advantages of a vented prop in helping you spin the prop up higher and help you get on plane better even if you are correctly pitched for on-plane WOT. Using those correctly made my would-be sluggish dog of a boat literally jump up on plane. Suggest reading up on mercury prop's PVS system. Getting a prop with these vents is a lot cheaper than trim tabs if you have to buy a new prop anyway.

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