To cone or not to cone, that is the question

[175checkmate]

I am going to throw this out here.
I am thinking of adding a Bob's cone/low water pick-up to my lower unit.
I understand that that they really help above 80mph and that I may not get to that speed.
But I need the low water pick-ups. I can only go so high with the motor with the factory pick-up's. I am going to plug the top 4 holes in the LU and this should help.
So what do you think.
To cone or not to cone. That is the question.

http://www.checkmate-boats.com/6/ws/,s,8626072361/avatars/rooster_3.jpg

1975 Checkmate Tri-mate 2, 2.4 200+

[175checkmate]

I am going to throw this out here.
I am thinking of adding a Bob's cone/low water pick-up to my lower unit.
I understand that that they really help above 80mph and that I may not get to that speed.
But I need the low water pick-ups. I can only go so high with the motor with the factory pick-up's. I am going to plug the top 4 holes in the LU and this should help.
So what do you think.
To cone or not to cone. That is the question.

http://www.checkmate-boats.com/6/ws/,s,8626072361/avatars/rooster_3.jpg

1975 Checkmate Tri-mate 2, 2.4 200+

[Bill]

I say no cone, it will probably slow you down 1-2 mph and may cause blow-out. If you do not know this already, when you plug the holes, make sure the gearcase is apart so when you put epoxy in the pick-up, it does not go inside the screen and plug the water passage. I know someone who lost a powerhead that way, no, not me and the dumb a** did not have a pressure guage

[175checkmate]

I have heard the same thing. I was thinking I may be able to compensate the loss of bow lift by getting more of the motor out of the water.
My LU has removable inlets (1978 175hp) And yes I will take it off when I plug them.
I still can't believe people raise the motor with out a water pressure gage installed. Always seemed like a no brainer to me.

http://www.checkmate-boats.com/6/ws/,s,8626072361/avatars/rooster_3.jpg

1975 Checkmate Tri-mate 2, 2.4 200+

[Woody]

What is your shaft to pad dimension? How much trim do you need to carry the bow?

There are 3 things to consider; water pressure, drag and bow lift.

You should block the upper water inlets before assuming you need lwp. It will need to be done anyway. Watch your wp gage.

Drag can be reduced with a $15 Vance cone on the bullet. The Vance cone is also lot easier to install than a big foot. The bow lift would not suffer because the gearcase won't have a cle shape.

Raising the moter or a cle cone will reduce bowlift. If you need more bow lift you would be better off with setback than a lot of trim.

[Bill]

Woody is right, by raising the motor, you take away from the props ability to provide lift. You have less surface area of the blades providing lift, hence more set back owuld work better. With that 3 inch transom, you should be alble to put 20 inches http://www.checkmate-boats.com/infopop/emoticons/icon_eek.gif Yes JW, you heard it out of me, more set back http://www.checkmate-boats.com/infopop/emoticons/icon_wink.gif

[Chris]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Bill:
Woody is right, by raising the motor, you take away from the props ability to provide lift. You have less surface area of the blades providing lift, hence more set back owuld work better. With that 3 inch transom, you should be alble to put 20 inches http://www.checkmate-boats.com/infopop/emoticons/icon_eek.gif Yes JW, you heard it out of me, more set back http://www.checkmate-boats.com/infopop/emoticons/icon_wink.gif<HR></BLOCKQUOTE>JW, looky here, you've converted Bill to the church of setback! http://www.checkmate-boats.com/6/ws/,s,8626072361/Graemlins/thumb.gif

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[175checkmate]

My old set up the prop shaft was 4" below the bottom of the boat. This was as high as the hyd. jackplate would go. Almost zero trim gave me the best top speed. Still had great water pressure. When I re-rig the boat I will be able to mount the motor 3" higher on the transom and the new jackplate will go 4" up from there. I am going to plug the top holes of the factory water pick up's and I will try that before I think about a cone.
20" setback, geesssh the boat is only 16'.

http://www.checkmate-boats.com/6/ws/,s,8626072361/avatars/rooster_3.jpg

1975 Checkmate Tri-mate 2, 2.4 200+

[JW]

If you get top speed with neutral trim, then you don't need any more setback. Raising the motor up will definately gain you speed until you lose prop bite and the bow comes back down. Then added setback will help, but I'd play with props before setback with your small light boat. 28" Chopper II maybe.......If you can get more speed by raising the motor TOO high for water pressure, then you can add a cone. I'd cone only as a last resort on a Checkmate, after you've done all the other mods...

[Bill]

Man, you guys just don't get my sarcasm (dry humor) I was just kidding!!!!!!!!!!!!!!!

[175checkmate]

Kidding maybe, But in the quest for speed I am just might try anything once. lol, I know the transom would support it.

http://www.checkmate-boats.com/6/ws/,s,8626072361/avatars/rooster_3.jpg

1975 Checkmate Tri-mate 2, 2.4 200+

[Chris]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Bill:
Man, you guys just don't get my sarcasm (dry humor) I was just kidding!!!!!!!!!!!!!!!<HR></BLOCKQUOTE>Dry humour? Dry humour? We all have water pressure gauges, it's no wonder, we didn't get it! http://www.checkmate-boats.com/infopop/emoticons/icon_razz.gif

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[Bill]

Chris, your good, where do you come up with those? http://www.checkmate-boats.com/infopop/emoticons/icon_biggrin.gif