what angle should i setup to plane in water?

[jabboo]

what angle should i set the motor to so that it planes in the water?<br />its a 20hp chrysler motor from 1976 i think.<br />on a 12ft tinny

 

[JB]

Re: what angle should i setup to plane in water?

G'Day, Jabboo. On small boats with small engines that don't have adjustable trim the general rule of thumb is to set the anti-cavitation plate even with and parallel with the bottom of the boat. <br /><br />You might try setting the foot out a notch or two to get more speed. When you get cavitation or porpoising you have it tilted out too far.<br /><br />Some people raise the engine a notch or two to get more speed. Again, cavitation or porpoising is a sign of too much.<br /><br />Good luck.<br /><br />Red sky at night. . .<br />JB

 

[evin300]

Re: what angle should i setup to plane in water?

Sounds like a lot of HP for this little boat, my gut says this could be too much, even after taking into account the propshaft vs crankshaft HP rating.<br /><br />I have never run over 10 propshaft HP on a 12' aluminum, so as you can tell, I have no experience to stand on, maybe others can guide you on this. Planing shouldnt be a problem with this set-up, JB sums it up really well.<br /><br />What HP is the boat rated for?

 

[jabboo]

Re: what angle should i setup to plane in water?

dont know what hp the boat is rated for <br />looks to be a modified tinnie<br />its 12ft <br />and has a worn sticker on the side that says <br />stacer 3.4 <br />the boat is 3.4m in length<br />and has 14 crossbars on the floor <br />plus where the motor is placed on the back that wall has 2 cross bars going horizontal along the wall.<br />and one verticle plus a bar going from the floor of the boat at an angle of 45 degrees meeting with the wall the motor sits on <br /><br />so as u can see its been heavily reinforced.<br />its an old boat and i cannot find it on the stacer website.<br /><br />plus it has 3 seats on it unlike the recent tinnies from stacer which only have 2 <br /><br />so i guess the owner before me modified it allot.<br /><br />how do i know when the boat is planning and how do i get it to plane?<br /><br />plus what is cavitation or porpoising <br />as u can tell i am new to this boating thing ( have had the boat for about 8 years but it previouisly had a 6hp motor on it which didnt really go so fast so i took no interest in the technicall side untill now cause i bought the faster motor.

 

[JB]

Re: what angle should i setup to plane in water?

Hi, Jabboo. <br /><br />Cavitation (or ventilation) is when the prop starts pushing air or foam instead of water. You will lose speed and the engine will rev up.<br /><br />Porpoising is when your bow starts rising and falling uncontrollably. Can be quite dangerous in a small boat.<br /><br />Red sky at night. . .<br />JB

 

[wippb]

Re: what angle should i setup to plane in water?

Cavitation

 

[Ross J]

Re: what angle should i setup to plane in water?

"How do I know when it's planing" - <br />When you start off your boat is sitting "down" in the water, the boat is in the water the complete length of the boat and it goes rather slow. As you increase speed the hull trys to lift out and "plane" on the surface. At some stage you'll find the boat appears to suddenly pick up speed and sits much higher on the water. You may even have to throttle down a bit to keep a safe speed. This is planing. Believe me mate, you'll know when you're planing.<br />Ross