21' Sanger Alley Cat

[summitrider1]

Good Morning, I took my boat out for the first time this year and had some problems getting it on plane. It is a 1983 Sanger Alley Cat 21'. It has a 1985 Evinride 300 with the blue land and sea heads. The boat will start to plane and then break the prop loose. I try to keep it around 3k rpm to grip. Any more rpm it cavitates the prop. I first tried a 24 pitch through hub exhaust cleaver and it would not plane. Then I tried my 27 pitch mazco that is over the hub exhaust and it was even worse. I then took out the exhaust plate at the back of the motor to see if that would help the prop grip, it did not. I then put a 21 pitch through the hub exhaust on and it would finally plane. Still hard to get it to plane but it did get up. Boat had roughly 20 gallons of fuel and about 600 lbs of gear/ people on board. Can someone please give me some insight on what type of prop I need or other information I need to post to figure out how to get this boat to plane easier. I am in Denver Colorado so elevation is around 5280 feet.

[vnemous]

Many high performance boats you have to slip "cavitate" the prop to get on plane. Mine for instance works best when I stab the throttle to about 5000rpms, prop breaks loose "cavitates" than drops and off I go. No disrespect but is this your first performance boat? For a first timer its a little un nerving and takes some getting use to. Thats why many thru hup probs have vent holes to form a pocket of air for the prop to free up in so it can get on plane. The more pitch the prop is the more venting it needs. If your motor is healthy you got plenty there to turn a 27p probably more than that just gotta let it vent. JMO

[summitrider1]

Yes it is my first high performance boat. I tried to stay in it for a few seconds and the boat almost came to a complete stop. I will try again tomorrow morning with the 27. I will attempt to stay in it longer when it starts slipping and see if it will eventually grab. I will update tomorrow and let you know if I had any more luck. Thank you for your advice!

[eli]

the higher the motor = worse time to plane i always wondered it a 20 lb weight in the nose would make a big deal in planing over nothing when we had 6 in my 23 daytona one person would have to stand and lean over windshield to help plane otherwise it would just dig a hole had 18 inch set back motors were so high with remote pickups just skegs were in the water at speed ,was fast tho ,my 22 twister i just trim in run to 3k it planes ok as soon as it rolls over i trim and go thinking hang a 20 lb weight in front eye see what happens wrap it in something so it dont bang hull

[KIRCHNER]

planning with a jacked-up motor takes a little finesse. u have to work the throttle. my proven system; from idle hit it just to stand nose up, back off wait for back wash to roll in hit transom stern will lift then hit it hard to3500 4000 back off hit it again and im gone. once you get it right it becomes second nature. i do it now with no neg trim. this is with a over-hub chopper. try it, youll like it, ART

[KIRCHNER]

Yes it is my first high performance boat. I tried to stay in it for a few seconds and the boat almost came to a complete stop. I will try again tomorrow morning with the 27. I will attempt to stay in it longer when it starts slipping and see if it will eventually grab. I will update tomorrow and let you know if I had any more luck. Thank you for your advice!

IT wont eventually grab. all my props i send out for more cup those factory wimpy cups dont cut it if you want to run high. only 1 was scorpion now thats a real cup. run it right out of the box. killer prop thru-hub.....

[TMI INC]

That sounds like a sweet ride, love to see a pic !!

[eli]

planning with a jacked-up motor takes a little finesse. u have to work the throttle. my proven system; from idle hit it just to stand nose up, back off wait for back wash to roll in hit transom stern will lift then hit it hard to3500 4000 back off hit it again and im gone. once you get it right it becomes second nature. i do it now with no neg trim. this is with a over-hub chopper. try it, youll like it, ART

going to try it next time out

[summitrider1]

Great thank you for the advice. I noticed that the boat was missing the trim tab on the lower unit. I made a make shift cavatation plate and it will get on plane now without cavatation.

KIRCHNER- it's funny you mention that technique, I attempted that and still couldn't get it to not blow out, It got really close but just wouldn't keep hooked up. Now with the anti cavitation plate it hooks up very good.

[summitrider1]

Here are some pics TMI INC.
As far as I can tell it's the only center steer alley cat 21 that jack ever made.

[KIRCHNER]

my 62 mag-cat has left side steer and was mississippi marathon winner with 2 80 mercs, 19 hrs average 52 mph. same as a power-cat. got it goin 79 gps with 1 2.4 mariner mag 220. 16' pics are on my profile/ album ya gotta check them out. im not too good with posting pics i should trade in my flip phone but it matches the boat! LOL ART. MAGNOLIA CAT PICS SHOWN with 150 did 66 mph with dennis 22 chopper. winning boat was 1958 model but same hull i have all documentation and articles old ads , pro-mo stuff from mercury magazines.

[TMI INC]

Wow!! That sucker looks mean. I had a chance to buy one a few years back from and S&F member but I couldn’t pull it together in time. Lol

Thanks for posting the pics