Cougar 21' + Vmax SHO question

[jimmybrie]

These are very nice boats you have there guys! Impressive how the 22 Liberator's back end still floats well with that weight in the back!


Speed Jr.

Yes I agree I will wait to see the performance at full height to tweek the setup performance wize... but still I don't like that porpoising at low speed and I would like to get rid of it... so playing with weight distribution might be a good lead.

Btw what speed the 22' with 450R? Must be crazy accel too!



Billy Bilt,

What brand is that bracket ? Mine is an old steel one modified and it's got 8 bolts but only on the inside. Bigger motor and setback stresses the transom so I might be looking at improving that also.

Is the 300R exhausting in the mid so you can run an over hub?

Your rebuilt seems very clean btw !

Thank you guys

[jimmybrie]

you're chasing your tail without solid mounts, you won't believe the difference!!! yes power head has to come off, all you will need is a new base gasket. Wayne Worthy sells the mounts. Until you get it sorted out, only change one thing at a time, takes a little longer but in the end you will have leaned what actually worked. After the mounts are in and you've tested, go up where center line of propeller shaft in 1/2 below, test again watching water pressure, SHO will not make the kind of pressure you're used to, barley anything at idle. 15-16 or so full throttle. As far as balance concerned since you don't have that information, trail and error, a sand bag will work temporally. I found my solution by accident, boat had inline seats with a 260 friend riding one day. Boat broke over, the stern lifted, boat gained 300 RPM and 4 MPH. My engineer son saw my cave man approach to replicating the 260 friend on the flat drive way. I had batteries, chain, blocks, anything heavy. Asking what I was doing, I explained, pulled out his phone and in 3 minutes after a few questions and measuring problem solved. He Said "your need 11.6 lbs right here" pointing at the approx location the the bow eye/D ring. Boat was forever changed!! Take it slow and methodical.

Ok I see... I like the idea of adding a little weight (sand bag trial and error) in the front while maintaining the setback because like Speed Jr. I like the idea of making the boat longer.

The mounts? What benefit besides side to side stability improvement ? What is the major difference you're talking about? Why is it contributing to chasing my tail?

Thank you for all your inputs!

[GETBOATS]

LOL, I recognize the chasing thing cuz I've done it!!!

As for the mounts, they are soft so vibration does not transfer to the boat. When we ask so much from these set-ups it requires the propeller shaft remain as constant as possible. I've never measured , but the nose of the bullet has to move upward at least 1/2 inch under accel. Thats negative trim. Now think of propeller torque pulling the gearcase sideways moving again when we hadn't change steering. We want the trim to remain steady right? Well its not with soft mounts, the bullet is moving around on its own and imagine the center of the prop shaft moving when you didn't ask for it. Decel gets worse, letting out of it for a 180 turn causes the lower to move away from the transom.

[jimmybrie]

LOL, I recognize the chasing thing cuz I've done it!!!

As for the mounts, they are soft so vibration does not transfer to the boat. When we ask so much from these set-ups it requires the propeller shaft remain as constant as possible. I've never measured , but the nose of the bullet has to move upward at least 1/2 inch under accel. Thats negative trim. Now think of propeller torque pulling the gearcase sideways moving again when we hadn't change steering. We want the trim to remain steady right? Well its not with soft mounts, the bullet is moving around on its own and imagine the center of the prop shaft moving when you didn't ask for it. Decel gets worse, letting out of it for a 180 turn causes the lower to move away from the transom.

Ok I understand, it also makes a lot of sense that vertical mouvement also has a considerable effect on the boat dynamics. Will try to find some time to swap the bushings before next summer. If not it will be on the prioritary to do list. Question, are they made of Delrin or aluminium?

If I'd have the mesurements I could simply machine a set.

Thank you again for your input.

[jimmybrie]

Hi everyone,

I had posted in the Hill 5 Blades thread but I thought I would update this thread since it's also a lot about Cougar 21 + Vmax SHO. (If someone like me does a search)

Was very desapointed about my first Hill 5 blade 32p test. It was 3-4 mph slower than my Bravo FS (101 mph) and acceleration wasn't there. There was a lot of boats, wind and waves so I couldn't get the clear water I would have wanted. Only a couple little passes so I could keep it safe. So I thought I would give it another try and do the tests the way I wanted before trying another prop. I just felt the hull was too wet and I couldn't get the lift I got with the Bravo.

Got some clear water and found out that it needed way more trim to lift the bow (even if I tried it the last test felt like it wasn't responding) Did multiple passes, fine tuning trim every time. Being cautious and ready to trim down. 104(2)-106(alone)-107(alone)

End of the story I got 107.6 MPH 2 in the boat, 1/3 tank, 50-75 lbs extra gear. Stock Hill Thru hub out of the box. Maybe I could've got a little faster but I was satisfied, starting to get darker and I didn't want to push my luck.

Now I'm wondering if 18* rake and less trim would better? (I liked the bow carrying capability and accel of the Bravo when loaded)

Or maybe just cut the barrel of the 15*...?

I know I should also get the prop worked but I want to find the optimal one before.

Still the motor mounts to be done also which makes a big difference (prolly not on speed) according to some experienced SHO guys...

[JCSmile]

What did the boat run with the 260?

[jimmybrie]

What did the boat run with the 260?

With the lightly modified motor I had on it before switching around 95-98, it did ran 105 back in the days with a more modified motor probably pushing close to the same hp as the SHO turning 8500-8700.(With Gaffrig pitot tube at that time so maybe not 100% accurate) But it was more weight sensitive. The 2.5 (espescially in modified version) is still one hell of a motor!

[Speed Jr.]

Those are great numbers Jimmy. I really like the Hill TH 5 blade cleavers with the flare cut off, but keep as much of the barrel as possible or it will start blowing out when getting on plane. Ive left the first 1/4" of the flare and sanded the OD of it to keep the barrel as straight as long as possible. 95% of the time I run this prop in 30-32p. With a full load of people just cruising around I still like the Max5, which gives better low speed bow lift. Keep the rake to 15°, get the prop blueprinted and remove the flare and youll be happy. Small boats dont like ours dont like the 18°.

All the best

[jimmybrie]

Those are great numbers Jimmy. I really like the Hill TH 5 blade cleavers with the flare cut off, but keep as much of the barrel as possible or it will start blowing out when getting on plane. Ive left the first 1/4" of the flare and sanded the OD of it to keep the barrel as straight as long as possible. 95% of the time I run this prop in 30-32p. With a full load of people just cruising around I still like the Max5, which gives better low speed bow lift. Keep the rake to 15°, get the prop blueprinted and remove the flare and youll be happy. Small boats dont like ours dont like the 18°.

All the best

Thank you for the advice on rake! I'll go that way. What benefit do you find in removing the flare? Any speed gain? I thought maybe if one can lift the bow enough having stern lift also might help dry the boat even more? Most seems to like it better without the flare just trying to understand...

Yes planning on getting the prop labbed this winter. Just have to find a good shop up here. We had one near back in the days but for now only found one farther I'll continue my shearch a little.

Do you only blueprint/balance and lighten it a bit (thin the blades) or you also play with the cup?

Thank you

Jimmy

[Speed Jr.]

Thank you for the advice on rake! I'll go that way. What benefit do you find in removing the flare? Any speed gain? I thought maybe if one can lift the bow enough having stern lift also might help dry the boat even more? Most seems to like it better without the flare just trying to understand...

Yes planning on getting the prop labbed this winter. Just have to find a good shop up here. We had one near back in the days but for now only found one farther I'll continue my shearch a little.

Do you only blueprint/balance and lighten it a bit (thin the blades) or you also play with the cup?

Thank you

Jimmy

No need to thin them out, just get the blades all straight and even. The Hill Props dont have the most matched blades from the factory. I would advise not to thin at all, keep em as strong as possible. Ive been breaking/cracking blades with the 450R. The flare can create some tail lift, which I/we definitely dont need at high speeds. May be worth a mph or so removing it, nothing substantial.

I hope to get a Merc Altitude soon to test and see how it compares. It should be the best of both worlds for an overhub cleaver.

[jimmybrie]

No need to thin them out, just get the blades all straight and even. The Hill Props dont have the most matched blades from the factory. I would advise not to thin at all, keep em as strong as possible. Ive been breaking/cracking blades with the 450R. The flare can create some tail lift, which I/we definitely dont need at high speeds. May be worth a mph or so removing it, nothing substantial.

I hope to get a Merc Altitude soon to test and see how it compares. It should be the best of both worlds for an overhub cleaver.

Alright thanks alot for the advice on prop... Will just blueprint without changing the configuration. Tail lift... makes me wonder... The next day after I got my best top speed, went back on the water and the end of the day tought I would give it a small shot just a couple quick 102-105 runs just for fun not trying to break any record. I've waited a little to much before full throttle so I was running out of lenght and I trimmed a little too much to accelerate and didn't backed it down enough. When I dived on the trim found out that the bow was higher than usual but also found out that the RPM was @ 7000 and water pressure was 5 psi. So I thought the whole hull was lifting but I wonder if it's that stern lift that made 7000 and 5 psi or I was simply starting to blow over? Was still 107... Billy described that condition and I think I found that limit also. Something not to repeat too often. When you had too much stern lift did the prop started to slip ?

The Altitude should be a nice prop yes. And available in larger diameter 15.62 so probably something worth trying with the big torquer you got!

Thanks

Jimmy