bow rise dilemma

[cocacola]

I am gonna swap out my current 22" prop for a more skiable 19". I figure that will drastically help holeshot and keep bow rise down. Too many heavy people with me when skiing. Since boat has trim tabs on the transom where tunnels are, I thought about adjusting them down about 1/4"-1/2" to help keep bow down too. What about relocating batteries to bow? Probably won't do that. A fella on this forum said his offset engine mount grabs water and had some good suggestions I havent' tried yet.

[pyro]

A skid plate under the jackplate to help keep it from bucketing water, might help.

A typical whale-tail foil will make the biggest difference.

[cocacola]

Forgot to mention that.... Thanks Pryo.

From what I can tell, the skid plate won't be necessary if I have the hydrofoil and it will work longer until the boat gets on plane and it's out of the water too. Engine is at lowest position possible.



A skid plate under the jackplate to help keep it from bucketing water, might help.

A typical whale-tail foil will make the biggest difference.

[Rusrog]

Allison ET Tail. Glenn Reynlods has one one his website. IT's $110.00 but it works like a champ to keep the bow down and pick the tail up.

http://www.reynoldsracingmarine.com/rrstoref2.htm

Give it a look...

[cocacola]

damn that thing is huge

any pics of one installed?


Allison ET Tail. Glenn Reynlods has one one his website. IT's $110.00 but it works like a champ to keep the bow down and pick the tail up.

http://www.reynoldsracingmarine.com/rrstoref2.htm

Give it a look...

[Rusrog]

it really is. I had one but but I don't have any pics of it installed. In all reality it extends back to the trailing edge of the staock cavitation plate and extends to each side by about 4 inches. The pic is way out of kilter. I just went and looked at the pic and thought I was drunk. But then I remembered... I never drink at work on Tuesdays.

[cocacola]

Funny.... they use to actually drink here in the "good ole days". If you happen to get a pic, it would be great. Trailing edge.... is that the part near the prop or nosecose? Seems to me that something this big would eliminated the skid plate idea. On another post, a S&F member says he uses his wife's volleyballs. Good idea as I have many of those.

I want a hydrofoil




it really is. I had one but but I don't have any pics of it installed. In all reality it extends back to the trailing edge of the staock cavitation plate and extends to each side by about 4 inches. The pic is way out of kilter. I just went and looked at the pic and thought I was drunk. But then I remembered... I never drink at work on Tuesdays.

[pyro]

Link to the frame with the ET foil: http://www.reynoldsracingmarine.com/safety.htm

[cocacola]

I didn't understand the pic at first. Looks like this plate extends towards transom and not away from boat. Am I looking at this right?



Link to the frame with the ET foil: http://www.reynoldsracingmarine.com/safety.htm

[Rusrog]

I didn't understand the pic at first. Looks like this plate extends towards transom and not away from boat. Am I looking at this right?

It looks like this one...

http://allisonowners.com/hydro/Dsc01466.jpg

[300x Stoker]

If they put enough transom angle on the boat in the first place you wouldn't need a bandaid like that. There is more than enough positive trim potential on these motors to deal with some extra tuck under by using wedges or a redoing the set back bracket. Some people think it's cool to have the bow fly up and do a wheelie on the holeshot. If you want to do family boating stuff it' a PITA. I like a flat take off and no porpoise at 25mph. Different strokes for different folks. :confused:

One of our beach members had 2 boats just like yours and the first thing we did was put some wedges on the thing.

[150aintenuff]

titus grisham does a cavitation plate mod that works wonders for that as well... and only adds about 1.5" per side so it looks almost stock..... and only costs 125.00 and its permanant

http://www.low-h2o.com/images/Mercury/800s/merc6.jpg

[cocacola]

now this all makes sense Russ. I like how the wide portion is not aft like Stingray's. Closer to the transom should put less stress on all parts.

Stoker... I am with you. Even when riding alone, I cannot see the fun in doing a wheelie. Sure as hell isn't getting you moving forward any faster. Now I have hit the throttle hard while trimming up....Save the trim for running speeds, not holeshots.

Interesting "150.....". Seems like a good idea like built in low water pickup and torque tabs. Not add on's.




It looks like this one...

http://allisonowners.com/hydro/Dsc01466.jpg

[pyro]

Those of us with fishing motor trim can tuck under as much as we want, but then we can't trim up fast enough to get itfully aired out in the short track!

[150aintenuff]

Interesting "150.....". Seems like a good idea like built in low water pickup and torque tabs. Not add on's.

I love mine....

[Rusrog]

stuff. I had him do a Nose Cone for me and it has made a noticable difference in how well my Allison drives. I didn't have him do the cav plate mod as I knew I was going to be making changes and wanted the flexibility.

The Allison plate is generally regarded as a very good aid in planing and for the types of boating that a lot of us do... It is the best deal going. You can move it a bit forward or a bit back and it bolts on with a minimum of effort, with the gearcase attached.

Russ

[RIVERRUMMER 70]

Those of us with fishing motor trim can tuck under as much as we want, but then we can't trim up fast enough to get itfully aired out in the short track!

THIS IS WHAT 24V TRIM IS FOR!

[150aintenuff]

extra weight..... 2 batteries suck.... thats 50-80 more lbs ya have to try to fly... i set my motor level and with titus,s case and a small prop it jumps out.... with the big prop it rises a bit.... but NOT MUCH... to do a good wheelie i have to be full trim and bump the throttle 2 or 3 times.... then she comes up hard... other wise its a good flat launch... especially woth all my weight stern...

[captcarb]

The whale tail and all of those foils will put rollers in the wake that the skiers may not like.

A wedge and a non bow lifting prop will work much better. Or, modify the set back to give more tuck if you like.

jim

[Techno]

Why can't you just run in negative trim to keep the bow down? Isn't it enough?

[cocacola]

Yesterday, I tried a 20" HighFive. It had small holes in hub, but not large like some PVS versions. It cavitated like hell on launch, but when it bit hard, we took off strong. I want to try with hydrofoil. Looks like I have found an Allison hydrofoil for a good price. Engine has one more set of holes to lower and possibly get more bite, but I think this prop is not right for this hull. Cannot imagine how lower pitch props would have worked (cavitated). Engine rev'd hard like my old 115...which is what I wanted when pulling up skier.

Not sure how flat this "family Mod-VP" is capable of launching. Bow rise was terrible on launch.

Engine is trimmed/tucked under all the way.

[captcarb]

I'm sorry, but you confuse the hell out of me. You are using a bow lifting prop and complaining about bow rise??????????????

You need more tuck too, sorry again. You need less pitch, really sorry!!

Out.

jim

[cocacola]

sorry? This was my decision. Are HighFives bow lifting props? If so, I didn't know. Thank God it's a loaner. It's tucked in all the way. The education continues.....

What is a good skiing prop that limits bow rise and gives a good hole shot?

Remember... I ski heavy (lots of stuff and people at times)




I'm sorry, but you confuse the hell out of me. You are using a bow lifting prop and complaining about bow rise??????????????

You need more tuck too, sorry again. You need less pitch, really sorry!!

Out.

jim

[captcarb]

The Mercury marine web site has a description of all their props. They labeled the high five as a bow lifting prop, not me.

Their site also has a section on prop theory which is very good reading. I suggest that you investigate that area of their site and also check out the description of all their props. In the prop theory area read about rake and tip cup, that is what you want to stay away from. Look at the Mirage and Vengeance prop descriptions. My opinion is that the Mirage will have too much blade area for your motor. I have no experience with the Vengeance, but it looks similar to older designs that did work well. Remember that heavy loads and skiing require a prop that will not give much top end. It's OK with me if you own more than one prop.

As far as tuck, you can get more with a wedge or by modifying your jack plate. In situations where the extra tuck is not desirable, just trim it out a little. I posted a picture of a 20 foot Hydrodyne club ski boat in another area. It has 3 300xs motors on it and runs 15 inch pitch props.

jim

[cocacola]

I'll visit that site...I am prop stupid. I really didn't want to try the 20", but it was all they had in the HighFive and it was ventilated. Not sure who, but others said I should go with a 17. I was leaning towards a 19. The rpms surprised me with the 20 HighFive.



The Mercury marine web site has a description of all their props. They labeled the high five as a bow lifting prop, not me.

Their site also has a section on prop theory which is very good reading. I suggest that you investigate that area of their site and also check out the description of all their props. In the prop theory area read about rake and tip cup, that is what you want to stay away from. Look at the Mirage and Vengeance prop descriptions. My opinion is that the Mirage will have too much blade area for your motor. I have no experience with the Vengeance, but it looks similar to older designs that did work well. Remember that heavy loads and skiing require a prop that will not give much top end. It's OK with me if you own more than one prop.

As far as tuck, you can get more with a wedge or by modifying your jack plate. In situations where the extra tuck is not desirable, just trim it out a little. I posted a picture of a 20 foot Hydrodyne club ski boat in another area. It has 3 300xs motors on it and runs 15 inch pitch props.

jim

[captcarb]

The high five may not have enough blade area for your motor. The ventilation made it worse and it acted like a blender. I would not base your pitch choice on that test.

jim

[cocacola]

thanks Jim. I went to the site you suggested. Unfortunately, my style of hull is never mention (Mod-VP). My selection from choices wound up being "fish & ski". All the suggested props were all 23P and boasted of bow lift, not stern.





The high five may not have enough blade area for your motor. The ventilation made it worse and it acted like a blender. I would not base your pitch choice on that test.

jim

[300x Stoker]

Of all the props we tested for ski use the Bravo 1 was the best. You might want a 19" or smaller. It seemed to lift the whole boat evenly and was superior to the others we tried at low speeds. YMMV but try to find one in a low pitch to demo.

[captcarb]

What motor were you testing on?

jim

[300x Stoker]

300X.


What motor were you testing on?

jim

[captcarb]

He has a 2.5. I think that prop might have too much blade area for the small block.

jim

[300x Stoker]

The big motors have more low end. If he could find one to try for free it couldn't hurt.

[cocacola]

I'll "rent" a Bravo one if a small one is available.

Also asking the Prop Hottie for her advice....yep, our local prop shop has a woman running the show. She's on ESPN radio on Saturday mornings. Unfortunately for Hot Boaters like us, they don't know what a Mod-VP is.

thanks