Weierd boat attitude at WOT

[1FASTLASER]

I know its a smaller boat but u guys are the experts..Its a Tidecraft 16ftr with a slightly warmed up 90 Evinrude sittin on a CMC 5.5 jack. Running a 13x20 Raker. Here's the deal....get her up and running start approaching topend speed but the hull still hasn't jumped on pad....now I am on the gas...wide open at this time.....to get her to jump up on the pad and really starrt to fly the hull I have to bump the throttle back maybe a 1/4 and wolla...she jumps on pad like a well trained dog....thing is I still have trimm left and throttle but if I apply either the hull drops off pad and by dropping off I mean only the back end sets back down.....What could possibly cause this. I know I have more topend left but can't get there because of this.

[200VEGAS]

sounds like ventilation. could the hub be slipping, cause the raker has good grip and shouldnt ventilate

[1FASTLASER]

I am positive that the hub isn't slipping. Scribed makes are still perfectly inline. I am really stumped with this one.

[Carter Powell]

Does the RPM decrease when you cut back on the throttle or stay the same. The prop may be losing it's bite and starting to slip somewhat which cuts down on forward thrust. This would lead to a slight loss in forward motion which could contribute to it falling off the pad. Can you try another prop which is somewhat similiar. Try to give a little more information on speed, RPM, etc, when this happens.

Carter Powell

[1FASTLASER]

It will happen at any speed over say 35 or so. I bump the throttle back a little and rpms drop but speed will usually increase 2 maybe 3 mph when it jumps on pad. But like I said I try to increase speed and she falls of the pad. Doesn't matter what way I try to increase....slow fast....just bump the trim....it don't matter its going to do it. Thing is I know for certain if I could keep her on pad then I could definitely gain on the top end due to the leads wetted surface....maybe the prop is that out of wack???....it does only due it with my taker prop. My sst it won't do it. I am trying to get a sex as we speak to see if it does the same . Thanks Ford anything you can help me with Mr Powell. Also do you think maybe I need more cupping on the raker??

[Carter Powell]

Here are a few things we need to know first. Do you have a tach and if so what RPM is the motor turning. Please take some pictures of the back of the boat, the prop, etc and post them for us to look at . It will really help. From what you are describing I am going to bet on prop slippage with that prop. You really need to try some other props to get a better feel for this. Pictures really would help.

Best wishes, Carter

[200VEGAS]

take some pics of the transom area. how high is the motor. do you run a nosecone

[transomstand]

By your description, the boat sounds like it's acting "normal". Keep in mind that application of forward thrust will also tend to push the bow down.

Many boats, when you back off from wide open, will get "light", or "float", because of the reduction of thrust.

There are several things that can be changed, but I would think the most helpful would be a prop that "carries" the hull better, with more bow lift.

Right now, the prop can't overcome engine thrust, and increasing trim just drives the back of the boat deeper into the water.

[perfmarine1]

You may also want to check and make sure the carb butterflys are not opening past full wide open,you may need to adjust WOT stop.

[inspectorlance]

Is this Tidecraft 16, the one that is a splash of the Hydrostream viper hull with a bass deck? if so, that may help others give info. Lance

[1FASTLASER]

Inspector lance you are correct.......i bought this boat because of this. I can't say with a 100percent amount of accuracy that it is. The hull is a 1994 model äs well as the engine is. In complete stck form she has been quick and very agile. I do wish there was a way to confirm that this is the splashed hull. Anyways this weekend I will snapp a photo or 2 and maybe this will help. Carter Powell my tach quit before I started trying to figure out what is goin on....i will fix and report back with correct numbers...and to let all know any speed I post is from 2 GPS units...one installed in the boat and a handheld. Inspector I will say that this boat acts like any hydrostream I have ever rode in......very weight sensitive forward to rear and side to side.

[inspectorlance]

1fastlaser, I have a Skeeter Wranger bass boat project, and when asking questions and reading, I was informed that the Skeeter wrangler , glasstream, and I think the Tidecraft were a splash of the viper. Of course each company makes some small changes to say its thier design.This splashing was done back in the 70's and early 80's when the Viper was king. Skeeter even had a 15' called the Odessey that was identical to the viper deck and all. I only mention the possible Viper connection because it may help others point you in the right direction. No hard evidence of the splashing, just what the old timers say, that where around back then. Even my STV flys higher when I back off the throttle slightly.

[1FASTLASER]

Had a buddy that had a skeeterr wrangler with 140 rude. This was kinda about the time I really started getting in to boats. What's blast that water sled was. Fantastic holeshot and would give most 150 and 175 boats a fit. Anyways back on topic. Knowing that more boats than just mine does that.....this is the only boat that I remember does that that I have had.....is this action or happening....is it not evidence that there is something quite not right. I do understand now just because I didn't think about the forward thrust and the fact that the engine and trim angle...when I nail the throttle again drives the nose back down. I guess I could infact be barking up the wrong tree.

[steve@scp]

i've run into that ALOT with rakers. mostly on ranger boats. nothing wrong with boat or engine or anything else.
you just need to send your raker to your prop guy to have the cup wrapped around the tips. the water is flying off the tips making the prop loose it's bite.
easy fix!

[transomstand]

i've run into that ALOT with rakers. mostly on ranger boats. nothing wrong with boat or engine or anything else.
you just need to send your raker to your prop guy to have the cup wrapped around the tips. the water is flying off the tips making the prop loose it's bite.
easy fix!

:iagree:

A little cup in the tips may be all it needs.

[afr]

sounds like the angle of attack on the motor is just a touch positive to me in other words the bow angle needs to drop a degree or so to kick it up on the pad hence backing off the gas it jumps right up on the pad

I know its a smaller boat but u guys are the experts..Its a Tidecraft 16ftr with a slightly warmed up 90 Evinrude sittin on a CMC 5.5 jack. Running a 13x20 Raker. Here's the deal....get her up and running start approaching topend speed but the hull still hasn't jumped on pad....now I am on the gas...wide open at this time.....to get her to jump up on the pad and really starrt to fly the hull I have to bump the throttle back maybe a 1/4 and wolla...she jumps on pad like a well trained dog....thing is I still have trimm left and throttle but if I apply either the hull drops off pad and by dropping off I mean only the back end sets back down.....What could possibly cause this. I know I have more topend left but can't get there because of this.

[1FASTLASER]

Ok went back and went through everything with a fine tooth comb. Here we go....carb butterfly perfectly level when at WOT....3 1/4" below pad.....still have 14lbs water pressure...on a side note in the future raising the motor. Anyways I was going over my original speed and rpm numbers when the dang tach took a crap on me....checked everything....power,ground and signal ...all is good have a new tach on the way. I don't remember what is the pole setting for a v4 rude? Just before tach took a crap GPS speeds was 51.6...tach was at 5750.....just bumped the throttle back speed remained the same ...boat jumped on pad and the tach crapped on me. So long story short will report back on tach numbers after new tach. From just listening it sounded and appeared to me that rpms actually dropped.

[1FASTLASER]

Ok folks due to work schedule being really messed up latley I havent fixed my tack yet but I did in fact borrow a buddies of mine prop....and wholla boat was a different critter. Hit the throttle jumped on pad and started trimming up and she actually did in fact climb all the way onto pad and HELD IT. I ran several passes to make sure it wasnt a fluke but didnt push her to the limit simply becasue I dont have the tach problem fixed yet but it seems as though the problem does in fact come down to my prop. So it looks like my prop guy has got some work to do as soon as christmas is over. I will report back once again as soon as I get my prop worked on and the tach problem fixed.
Thanks for everyones help so far with this issue. This is the reason why scream and fly is number one in my book.

[transomstand]

Good to hear ya got it figured out. Sometimes it's just amazing what a prop change will do:thumbsup:

[200VEGAS]

amen, ya did it. feels good to find somthin wrong...

[steve@scp]

:) i figured that's all it was.

just had a guy with same problem.. (another one) fixed his problem in 20 minutes. No more weird acting boat!!
cupping is an amazing thing!