Hooked Hull

[Pa Angler]

I thought I had engine problems with all the smoking and loss of top end mph I went from 60+ mph to mid 40 mph and the smoking motor was the cause I have been notified by my Nitro dealer that my 2011 Z7 has a hooked hull and the boat is being replaced by Nitro I was also told that Nitro wants my boat back fast as Nitro wants to tear it apart and find what went wrong it's the first one that wound up with a hooked hull sold at my dealer.

 

I didn't know anything about a hooked hull until now I was shown what to look for as I can see a section of the hull not making contact with the bunks all the way across the hull from port to starboard  in front of the transom.

 

Has anyone ever had this issue?

 

Tight Lines

Pa Angler

[martintheduck]

So - You get a brand new boat out of the deal... That's awesome! Could have gotten stuck with the "can't help you...." It'd be cool if you could take pictures of it somehow and show us what this "hooked hull" looks like!

[tomustang]

Haven't heard about it. Good to hear the matter is being taken care of, what are they going to replace it with?

[Pa Angler]

Haven't heard about it. Good to hear the matter is being taken care of, what are they going to replace it with?

 

A new 2013 or 2014 Z7 which ever is in stock of my color combo. It's just the boat my motor and extras get transfered over to the new boat.

 

Tight Lines

Pa Angler

[Sam]

Glad to hear BPS and Nitro are standing behind their product.

 

Very interested in what happened during the manufacturing process to cause the problem.

 

Will never get a Nitro as the Richmond, VA BPS Power Pros are terrible but it is interesting to read about your hooked hull.

 

Please post a pic if you can and glad everything worked out for you.

 

And good luck with your Nitro Power Pros service. You may need it.

[slonezp]

At least it's happening at the end of the season instead of the beginning.

[awefvawervwae]

never heard of it till now. Glad its getting taken care of. LIke others say pictures if possible would be great so we can see what it looks like.

 

I have to agree with Sam, the Richmond BPS is horrible. Only reason why I go to it is if I have to be over that way for work and its only to browse the fishing section.

[Pa Angler]

I didn't purchase the Z7 at BPS I purchased mine at a stand alone dealership which is why I may be getting the results that I am.

 

Tight Lines

Pa Angler

[J Francho]

What is a "hooked hull"?  Pics?

[slonezp]

What is a "hooked hull"?  Pics?

I don't know either, but this is the second one I've heard of in as many weeks. The other one is on a Charger.

[MacP]

[J Francho]

The only way I could see that happening is if a stringer came loose, and even then, I'd think the hull or top cap would crack.

[retiredbosn]

From looking online the two main causes are poor quality and the transom ends up being lower that the hull, or storing the boat with having the transom unsupported

[BKeith]

A hooked hull can be caused by a number of problems. One of the main causes is not sitting on the bunks properly. Then you can have a manufacturing defect, where the hull was not properly supported or the mold was bad, and developed a hook. Since this is a 2011 hull, one would think it's not a mold problem if this is the first one Nitro has had, or could just be the one that has shown up first, and once they check yours, they may send out a bulletin to have all the hulls that were popped from that mold checked. I remember back when Stratos replaced a bunch of hulls on one of their boats because they would do a Bat turn for no real reason when up and flying on the pad.

Then you have boats that have a hook built in to help performance. Allison is one, if you take the hook out of some Allison hulls, you will ruin it. However, a hook in a hull that's not suppose to have one, is never a good thing. That's why I always blueprint my hulls with a lot of body filler and sand my hulls with 320 grit. Makes them flat and smooth so they slide across the water nice and FAST.

[Brian Needham]

so what does "not sitting on the bunks properly" actually mean?

 

too far on the bunk? not enough? misaligned?

[tnriverluver]

Pretty hard to imagine a fiberglass bass boat hull getting a hook from the trailer bunks being out of whack.  Happens quite often with aluminum boats if the transom overhangs the bunks too far but a glass boat would almost certainly be a manufacturer defect or broken stringer.  I very large cruiser that weighs many thousands of pounds yes, but not a 1-2 thousand lb boat.  Glad to hear Tracker is stepping up to the plate and correcting this for you.

[retiredbosn]

The boat's transom should be fully on the bunks.

[Pa Angler]

A hooked hull can be caused by a number of problems. One of the main causes is not sitting on the bunks properly. Then you can have a manufacturing defect, where the hull was not properly supported or the mold was bad, and developed a hook. Since this is a 2011 hull, one would think it's not a mold problem if this is the first one Nitro has had, or could just be the one that has shown up first, and once they check yours, they may send out a bulletin to have all the hulls that were popped from that mold checked. I remember back when Stratos replaced a bunch of hulls on one of their boats because they would do a Bat turn for no real reason when up and flying on the pad.

Then you have boats that have a hook built in to help performance. Allison is one, if you take the hook out of some Allison hulls, you will ruin it. However, a hook in a hull that's not suppose to have one, is never a good thing. That's why I always blueprint my hulls with a lot of body filler and sand my hulls with 320 grit. Makes them flat and smooth so they slide across the water nice and FAST.

This all true as I have done some research online however I can rule out rest on the bunks wrong as Tracker builds the trailer to the model the Z7 centers itself as I found through loading it. The sales manager thinks it's due from shrinking fiberglass Tracker wants this boat back fast makes me think that there's an issue with the laying of fiberglass, resin and maybe the mold this started in August of  2012 when I lost 10 mph and continued to get worse now 15 mph to 17 mph loss the manager thinks that the hull is in a constant state of shrinking and will continue to do so. I have had the boat back more than enough times before a hooked hull was looked into.

 

Tight Lines

Pa Angler

[Fishing Rhino]

The boat's transom should be fully on the bunks.

 

Not possible with a stepped hull.  But the knees or other transom supports should extend onto the step so the transom is properly supported. 

 

 

It is not evident because of the angle of the photo, but the transom is a foot behind the step, and the bunks end at the step.

 

Whether a boat has bunks or rollers, they should be placed so the weight of the boat is carried by the stringers or frames/bulkheads of the boat.  If the weight is borne by a different area, the hull will deform.  Since almost any material used in building boats has a "memory", over time, that depression will not spring back.  Even if it does, the area will tend to deform when the pressure of the water acts upon it, forming a hook when underway.

[Pa Angler]

Not possible with a stepped hull.  But the knees or other transom supports should extend onto the step so the transom is properly supported. 

 

 

It is not evident because of the angle of the photo, but the transom is a foot behind the step, and the bunks end at the step.

 

Whether a boat has bunks or rollers, they should be placed so the weight of the boat is carried by the stringers or frames/bulkheads of the boat.  If the weight is borne by a different area, the hull will deform.  Since almost any material used in building boats has a "memory", over time, that depression will not spring back.  Even if it does, the area will tend to deform when the pressure of the water acts upon it, forming a hook when underway.

That'a a good pic of Nitro's RPS as you can see the drain plug is centered inline with the rear roller and the bottom were the boat sits on the bunk is stepped so it would be highly unlikely that a Nitro Z7, 8 or 9 won't center it's self. Color of transome area looks like Nightfire my Z7 color combo is PR56A.

 

Thanks for the pic.

Pa Angler

[Pa Angler]

This is an excellent illustration of what a hook is and this is what my hull looks like on the bunks front and rear of the hook is sitting on the bunks and the middle off the bunks. Thank You for the illustration.

 

Tight Lines

Pa Angler

[Fishing Rhino]

That'a a good pic of Nitro's RPS as you can see the drain plug is centered inline with the rear roller and the bottom were the boat sits on the bunk is stepped so it would be highly unlikely that a Nitro Z7, 8 or 9 won't center it's self. Color of transome area looks like Nightfire my Z7 color combo is PR56A.

 

Thanks for the pic.

Pa Angler

 

The boat in the photo is a pre RPS hull.  The main difference between the older hull and the RPS hull is the distance between the step and the transom.  The step is much longer on the Z7 pre RPS.  Probably twice as long.  By shortening that distance, it puts the lift at the back edge of the step closer to the transom, reducing the leverage of the mass of the motor, allowing the hull to lift much faster at the rear. 

 

The Z-7 in the photo took much longer to get on plane than my Z-8 with the rapid planing system. 

 

A helpful hint for those whose boats struggle to get on plane at times.  Steer the motor to the left or right when taking off.  By pushing the stern to the left or right on takeoff provides more lift for the stern since you are using the lift afforded by the angle of the v bottom.  When the rear starts to lift, you can steer a bit in the opposite direction to get on plane even faster.

 

With a little practice you'll learn how much steering input is optimum for getting on plane faster, and the best tempo for steering slightly back and forth.

[Pa Angler]

The boat in the photo is a pre RPS hull.  The main difference between the older hull and the RPS hull is the distance between the step and the transom.  The step is much longer on the Z7 pre RPS.  Probably twice as long.  By shortening that distance, it puts the lift at the back edge of the step closer to the transom, reducing the leverage of the mass of the motor, allowing the hull to lift much faster at the rear. 

 

The Z-7 in the photo took much longer to get on plane than my Z-8 with the rapid planing system. 

 

A helpful hint for those whose boats struggle to get on plane at times.  Steer the motor to the left or right when taking off.  By pushing the stern to the left or right on takeoff provides more lift for the stern since you are using the lift afforded by the angle of the v bottom.  When the rear starts to lift, you can steer a bit in the opposite direction to get on plane even faster.

 

With a little practice you'll learn how much steering input is optimum for getting on plane faster, and the best tempo for steering slightly back and forth.

OOOPS, I guess I didn't take a close enough as the tunnel I have at the transome is missing but the way mine sits on the bunk it looks a lot like yours. What year was it?

 

Tight Lines

Pa Angler

[FD.]

Good tip Tom.  My Triton does better with a slow right turn.  If I go left I get cavitation from the leading edge of the prop being in disturbed water.  

[Fishing Rhino]

 

OOOPS, I guess I didn't take a close enough as the tunnel I have at the transome is missing but the way mine sits on the bunk it looks a lot like yours. What year was it?

 

Tight Lines

Pa Angler

 

 

It is a 2009.  The RPS was introduced in 2010.