Skeg Problem

[j_martin]

On my XR4, there's been a notch missing from the skeg since I've owned it, about 3 years. Today, a new notch appeared. I have no idea how it could have happened. I did get into a little mud stirring today, but suffered no noticable prop damage that would corespond with this. The break is very clean, and shows no signs of bending or being struck.

There is a slight bend in the aft edge of the skeg. I assume it's for torque compensation. I wonder if it is stock, or if someone put it in and damaged the metal doing it.

At any rate, what do I need to do about it?

John

[PROGRESSIVEAUTO]

If you remove the lower and are OK with shipping it, I can set you up with a fabricator that replaces skegs daily at quite an affordable cost.
I am guessing possibly that the skeg may have already been repaired previously and the repair or incorrect aluminum has fatigued and is breaking apart. Mud or rock damage would likely show up on the leading edge.

[Raceman]

On surfacing lowers skegs always fail from the rear, so that's a VERY RISKY area to be repairing on. I don't know the nature of your boat/setup, but if it's halfway fast and halfway high, I wouldn't have a skeg repaired in that area on my boat.

As far as what caused it, if it was a damage issue from "mud stirring" I would think it would have to show on the prop, although possibly to some lesser degree. If you don't see any signs of it at all on the blades it might be worthwhile to look closely for signs of previous work.

[olmo40]

both of the above are right also have a look at skeg guard

[j_martin]

On surfacing lowers skegs always fail from the rear, so that's a VERY RISKY area to be repairing on. I don't know the nature of your boat/setup, but if it's halfway fast and halfway high, I wouldn't have a skeg repaired in that area on my boat.

As far as what caused it, if it was a damage issue from "mud stirring" I would think it would have to show on the prop, although possibly to some lesser degree. If you don't see any signs of it at all on the blades it might be worthwhile to look closely for signs of previous work.

Just looked at it again. There is a very small nick in the housing, back edge. There is also a slight roughness to one edge of the prop near the hub. I suppose it is possible I found a stick of scrap metal on the bottom.

More input on this.

1. When I bought the boat, the owner said he bumped the drive with the tip of the skeg and put the lower chip in it. I always wondered about the shape of the chip.

2. The skeg has a bit of a "torque tamer" bend in the rear edge. Is this stock, or did someone do it?

3. The upper damage seems to be along the same imaginary line up the rear edge of the skeg. If it was damaged by bending, that's about where the weakness would be.

I have access, probably free, to metalurgical x-ray. I should be able to find any other hairline cracks in it.

Now the boat is set up so the bone stock engine cooling loses pressure just before max trim at WOT. When I run it there, I have a long low roost, nose is up a few degrees, engine is level, and speed is in the 60's with a fishing load. If it's repairable, maybe I should lower the engine back into the lake, and slow down a bit. If I put the 22 inch screw back on, I should be able to run high 50's at 6000 rpm.

The budget is under stress right now, just like everyone else.

Thanks for the help and advice.
John

[PROGRESSIVEAUTO]

All of the skegs that I have seen are straight. I have seen the torque tabs/plates sold but they are they are usuallt located above the prop or bolted onto the skeg.
I would have that whole skeg cut off and replaced if it were me. If that skeg were to come totally apart on you, you could be in for a wild ride.;)

[j_martin]

When I got this boat, not much of anything was done right. Steering cables had too much bend in them, fuel and tuning was off, wrong prop, wrong engine height. It wouldn't surprise me if the ace (spelled with a double s) put a torque tamer in it with a paddle pliers.

If that's the problem, there'll be x-ray visible hairline cracks along the rear edge. 90 percent of the skeg is good to go. The fix would be to have the prop shop cut the bad metal off, fashion a torque tamer out of repair stock, which is a more maleable aluminum, and tig it on properly. (preheat, 5000 rod, etc) A little metal removal for torque tuning and it should be good to go for another 20 years.

A torque tab doesn't do much when it's running 3 inches out of the water. That's why the trailing edge of the skeg needs attention. The only other way to go straight is to turn right a little and crabwalk.

I trust my prop man more than Mom. If he says he can do it, it's a go. If it's dangerous, he'll say so, and explain why.

Thanks again
John

[mirage243]

John, I can put a skeg on that thing and you'll never know it 's not factory. The shipping would be more than the job though.

[j_martin]

John, I can put a skeg on that thing and you'll never know it 's not factory. The shipping would be more than the job though.

What's yer professional opinion on my plan? I think my man is up to it, or he'll tell me so. He's a top prop man around here. It's hard to tell it ain't new when he's done.

If I get cold feet, I'll put it deeper in the lake and run it slow for now, then see ya, boat and all sometime when it's %*&)(* snowing around here.

For priorities, see my sig.

Thanks
John

[Raceman]

I gotta tell you guys, I REALLY HATE IT when replacing skegs is mentioned here. I think it's ridiculously dangerous and potentially life threatening. It's the reason that repaired skeg gearcases are specifically not allowed to be sold here. Even when someone welds one on a low performance boat, there's always the potential for another owner to later run it on another application and hurt themselves or someone else.

Again, I don't think a damaged/cracked from the rear skeg should EVER be repaired unless it's unable to be used now or later on a upper horsepower engine, (meaning a small engine gearcase type gearcase) and think the suggestion of cutting one off and replacing it completely is VERY POOR advice.

[PROGRESSIVEAUTO]

Yeah, do not take our advice ,what would we know. Stick with Racemans advice. Buy a new gearcase. I am done.

[j_martin]

Would it make any difference if we're talking 70 tops, not 134.6?

I can see a shear off at the gear can being really bad, but if we're working with a fracture line caused by someone bending it with a damned vice grips at the rear edge, and the whole damned thing breaks away, with NFB steering at 70 mph, it'll equal about a 6 degree course change to the left.

Understand, It's going to be x-rayed, both before and after.

Thanks for the advice, honestly. I respect your experience.

John

[Raceman]

John, I've seen a skeg come off on a 120's capable STV that was only running 70's or maybe low 80's at the most, and trust me, it ain't a 6 degree turn. A 180 or 360 bat turn would be more like it. I'd be more inclined to run it as is than to weld on it.

As far as X-raying goes, all that will do is define any defect in the integrity of the weld itself. It won't show compatibility of the metals or changes due to temps during welding. Bare in mind that skegs fail in "as cast" condition, and NOBODY can weld one back to the initial integrity as when new. Some of the experts pre-heat the case to minimize heat related stress when welding, and there are some other processes that I've heard of, but the problem is, you're risking serious injury that a welder can make one ALMOST as good as new. I just value my ass more than that.;)

[j_martin]

John, I've seen a skeg come off on a 120's capable STV that was only running 70's or maybe low 80's at the most, and trust me, it ain't a 6 degree turn. A 180 or 360 bat turn would be more like it. I'd be more inclined to run it as is than to weld on it.

As far as X-raying goes, all that will do is define any defect in the integrity of the weld itself. It won't show compatibility of the metals or changes due to temps during welding. Bare in mind that skegs fail in "as cast" condition, and NOBODY can weld one back to the initial integrity as when new. Some of the experts pre-heat the case to minimize heat related stress when welding, and there are some other processes that I've heard of, but the problem is, you're risking serious injury that a welder can make one ALMOST as good as new. I just value my ass more than that.;)

X-ray will show cracks that are internal, and not even to the surface. It'll also show hydrogen inclusions and other defects in the original cast. If there's any weakness anywhere in the top half where it might detach a large area suddenly, it goes in the scrap bin. If it's the beginning of a catastrophic failure, it'll show up in those areas.

Ain't no way I'd cut and weld a whole skeg, or try to repair one that's been bent to failure, or even bent for that matter. This thing has a problem in the trailing edge, and has had some paint rubbed off. It seems strait and sound otherwise.

I didn't figure the 6 degree turn on the whole skeg leaving, just the "torque tamer" structure in the aft edge.

Thanks again
John

[john ring]

if you are going to continue running it,if it were mine i would take a dremel tool and smooth out all the broken edges,it may prevent further cracking by getting rid of the stress risers,imo for what its worth

[j_martin]

if you are going to continue running it,if it were mine i would take a dremel tool and smooth out all the broken edges,it may prevent further cracking by getting rid of the stress risers,imo for what its worth

Thanks, didn't think of that.

John

[TEXAS20225]

is factory on later models of xr6 small case im not sure on the xr4 also comes on late model hipo cases if it were my case id weld it up and never think on it again! Ever