My prop blast is eating my gelcoat!

[TallRedRider]

So I just bought a new to me 2006 X-45.

I thought I gave her a pretty decent shakedown at the dealer who is 300 miles away. I was at a family activity that required me to be in best dress immediately before we went to the dealership, so I was did not actually lay on my back under the boat. I did the usual, inspect the prop and rudder for damage and the shaft...all looked good and I bought the boat.

Then after I got home, I found this:




There is a small section of the hull behind the rudder that is at a slant. You don't see this if you kneel under the swimstep and grab the rudder because it is slanted and faces forward a little. The gelcoat was ragged and looked eaten away. Bare shards of fiberglass are bulging from within.

I shot an email to my salesman and his first impression was the same as mine..'WTH?'

He showed my pics to the head tech at the shop who noted that it is due to prop blast going past the rudder and then wearing away the gelcoat and that it happens often enough that MC has now placed a steel plate over the rudder plate to protect that area from the turbulence from the prop.

Sounds sort of crazy to me, but he then crawled underneath an 09 X-45 and indeed there is a plate there that shields that part of the hull from the prop blast.

Here are the cell phone pics he sent me of an 09 with the plate. They look a little funny because the hull is black, so it takes a few seconds to orient yourself.

So the message is to take a look at your hull right there and make sure it is holding up fine.

The guys at Utah Water sports agreed to put a plate on my boat for free. Definite standup guys who are working at giving awesome customer service.

[Gamble]

that's interesting.......I believe my ol stars and stripes had those exact same marks yours does. Now I know what caused it!

[Witness140]

Did they indicate this is an issue with all of the boats - or just the 45? I'm looking at some pics of the bottom of an 09' X2, and it doesn't have that plate.

[TallRedRider]

They did not indicate if this is specific to the 45. I suspect that any of the boats that have a recessed rudder plate and then have a slanting gelcoat 'box' if you will, would be at risk.

[coz]

I think this needs further investigation, prop wash eating the fiberglass? If that's the case there will be others. I'll bet hundreds of MC owners will be looking under the boat after seeing this post for holes like I just did, I'm good.

Keep us posted this is interesting. To me it looks like a rock chip that maybe was helped by the force of the wash after there was a hole started.

Good luck!

[SaltwaterMC]

Do you have the 8.1L in your 45? From what I understand, they only put the plate on the 45s with the big block because apparently that engine in that boat can create cavitation which can cause gel damage.

[bigmac]

Originally Posted by coz

I think this needs further investigation, prop wash eating the fiberglass? If that's the case there will be others. I'll bet hundreds of MC owners will be looking under the boat after seeing this post for holes like I just did, I'm good.

Keep us posted this is interesting. To me it looks like a rock chip that maybe was helped by the force of the wash after there was a hole started.

Good luck!

Agreed. That looks like foreign object damage to me. Not only the gel coat, but the underlying fiberglass too. All looks disrupted, as from impact.

[prostar205]

Originally Posted by Go Red

So I just bought a new to me 2006 X-45.

I thought I gave her a pretty decent shakedown at the dealer who is 300 miles away. I was at a family activity that required me to be in best dress immediately before we went to the dealership, so I was did not actually lay on my back under the boat. I did the usual, inspect the prop and rudder for damage and the shaft...all looked good and I bought the boat.

Then after I got home, I found this:




There is a small section of the hull behind the rudder that is at a slant. You don't see this if you kneel under the swimstep and grab the rudder because it is slanted and faces forward a little. The gelcoat was ragged and looked eaten away. Bare shards of fiberglass are bulging from within.

I shot an email to my salesman and his first impression was the same as mine..'WTH?'

He showed my pics to the head tech at the shop who noted that it is due to prop blast going past the rudder and then wearing away the gelcoat and that it happens often enough that MC has now placed a steel plate over the rudder plate to protect that area from the turbulence from the prop.

Sounds sort of crazy to me, but he then crawled underneath an 09 X-45 and indeed there is a plate there that shields that part of the hull from the prop blast.

Here are the cell phone pics he sent me of an 09 with the plate. They look a little funny because the hull is black, so it takes a few seconds to orient yourself.

So the message is to take a look at your hull right there and make sure it is holding up fine.

The guys at Utah Water sports agreed to put a plate on my boat for free. Definite standup guys who are working at giving awesome customer service.

Go Red (Tall) -

I had almost the same issue with my '02 X30 a few years ago. My dealer started picking at the gel coat around the rudder area because I noticed some cracking in the gel coat. It turned out to be voids (air pockets) in the fiberglass. They drilled it all out and filled back in with fiberglass and new gel coat. You can't even tell them worked in that area. I would definately have UWS repair the gel coat becuase you don't just want to put a plate over exposed raw fiberglass. Water will still get in there and weaken the structure of the rudder area. After the gel coat has been repaired correctly, then put the plate on it.

By the way, my boat has the L-18 motor in it so there may be some truth to it only happening with the big block boats. I will post pictures (I have a ton) of this repair when I to work on Monday.

[bturner2]

I'm going to lean towards cavitation on this one. I've seen SS props eaten up by cavitation so some soft fiberglass would be a quick victim if in the path of some boiling water off a spinning prop. Combine that with some hard take offs in shallow water and you get a hole in the unprotected area of the hull.

[TallRedRider]

Originally Posted by SaltwaterMC

Do you have the 8.1L in your 45? From what I understand, they only put the plate on the 45s with the big block because apparently that engine in that boat can create cavitation which can cause gel damage.

Yes, it has the 8.1L engine.

Originally Posted by prostar205

Go Red (Tall) -

I had almost the same issue with my '02 X30 a few years ago. My dealer started picking at the gel coat around the rudder area because I noticed some cracking in the gel coat. It turned out to be voids (air pockets) in the fiberglass. They drilled it all out and filled back in with fiberglass and new gel coat. You can't even tell them worked in that area. I would definately have UWS repair the gel coat becuase you don't just want to put a plate over exposed raw fiberglass. Water will still get in there and weaken the structure of the rudder area. After the gel coat has been repaired correctly, then put the plate on it.

By the way, my boat has the L-18 motor in it so there may be some truth to it only happening with the big block boats. I will post pictures (I have a ton) of this repair when I to work on Monday.

The interesting thing about the rock chip theory is that the damage is exactly behind the rudder and it is going to be a challenge to figure how a rock gets from the prop then swirls around the rudder and hits the glass with enough force to cause the damage. I guess that could happen.

UWS said that they would fix the fiberglass for me, if I wanted, but that it was not necessary because the plate they put on is sealed with sealant, and would stay dry. Frankly, I don't have much faith in that, so I slapped some gelcoat on there yesterday. We'll see if that holds until I can get her up there. It does not need to look factory once it is covered with the plate, but I agree it should be water proof, even if the plate is sealed.

Wouldn't surprise me if the previous owner did hard starts in very shallow water, as that it appears that he beached the boat on the rocks as well. I have some gnarly scratches on the keel. Gel coat is surprisingly cheap to fix by those who know what they are doing. And it is undetectable when done right.