stv pro comp stress cracks

[cptunnel]

Ok, so i have a '92 model pro comp ski and is in great shape super clean and solid as a rock all the way thru inside and out and all around but has stress cracks by the hump where it goes up to the top just in front of the back seat and cowling..they have been there since i got the boat but seem to have gotten worse when someone has been in the back seat in choppy water..i have seen a few others with stress cracks here but on one side it is cracking all the way thru..this drives me crazy..i imagine it is from people riding in the back seat when i dont have the light weight race cowl in since it is supported on the sides..question is, is this normal, and is it repairable? and if so who or what do you recommend? and help/advice/experience with this would be appreciated..see pics

[baja200merk]

They can be fixed. You have to make sure the seat is glassed to the hull or it will happen again.

[cptunnel]

So if I do that I cant open the cowl? Sorry I'm not understanding. And apparently it has happened to others than me? Thanks for the insight

[petehubbell]

I no longer have the back seat for my STV but it also had a few very small cracks in that area. If I were you I'd try to insure that you had something under the seat that carries the weight to the floor of the boat in order to minimize the load on the sides where the cracks are. The glass under the cracks will have to be reinforced and possibly some structure added to stiffen the area before any repair is done. It can be fixed. PH

[STV_Keith]

My PCS had the same cracks. When I bought it, they were small, like stress cracks, but one wave taken at an angle (quartered it) caused the boat to flex and twist and caused a major rupture. When the front of the port sponson hit the wake first, the boat twisted lengthwise and I heard a snap.

That "saddle" in the deck is the weakest part of the boat, so therefore what is going to flex and crack. Once you fix that, flexing may happen at the next weakest spot and other cracks may appear. On my boat, where the fuel fill was drilled through the side of the deck about 1/2 way between the rear seat and the transom now has a crack from the hole up and over the deck. I've put a fill opening directly in the tank, so I'll be glassing that hole up completely soon.

When my glass guy turned the boat upside down to get in there, it had been repaired before. He went in from the top and bottom and ground the area out and reglassed it. That was almost 10 years ago. They are beginning again in that area, but due to the water I run in, that's just a part of life. This winter it's going back for a 15" transom and a few other upgrades/repairs, so we'll look into it again.

[cptunnel]

OK thanks for the feedback guys..I'm glad to hear its not the first to do this..I plan on fixing it soon and will reenforce that area along with making sure the bottom of the seat is supported by the floor..thanks again guys!

[kellytheaker]

So can there be further discussion on this subject .92 super comp is the hull and deck of "somerfeld" is that correct and was the newer Triad hull an improved bracing /kneewall ,in the structure .
And the reason for the subject to be brought forward is this is now almost 2018 and they were talked about on 92s - +++26 years has gone by and they are. Glass . It was interesting that the message of tweaking the sponsons and gaIning a crack .talk it up

[at100plus]

Mine has it too. I think the vast majority do. I'm not understanding how an unsupported back seat makes it worse...my seat is on two hinges to the floor at the front and just rests on the back deck of the boat. I guess the weight in the seat at that mid point puts stress on that part??? I do everything I can to avoid any choppy water. I hate rough water.

[kellytheaker]

Just exactly where is the cracking on yours sir .on the seat cowl or on the rise of the top deck .thanks

[at100plus]

Just exactly where is the cracking on yours sir .on the seat cowl or on the rise of the top deck .thanks

On the deck right where yours is but port side. Original owner says it was there since shortly after he bought it new.

[at100plus]

Mine. I'm worried the heavier 300 on my boat will make it worse. I'm keeping an eye on it, it's not all the way through can't see anything from inside. I run only calm water tho and baby the boat as much as possible.

[at100plus]

My friend had his fixed. I wonder if it will put stress elsewhere.

[JPEROG]

When the seat bottom doesn't "bottom out" on the floor, it places all of the pressure on the flange of the top deck. That is how the cracks start but like Keith said, it is a flex point in the hull and rough water makes them grow. I added several supports in my River Rocket and glassed the deck joint with 3 staggered layers of 1708 because I knew that it would be subjected to rough water. Here is how it acts- https://www.youtube.com/watch?v=HEnYTXLUABM

Joe

[kellytheaker]

Thanks for the replies, excellent opportunity to see the problem and the fix with reinforcing with the viable cloth .I am a been to this hull but suspect there is some K glass in the lay-up . I don't have a hull sitting in my yard but I believe those knee braces are improved/larger from stock? And it seems you glasses that inner transom wall and floor indetween the kneewall and I see just 2 plywood supports where the cracking on the top deck at the rise . I am sure you have been working with other guys on these fixes. I did see a thread that someone was I swing aluminum off the transom as a knee brace . Is the 300 much heavier th and the 2.5 or similar power plants .Please continue the education if you would .

[JPEROG]

The X is a great motor and I like my current STV as much as any of the others that I have had with motors weighing less. The X is about 150 LBS heavier then a 280 but the torque that it produces and 100 mph cruise speeds are worth any negative aspects that it creates.

I added the front seat mount support, the passenger foot brace, 4 bulkheads, a support from the tunnel top to the outside of each sponson (at a 45 degree angle), bigger knees, a vertical transom support, glassed the entire hull/deck seam with 3 staggered layers of 1708, and multiple layers of glass was added to the transom itself. You can see in the video link that I posted how well mannered the boat is in rough water. The hull weight was 838 before we rigged it.

Joe