Strange Cracks in Chines

[CamB25]

https://www.amazon.com/photos/share/XFe ... y0uz9w2ePI

These photos are of cracks I found in a few starboard chine locations. I had pulled the hull outside to spray primer on the cap. Warm, sunny day. The bottom of this boat was completely repaired many years ago and now I have cracks appearing (and dripping water). The boat hasn't seen the water since 1990 and hasn't been washed for a couple of years. Stored in a relatively warm shed (no lower than 40 F). The cracks are not near any trailer support rollers.

Any idea how these cracks could form? Bizarre!

Here's a couple of shots of Bahama Blue Baby! I hot-coated a light spray of paint over my final primer layers. Hopefully some color will remain after I complete the final sand.

https://www.amazon.com/photos/share/ULe ... GeoZOdrM34

The weather is finally breakiing here...went nuts with the spray gun this weekend!

[buzzk]

Have you cut the deck out and checked the stingers? Sometimes the stringers would break loose from the hull on the 25's. I've seen it happen on other 25's and read about it on line. The cracks looked similar to yours from what I remember. If the stringers have broken free from the bottom I would also check the crime while making the repairs. The boats I looked at also had some chime damage from the bottom working. Once the stringers were reattached with the proper cloth and epoxy they never had any more trouble.

[CamB25]

Deck has been replaced. We reinforced the stringers with 1808/epoxy all the way/both sides. 100% re-done from the keel up.

I think you might be on to something.... long term shrinkage from all the reinforcements?

[Tommy]

I'm wondering if it's just water that wicked up through the gel coat over time and created a huge linear blister. I also wonder if it's from a bad repair of a previous grounding or trailer-loading mishap. I hope some of the experts here will chime in, but I gotta think you will need to grind all that bad gel coat away to see what you are dealing with underneath. I experienced a blistered hull on a Boston Whaler and ended up grinding out a few hundred blisters sized mostly like nickels, dimes and quarters, but a few 2-3 inches in diameter. I've never seen your scenario before, so I hope it is just contained to one area. By the way, your paint job looks GREAT!

[CamB25]

Thanks, Tommy. She will be Blue!

The bottom was stripped, ground, repaired, and prep up through a first coat of paint (just to hold the work). This is new damage since 2010. I'll need to grind out those areas to attempt to find a root cause. Might be remnants of an old, old repair that has let go.

[Rawleigh]

Are the chines molded into the hull on the 25's or are they hollow cavities like some of the lifting strakes are? If hollow I would drill a couple of holes and see what comes out. Then thicken epoxy and inject it with the caulking gun tubes starting at a point above the damage and just pump it full to make it a solid chine. just a thought that might save a lot of grinding.

[Yannis]

Cam,

To me it looks as if the whole area has been repaired in some way or another in the past.
It looks to me as if there was some damage that was patched so as to cover a repetitive pattern of marks that were caused by a mechanical impact. I’m thinking of this by looking at the symmetrical and aligned marks in the first picture, if you magnify it.
Also, I’m almost compelled to say that it may not just be a gellcoat crack; it looks like it is a cracked grp.
Over this crack, it seems that there may be some sort of wooden/ply structure that is wet, and the water has seeped through bringing along this brownish color.
I would definitely grind away all adjacent gell and look under it to see what’s going on.
Good luck.

[SteveM]

Nice job on the paint. Nice color too. Keep us posted on the progress, looking forward to seeing it done.

[CamB25]

The chines are hollow cavities, but I don't believe they are open to the interior of the boat. In cross section they look like a triangle of fiberglass - not open to the interior of the boat. At least this is what I see from my old pictures of the boat with deck removed, and from working on the bow thruster tube which bisects one chine.

The cracks remind me of freeze damage...water in a closed cavity freezes and splits the weakest surface. It is possible that the damage I am just now noticing is many years old, from when the boat was stored outside. I haven't spent any time under the boat in years. Also, The water droplets felt and smelled "old", if that makes any sense.

I'm guessing that it is an old repair that let go at some point. The water has been in those chines for XX years. I sloshed it around when I moved the boat outside.

Thanks for the feedback!

[Yannis]

Cam, read this old thread:

(I don’t know how to properly copy the link)


Strake crack advice pls.

[Lars]

Strakes are fun...

You may remember my previous post about finding old poorly repaired damage in the hull of my 25. Well, more coming up..
It appears that the boat had a number of quite bad rock encounters, penetrating the laminate. So also on the strakes at a couple of places.

Patchup removed, revealing a proper crack


Grinding shows damaged laminate all the way through


Repair needed from both sides


Nothing on the inside here...


Fortunately I have found a highly skilled glass company that I am very happy with. The boat has been drying out in the baking oven for two months now, and is getting to the point where repairs can be completed. Moisture was off the scale on the meter. Not cheap, but the previous owner who didn't know about the botch job is pitching in.

I have learned a few things about the Bertie-strakes:
1. They are always integral to the hull. Never added post-molding
2. Sometimes they are left without adding anything on the inside (like mine). Vulnerable to damage, but easier to access and repair from inside. Thankfully nothing else that is hampering access at the damaged locations
3. Sometimes they are completely filled in. Solid but costly approach.
4. Sometimes they are covered over after molding, leaving a hollow triangular shape inside. May get waterlogged and if so prone to cause hull moisture ingress, as insides are poorly waterproofed. Those of you who have had water-filled strakes: I would do a moisture test of surrounding hull areas

Can't wait to have a solid hull. Taking the opportunity to do some drive train upgrades as well, now that everything is out. Updates to follow in due course.

The fun we're having!..

[Lars]

A picture of the repaired area from the inside. Access hole cut through the bottom of the galley module.
As you see, nothing much on the inside of the strakes on mine. Then you can visualise the inside of the ones that have a glass covering "lid".

[CamB25]

Very interesting. Thanks for posting, Lars. If I remember correctly, you have a RIVA 25? What year? Where were these produced?

Thanks
Cam

[Lars]

That’s right, Cam. It’s a 1972 Riva Bertram 25 Sportfisherman. They were built in Sarnico Italy, in Bertram hull molds and to Bertram specs. I wouldn’t be surprised though, if the Riva build is more Howdy, and less Sportfish.

But she is about to get solid again, and fresh engines are on their way. Fingers crossed she will eventually be niiice!!..

[Waytooslow]

The cracks remind me of freeze damage...water in a closed cavity freezes and splits the weakest surface. It is possible that the damage I am just now noticing is many years old, from when the boat was stored outside. I haven't spent any time under the boat in years. Also, The water droplets felt and smelled "old", if that makes any sense.

!

This is what I am thinking I just don't know if you could have missed it for several years. I would drill a small hole and see if more water comes out. You got to repair anyway. Sorry

[scot]

I believe you are right Cam, I think that is an old repair that was poorly executed and finally let go. Dig it out and fix it right, as I know you will.
Mine was cracked down both sides of the chines, on the hull sides. Multiple small fractures extending 4-7 ft in the cabin area. The cracks did not go all the way through the layup. This appears to be common, from pounding the hull I assume. Also, I think Bertram expected too much from those chines, as the weight of the cabin transfers into the hull sides, which compresses the protruding design on wave impacts, causing them to be over stressed.. IMHO. But the chine design is one of the coolest aspects of these hulls. I ended up grinding off the gel-coat the entire length of the boat and adding 4 layers of 1708 to the outside. Wiped out several weekends last summer., very tedious trying not to screw up the hull sides

It's the unpleasant discovery work that eats all the time on these projects!! I hope I am done finding surprises, but the bottom is yet to come.

The blue is fresh, I like it.

[CamB25]

Thanks, Scot. I have screwed up the terminology...these cracks are in the lifting strakes, not the chines. I read your write-up on the chine issue many years ago, and mine are good. They are now somewhat reinforced with the new deck.

When I get back the boat shed I will drill holes in the aft-most section of the strakes and drain the water. The water that dripped out the other day was "old", if you know what I mean.

[CamB25]

Spent some time on my back with a small grinding wheel. These pictures are taken from the ground looking up at the strakes. The dark spots are water droplets. You can make out a crack running through the repair area. Looks like an old repair that has let go. The pink stuff seems to be bondo. It's packed into the triangular cavity formed by the strake. All of this will need to be ground out and repaired - FUN!

https://www.amazon.com/photos/share/Nns ... sxkRFSWx9T

I drilled a hole at the aft end of this strake, no water. I also drilled a hole at the aft end of the 1st strake (closest to chine) and very stinky water started to drip out. I put a paint bucket under the drip to collect the water. I'll be back there Friday to check the level.

[Lars]

Ouch!

That’s a proper all-the-way-through damage. It should ideally be repaired from both sides, but I guess it’s impossible for you to access the inside. I am a bit concerned that much of the hull integrity will be carried by the inside strake cover patches rather than the continuously molded hull/strakes.

Trust me though, I know exactly how much fun it is to discover old bodge-jobs.

Good luck with the repair.

[Yannis]

Cam,

Anything that you might have to cut/rip open to gain access from the inside, is less structural than the integrity lost from not mending this from the inside. (old chinese proverb!)

Good luck.

[Lars]

Old Chinese proverbs are Greek to me...

[Tony Meola]

Cam

Back in the day, a lot of guys used Bondo. For some reason those that are not in the know, think it is water proof. Worst thing you could use but they used it. Dig it out and let it dry real good. I would get some denatured alcohol, put it in a sprayer and soak the area real good to get it clean and help it dry. Then take a hose and flush it real good with fresh water and let it dry again.

[Waytooslow]

Bright side--at least you found it before you launched the boat. Would be a pain to think you are done and then have to repair again. todd

[CamB25]

Lars - the hull closes off all of these strakes. No need to breach the hull to repair this. I have a magic potion of 2 part foam, epoxy, and fiberglass planned for these areas!

Yes, I am glad I found them now rather than later!

Tony - good advice. I have the sections open now. It will be months before I get around to this fix.

[Yannis]

Cam,

If this is anything like the 28, the hull closes all strakes’ inner surfaces alright, albeit with a thinner layer than the hull itself, like an inner membrane so to speak.
The structural rigidity is most probably assured by the outer part of the strakes’ surfaces.
Given the total breach of the outer hull in the area, I would add 3-4 glass strips on the inside, as per normal practice, of narrower to wider layers of glass.

Lars,

Chinese serves better as an unknown, greek shouldnt sound as strange...one in three or four english words are of this origin.
I, who speak both these languages, I am sometimes puzzled by the pronunciation of a word, not by its meaning.
What do you not understand by the word aeroplano? Perhaps airplane? Airplane in chinese should be considerably different...

[CamB25]

16 oz of dirty, smelly old water after one week of drip, drip, drip from a small hole drilled in the aft end of the 1st strake (closest to shine). This is not the strake with the long crack.

https://www.amazon.com/photos/share/2xy ... xpXwabgd50

I proceeded to kick it over when starting to spray. Last primer coats and a quick hot coat of Oyster white on the inside. One last sand to 320/400 and we'll be painting for real!

https://www.amazon.com/photos/share/v4w ... HQDoGdmB74

[Lars]

Interior looks great.
Must be a pretty good feeling to see it coming together now!..