Strake crack advice pls.

[Yannis]

Well, not everything should go right, right?

In the first pic you may see that on the LOWERMOST strake (not the middle one) there are some white marks. This is salt, in FINE powder form, that came out of a minute crack as I finger tapped the area. The crack runs the upper corner of the strake (where the strake meets the hull), for about 60 cm / 2 feet.



The same area after some chisel work. You can see that the rain water created some vertical salt marks.


After some more chiseling, there seems to be an interrupted fine mat layer (over the strake, hull side) and some brown (wood?) on strake surface, under all gel and anti foul.

What does this all mean?
1. Is the strake shape part of the hull shape and therefore the boat is cracked?
2. Is the strake an addition to the hull and, as such, glassing it or epoxying it would suffice?

I don't remember having witnessed water in the bilge last summer, BUT, some little water in the bilge under the cabin sole I explained to be rubber water tank leakage which was put under there. Had there been a crack to the boat the water should have been considerably more, no?

Can somebody please gimme some advice as to where to start from? Thanx.

[Kevin]

I believe the strakes go on after the boat is out of mold.....not positive though. What I do know is they are hollow. Water will not get into bilge...just fill the void between strake and hull. I have a crack on mine right where bulkhead is from engines to cabin. Drill whole in strake at lowest point and let it drain. I have repaired mine twice if not three times over 10 years. I put blocks under keel on lift last year to help distribute weight better. I may fix cracks again this year and see if the hold up with the new supports in place. Hope this helps.

[Tony Meola]

Yannis

Check the inside of the hull in that area to make sure there are no cracks or what look like bad repairs from a prior owner. I am not sure if they are hollow or solid. I am sure Capt. Pat can tell us.

I would strip the paint from that area and open the crack. Flush with denatured alcohol and fresh water. Let it dry out real good. Warm dry weather and if you need to a small fan will help speed up the process. To really dry out real well, it may need a week or two on its own. Depends on how much water is in there.

The best way of repairing, would be with epoxy not sure if you need any cloth if it is only superficial. but if you need to build the strake back up you will need cloth.

I am sure those who are better at glass than me will help out.

[Yannis]

I believe the strakes go on after the boat is out of mold

Kevin thank you. To be honest, this is the answer I was praying to get. It's so much simpler to deal with a strake that has somehow got unstuck, than with a cracked hull.
What surprises me though is that the strakes are hollow ! If that is confirmed, I will drill a hole at lowest point and let drain; then seal drill hole and crack.

Check the inside of the hull in that area to make sure there are no cracks or what look like bad repairs from a prior owner.

Tony, I did just that. I looked inside the forward cabin sole hatch and it looks like the layers of roving are "uninterrupted" since ...the beginning of time, albeit, the area is painted white by previous owners and I can always spend time wondering if this was done to mask fiberglass mending - it doesn't look like it though. Also, I believe that the hull skin in that area is so thick, that it would have required a major repair had something occurred in the past.
I will have to look around and check for any other cracks, on this or the other strakes too.

Somebody told me that this incident happened because of a big wave shock, how probable is that?

PS: During the first year, I played James Bond for a while and flew over a few waves, but it didn't bang so hard...or so I thought !

[Kevin]

Yannis,
I suspect that you would easily be able to identify an interior crack, or a crack that made it all the way through the hull. That glass is very distinct looking on the inside. I do not think bilge kote paint would mask it. It would crack along with the glass, no hiding it with paint.
I believe mine were do to improper storage at the yard, forklift usage and my original cradle set up on my lift. I doubt wave impacts would do that to these boats, especially at the speeds we go.
K

[Yannis]

Kevin,

The area in question is inside the forward sole compartment, that is, I removed the fwd hatch and it's all the way aft, near the other compartment but you can't have access the other side. Anyway, I looked with a torch and nothing seems to be cracked or anything, just the flimsy laying of the last roving, you know, with the sharp edges not carefully stuck.

I believe you're right, it should be due to uneven forklifting, or, in my case, trailering from the sea to the yard (some 500 m.).
Oh, and also the 43 or so years of hardship.

I need to know, though, if the strakes are layed-up after de-molding. Can somebody confirm this?
Thank you.

[CaptPatrick]

Yannis,

No, the lifting strakes are integral to the mold... Once the layup crew had gotten enough glass worked into the voids if the strakes, they then bridged over them with roving, leaving the strake hollow.

Trying to attach and glass in the stringers after the hull is laid up & pulled would be very labor intensive and impossible to duplicate on every hull. No manufacturer would do that except on a plug hull to make the final mold...

[Yannis]

Captain, thank you.

In other words, the outer skin of the strake must be much thinner than he rest of the hull, no?

And how "structural" is this damage, according to the pics? How can it be fixed ?

[Navatech]

In other words, the outer skin of the strake must be much thinner than he rest of the hull, no?

Not necessarily... But then again, if the strake is hollow and the top side of the strake is done like the rest of the hull it really doesn't matter...

And how "structural" is this damage, according to the pics? How can it be fixed ?

The strake itself, based on my understanding of the previous information provided, isn't really structural... It's an addition to the hull to facilitate better handling... I would do a little exploratory drilling... Say a 10 or 12 mm drill bit and aim for the other side of the strake... I.e. not into the bottom... Just to see what's there... As for fixing, I would try sanding out a V shaped grove (wide "mouth") and then filling it with epoxy mixed a filler material (cabosil or even saw dust)... About the consistency of between mayonnaise and peanut butter... Probably more toward the latter as otherwise it might drip or sag too easily... It's basically a cosmetic rather then a structural repair...

[Yannis]

Say a 10 or 12 mm drill bit and aim for the other side of the strake... I.e. not into the bottom...

So, a somehow angled (upwards) drill hole, starting at the outer vertical side of the strake going in, and penetrating the "upper" strake side which is the hull. This should come inside the boat and I should then check the thickness of the hull at the "bridge" roving, as Captain explains it.

My "plastician", the guy who made my refrigerator etc, usually works with a mix of polyester with glass dust. One can fix the consistency as needed. This is how he fixed the hundreds of small and bigger holes all around the boat so far. Would this material be OK for filling the grove and drill hole ?
Thanx.

[Navatech]

My "plastician", the guy who made my refrigerator etc, usually works with a mix of polyester with glass dust. One can fix the consistency as needed. This is how he fixed the hundreds of small and bigger holes all around the boat so far. Would this material be OK for filling the grove and drill hole ?

Yes, that's general idea... One thing though, resin ("polyester") doesn't have very good bonding (glueing) properties... That's one of the reasons why boats are built "wet on wet"... I.e. each layer in the laminate layers is laid down on top of the previous one before it has completely dried up... Otherwise there's no good chemical bond between the layers and the resulting laminate won't be as strong as it can be... Epoxy is a glue so it's bonding properties are significantly better...

The one issue with epoxy is that once you have used (most types of) epoxy you can't use resin (or related products like gelcoat) on top of the epoxy... Your "plastician" should do the work the same way but use marine epoxy... It will be a better repair!...

[Yannis]

I've also read what you wrote to Vince about epoxy. Thanx.

[Yannis]

On second thought, could someone confirm that the thickness of the "bridge" layer is the same, as in the rest of the hull?
This could make me avoid to drill all the way through, just to check this parameter.

In case I use epoxy for the repair, as opposed to polyester resin, could I in the future apply an anti-osmotic treatment or nothing can bond with epoxy anymore?

Thank you.

[CaptPatrick]

Yannis and Matt,

The lifting strake is approximately 1/3 or less than the overall thickness of the hull between strakes. Do not drill all the way through the hull, rather just the strake.

Using a 1/4" drill bit, (6 mm), drill up into the horizontal plane of the lifting strake, just penetrating the strake void. Make this hole at the aft end of the strake.

Drill another hole into the vertical plane of the strake at the forward end of the strake. Be sure that the boat is blocked bow proud so that trapped water will drain. The use of a Shop Vac may help you out. Suck from the aft end, blow from the forward end. You may need to drill more holes, but not through to the inside of the boat...

Once you have the water drained, flush the strake with denatured alcohol to further dry the inside of the strake. Plug the hole(s) on the horizontal plane and fill the strake through the hole on the vertical plane at the forward end of the strake. Alcohol will combine with water and once drained will further remove moisture from the strake.

Repairing the strake is another process and I'll cover that at a later time...

[CaptPatrick]

Now for your repair...

Sand down the strake(s) to bare fiberglass, including a 3" lap onto the hull both above and be low the strake(s). Fill in any deep areas where cracked.

Starting with the vertical planes, epoxy glass 1708 biaxle 45º weave, lapping onto the hull by 2" - 3" and letting the fabric extend below the bottom plane of the strake. Allow this course to harden to point that the epoxy is leather hard. Trim of the excess glass flush with the horizontal plane of the strake. Allow this course to cure for 24 hours.

Do any necessary clean up of excess epoxy before it hardens.

Epoxy glass the horizontal plane and allow it to harden for 24 hours. Make sure that this course caps the first course extending over the edge of the first course.

Once fully hard, sand away any lip and taper the tab into the hull.

Using 6 oz 0º-90º weave fabric, epoxy glass over both previous courses. Keep the epoxy on all of your glass work to a minimum, applying only enough to wet out the fabric and use a resin roller to eliminate all bubbles.

After 24 - 48 hours lightly sand all and fair. You can make up your own epoxy fairing compound or use Awlfair or 3M Vinylester Premium Filler.

Do not use polyester over epoxy. Select an epoxy barrier coat over the repair.

[Yannis]

Captain Patrick, I appreciate your time and assistance.

Could you perhaps clarify for me the following:

Fill in any deep areas where cracked.

I understand to fill in with epoxy, correct?

Trim of the excess glass flush with the horizontal plane of the strake. Allow this course to cure for 24 hours.

You suggest this first application to extend up to the lowest extremity (edge) of the vertical plane, without going underneath; then you suggest the same be done below, on the horizontal plane, AFTER the previous work has cured for 24h; that is, do the job, so far, in two distinct steps. Right?

Select an epoxy barrier coat over the repair.

Does a barrier coat need to be done now, or can I wait till after the season considering the boat will remain wet for 5 months max? Can I just get away with it, at this stage, with the antifowling that I will anyway apply for the season?
The rest of the hull, that which is not epoxy treated, will it require another type of barrier? If yes, how do the two barrier products meet?

The crack, in my case, should be no more than 2 feet long. Do I need to do the job for this length (plus a few inches on either side) or do I have to do the whole strake length?

Thank you. I'll keep you posted as the work evolves.

[CamB25]

Good reading for my strake crack issues! Don't know why I referred to the strakes as chines...maybe my respirator has a whole in it!

thanks Yannis!

[Marlin]

The lifting strikes on my 31 are / were hollow filled with foam. I ground thru the arf end of one and watched the water drip out for days. I think they were added to help lift and stabilize the boat in beam seas. They are very thin and long and I would not think they can ever be dried out entirely and see no value in attempting to do so. I have never read a thread on this site where someone had had seas rip them off. Remember, the enemy of good is better!