SailNet Community banner
  • SailNet is a forum community dedicated to Sailing enthusiasts. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more!

Rotten core around Mast Step-repair

25K views 52 replies 11 participants last post by  superiorvoyager 
#1 ·
When I bought my 32'Voyager 4 years ago it had a slight leak at the Mast step. I caulked the Bolts and it seemed to fix the problem but it turns out all it did was keep the water from coming through the bolt holes in the inner skin and the water just pooled inside and rotted out all around the Mast step causing the step to start depressing the deck. I took the mast down this fall with the intention of doing repair in the spring but discovered that the core had totally rotted out for a good foot around the step (maybe more as I haven't opened it up yet but the Fiberglass skin at the front of the step had cracked and you can see in and there is no wood left there. I've read lots of posts here about replacing the core but have had a number of people including one boatyard suggest instead of replacing the Balsa Core with the same to remove the old core and make that area solid fiberglass/West System. My father had a boat repair place repair the deck on his old boat a number of years ago and this is how they did it and it did seem to hold up well. Obviously the weight would be greater but what other disadvantages would there be? Has anyone done this?
 
#32 · (Edited)
FWIW...Here is an example of where plywood or any compressabal core material should have never been used..It dosent have any anymore...Problum fixed forever.

To clarify the pictures..The first is Irwins origional lay up of their mast steps on their 41' ketches..you can see they layed op a solid 1" layer under the plywood and then a soild 1/2" over it but inbetween was 2" of plywood core just plain saturatrated and copressed almost 3/8 of an inch. What did thay save maybe 50 bucks back in 1983..woopee.
 

Attachments

#33 ·
Well The Weather warmed up (+10C) and all the snow melted so I decided to open up the deck and see what I have. Turns out the wood core was only 1/4" thick (the fiberglass skin on the out side is quite thick and is mat between cloth) so I will probably just go with fiberglass. The problem I found is that the rot is worse than I thought. I cut out a 12" X12" square where the mast step and found it was a soaking wet mush. Used a Coat hanger to poak in and see how far back the rot went and discovered that the area that is rotten is about 3'X5'. The only part that is structural is right under the Mast so my thought is to just replace a 1'-2' section under the mast (make it solig glass), clean out about 6"-8" rot around the edge and put glass and epoxy in that and then inject epoxy into the rest. the rest of the roof feels prety solid despite the rot, probably because the glass is already so thick. How does this sound for a solution. Obviously I won't do the fiberglassing part untill the spring as it is dropping well below frezzing at nights now. With it open and tented now it should allow the area to dry out over the winter.
 
#34 ·
There is not much strength to epoxy resin without cloth reinforcement. As well, if you have to clean out rotten core 6-8" past the cut out you cannot reliably remove it without cutting the top layer off. 6-8" is too far without better access. I'd cut the top skin until I found dry core and replace the rotten core with ply or balsa and solid glass under the step as you plan. Then reglass the top, fair and paint. Make sure you grind a good bevel at the edges, they say 12-1 ratio but 8 or 10 to 1 should be ok. This means if the top layer is 1/4" thick the bevel should be 2"+ to get a good overlap, each side.
Brian
 
#35 ·
The problem with that is that from what I found by probing with a coat hanger the rot goes right to the edge of the cabin so I would have to remove the entire cabin deck. That would be a major job (5'X4' minnimum) and probably more than I am prepared to do. Hopefully there is a way to repair this with out having to replace the entire cabin.
 
#37 ·
I agree with mitiempo

It will always be a compromised repair but it could be "Good enough" compared to the value of the boat and all that jazz..Resin will not adhere to wet material though and they make a product that will penetrate and reinforce rotten wood better then epoxy..I would use that instead if you decide to go that route. The rest sounds like a great plan.
 
#38 ·
I don't know what product Stillraining is referring to but I'm not aware of one that will "reinforce rotten wood better than epoxy". It will still be rotton wood with not much more strength than rotten wood - albeit "petrified". If you have to cut open the deck to repair the mast step all it means is a bigger area. Same process expanded by a few square feet. If the area is 3 times the size it won't mean 3 times the work. More materials, a bit more labour and a much better result.
Brian
 
#39 ·
Although it is a great boat and serves us well it is a 1979 that I picked up for $2700 so I suppose that I am looking for a "good enough" fix. I want to make sure that it is structurally sound (ie. around the mast) but when you walk on the deck despite the fact that it would appear the core is rotten the deck itself is pretty solid probably because the fiberglass is so thick. I should mention that my plan also includes washing the entire area with acetone and than flooding the rotten areas with acetone and letting it then evaporate out untill spring. Experience from the past has taught me that rotten and or wet wood can be dried out fairly well in this way. The issue will likely be the joint where the repair is made and potential of cracking there.
 
#40 ·
I will bow out mitiempo...I have never used the stuff just read about it and heard others praise of it...Just wanted to get across that epoxy will not adhere to or penetrate wet wood where the other stuff is supposed to seek out moisture.

Carry on
 
#41 ·
I understand your reluctance to do the whole cut open and repair job. But remember that with freeze/thaw cycles if it remains moist the deck won't be solid forever. I'd like to hear more about this magic fluid that seeks out moisture though.
Brian
 
#42 ·
If you are referring to my comment about acetone it is an old practice that is commonly used in antique restoration ect. The acetone doesn't "seek out moisture" but rather if it comes in contact with wet wood will combine with the water and simply speed up the evaporation of the water (many people say it wicks the water away) that is already in the wood. Try it sometime. Take two pieces of equally wet and rotten wood and soak one in acetone and leave the other as is. Put them both in a warm dry environment and the one with the acetone will dry twice as fast. If you take a moisture meter and measure the moisture content in a piece of wood and then soak it in acetone. Let the acetone dry out and measure it again and you will find the moisture level has dropped. The problem I see with doing this on a a core is that first you have to get the acetone into that area and then it has to be able to evaporate out, therefor I am not sure how well it will work in this situation. I guess my reluctance with doing the whole thing is the difficulty I see in trying to do a nice job of joining a new roof to the sides of the cabin. Pluss the cost and time of the full Job.
 
#43 ·
No, i was referring to Stillraining's mention of a product better than epoxy for reinforcing rotten wood. You shouldn't have to go right to the edge with the cut, just closer than 8". I'd leave a lip of about 2" to taper the new glass to. It should be fairly easy to gouge the wet core out if 2" is as far as you have to reach. The cabin sides are probably not cored as thay usually aren't. I agree that the acetone helps but it still requires good evaporation to take place.
Brian
 
#44 ·
Yes I would love to know what that material is as well. I do remember reading about a company that claimed their epoxy could be used to reconstitute rotten wood but when it came down to it the rotten wood had to be totally dry and the epoxy ended up just holding the fibers together. With the wet core I am dealing with where I cut the outer skin away I didn't have to scape or gouge the rot out. It is so rotten I just used a shop vac and vacumed it up.
 
#45 ·
Based on my experience and reading it doesn't exist - or exists but doesn't really live up to the claims made for it. According to West Epoxy you can thin epoxy with acetone, lacquer thinner or denatured alcohol upto 5% but the loss in strength is 35%. This will hold true for any brand as really they are formulators, working with the same basic items in different proportions.
Here's a link to West's Fibreglass boat repair manual. http://www.westsystem.com/ss/assets/HowTo-Publications/Fiberglass-Boat-Repair-and-Maintenance.pdf
The information that concerns your repair is in section 5, pages 28 to 33. But it wouldn't hurt to download the whole pdf as it's full of good info that would apply to any brand of epoxy. I prefer West and have been using it for almost 20 years. (I paid for my manual as the internet didn't exist then) I hope this helps. I've also included below a section from their Wooden boat repair manual concerning thinning epoxy.
Brian
 

Attachments

#46 ·
While there are some epoxy manufacturers/sellers that claim their epoxy products will restore wood's strength... I'd have to point out that very few of them will work well if the wood isn't BONE DRY. Cutting out the wet, rotting material and then laying the area up with a new core and leaving a ring of solid glass around the opening itself is really the best way to repair something like this.
 
#47 ·
This has been very helpful in putting together a plan of Action. weathers getting cold again and looks like snow so I will now put this project to rest till the spring and do lots of research. The other big project for the spring will be dealing with the blistering gelcoat but that is for another post. The West system manual looks like it will have lots of great ideas.
 
#48 ·
Well I ended up just cutting out the area around the Mast step (not the whole cabin deck) and laying it up with solid epoxy and glass. Made a rock solid repair there but with the rest of the deck rotten and spongy I decided to try some other options. Taking the advise here, but not wanting to replace the whole cabin deck (4x6 feet) I tried something different. I drilled a series of 1" holes in the deck, used a coat hanger to dig out rotten material and then pored epoxy resin into the hole followed by strips of resin soaked fiberglass cloth then patched over the holes and painted with a non slip paint. You couldn't tell there was a repair and the deck ended up totally ridged. I know this isn't the proper way to repair it but it seems to have worked and I now have a totally solid deck. After a season of sailing it is holding up great. Here are a couple of pictures. Unfortunately I didn't take any pictures of the finished product.

FIrst I drilled the holes
 

Attachments

#50 ·
If you removed all the moist core it should work. But if not the moisture left will cause rot and with freezing cause delamination as well. By using epoxy in the holes you drilled any future repair becomes much tougher to accomplish.
 
#52 ·
There really isn't anything left to rot in there as the entire core was totally rotted. After sitting with a 2 foot section cut out at the mast step for the winter it was fairly dry (after the -50 weather we had this winter it was freeze dried). My hope is that there is enough fiberglass in there that is bridging the inner and outer skin that it will keep for years to come. If it does fail it will mean removing the whole deck but repairing it properly would have meant that anyway. Here's hoping.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top