Mast Step Repairs

[Greenman]

So my mast step was compressed with mush balsa, can you see why?

here's a closer look

closer.........


opened up

cleaned and wiped down with acetone

odd double cored mast step

my first ever attempt at doing a repair

I hope the closed cell foam lasts better then the balsa

I know it looks like a hack job now. I had to cut deeper than I had hoped.

The surgical instrument


I am almost done and will post pictures of the complete repair as well as the aluminum plate I am putting under the step to attach blocks to when I lead the lines aft next winter.

[s/v Faith]

Does not look like a hack job to me.  Should be a good solid step when you are done.... thanks for taking and posting the pictures.

  You are probably planning to do this already, but just in case make sure to bevel (taper) the edges of the fiberglass around the repair so that you have a good surface for the new fiberglass to bond to.

  If you are using the old fiberglass panels that you cut off of the surface (I do not favor this, others do).. make sure you bevel their edges also.  You do not want to create a stress point along the margin of the repair.

  Good luck. 

[Greenman]

I actually made the cuts at a 45 degree angle, for extra bonding, and will feather out the edges more on the finish round.

[SV Wind Dancer]

Thanx for posting...it's on my 'to do' list and it will be a first time thing for me.

[wallo9]

ya thanks for the pictures.

[sailorbum]

Very nice.  I'm about to do the same with my cockpit floor; just waiting for the weather to warm up some more.   

TrT

[maxiSwede]

Nice work Greenman!

I would bevel (?) overlap with at least 2 inches to make a good bonding. Guess that's what Faith tryed to say too.

I think I would go for epoxi rather than polyester/vinylestet because it makes a stronger bondng... sort of glue effect.

just my two cents... or more like euros, due to inflation  ... 

[AdriftAtSea]

I hope you're using epoxy for this repair. Epoxy resins have much better secondary bonding (adhesive) characteristics than do polyester or vinylester resins. They're also stronger.  However, they are more subject to heat-induced deformation, so painting them a light color is important. Just curious, why did you go for foam at the center of the mast step area rather than going with solid glass there?  Solid fiberglass would certainly resist the compressive forces better and has fewer issues with water penetration than even a foam core material would.

[newt]

This is an interesting topic. My decks (35 years old) were recently redone by the same person that did the original layup in 1975! He was an artist- but he did use foam (for stiffness) and he used fiberglass instead of epoxy resins! I protested, but you know I cannot tell where he did all the work. The boat looks new without one line to show where he worked...
The repair in this photo is forward by the second stanchion. On the deck. The doghouse is original. Sorry it is so dirty, It is a boatyard after all...

[Jim_ME]

Hi Greenman, and welcome. Admire your taking on the boat repair project, but I do share Dan's concern about whether the foam core strength will be adequate for the concentrated load of the mast.

Did a quick search online and found this page comparing the strength properties of foam vs balsa core...
http://www.balsacore.com/balsa_core_specifications.html
The charts show that the foam strength is only a fraction of the original balsa.

I saw on one page that general closed cell marine foam has a compressive strength of about 40 psi (pounds per square inch).

If you read this West Epoxy website, the strength is many thousands of psi
http://westsystem.com/ss/west-system-epoxy-for-fiberglass-repair/

so there is a huge difference.

If I had the deck opened up as you do, I would not only reinforce the area directly beneath the mast as Dan suggests, but consider laminating a solid fiberglass beam to spread the mast load out over any bulkhead/beam and door opening below (unless there is a compression post beneath the mast--I'm not familiar with your particular boat). If your deck is that deteriorated, then what is below it may also have degraded over time, and spreading out that load will increase the strength of the whole system.

The lateral loads on the sails/mast become high downward loads on the mast in reaction to the tension on the stays, so I would advise erring on the conservative side in this mast step area.

Good luck with it.

Jim
 
 

[Jim_ME]

Greenman, Here's another website with more information on the strength of foam, a comparison of various foam materials and densities with end-grain balsa and other materials...
http://boatdesign.net/articles/foam-core-properties/index.htm

It appears that the foam cores start at about that 40 psi compressive strength and go up depending on the foam density that you use.

It looks to me that the thickened pad in the step area was designed to stiffen the deck in this area and is perhaps wide enough to spread the mast load over a larger area especially transversely (athwartship) and may have spanned an opening in the bulkhead like a doorway opening? I would be concerned about how much stiffness that pad would have with the foam that you have used to replace the balsa core.

Laminating a new solid pad with cloth/resin would take quite a few layers to match the core thickness, may be more than really necessary. Perhaps using thicker layers of roving/mat would build the thickness quicker and strong enough?     

It seems like you want whatever you do to be at least as strong as the original balsa deck and pad/beam, and if you are planning to use the boat in "Sailfar" conditions, it may be a good idea to go beyond that and upgrade the area (again, especially since you currently have the deck core exposed) You will have access to the bulkhead and any beam, etc from below and could beef that up after the deck repair, if needed. The mast step/support is an area that many of the  boats (especially smaller ones) were under designed and developed problems with, and is a good place to put some extra work into. 

Best wishes for this project and the others you have underway. -Jim

[Leroy - Gulf 29]

McMaster - Carr sells fiberglass in various thicknesses and widths.  I purchased a piece about 5/8" thick by 3' long by IIRC around 8-10" wide  Am going to use it for backing plates on the thru - hulls instead of sealed wood.  Just letting you know that there are commercially available chunks of fiberglass out there.  Am aiming to install the thru hulls per Maine Sail's suggestions.

[AdriftAtSea]

Maine Sail's photo tutorials rock.  He's a pretty nice guy too.  If you haven't had a chance to read his photo tutorials, I'd highly recommend you take a look. They're located at http://www.pbase.com/mainecruising/boat_projects

[Greenman]

I went with the foam because thats what the fiberglass repair shop recommended. Also to address some of the items above,

There is a compression post below the mast;
Also a structural bulkhead;
I put 3 layers of glass/mat above the foam to build it up to original height; and
thats it.

Maybe not the best job in the world but it won't leak, which was my main issue, and won't compress for at least another 35 years.

Once the weather clears I will do the finishing touches and post more pics.

Thanks for all the advice.

Oh BTW I spend a lot of time on Maine Sails website, you're right.........it's awesome!

[sailorbum]

I'm chiming in to defend polyester as a resin.  I don't know anything about core strength re:the mast step. 

There is a local fiberglass guy here in Grand Rapids that has been doing f/g since the 1950's when he was in the Coast Guard.  He only uses epoxy if someone has already used epoxy on a boat.  He has done lots of wild and fancy carbon fiber and other exotic things with epoxies and polyesters.  He convinced me that for most of my small hull repairs polyester would work fine.  It was like changing religions after all I've read [supplied by the epoxy industry] but has saved me a couple hundred dollars already.

Check photos out at http://fiberglassproductsinc.com.  Some amazing repairs all with polyester.

Now,what anchor do you reccomend?   )

[CharlieJ]

Check photos out at http://fiberglassproductsinc.com.  Some amazing repairs all with polyester.

Now,what anchor do you reccomend?   )

 ROFL- five pounds lighter than you can haul off the bottom!!!

Seriously- do a search- you'll find many many lines posted on  the subject here on this site.

On the polyester resin- as a pro boatbuilder and restorer, I use either polyester or epoxy as the job calls for. I agree that polyester is perfectly suitable for most repairs on polyester/glass boats.

[AdriftAtSea]

One major reason I recommend epoxy is it is a lot more forgiving for the novice boat builder than is polyester resin in many ways.  Properly using polyester resin to make a structural repair take a bit more knowledge and experience to get the same strength of repair as you would with epoxy resin. 

As for anchors... I like the next gen ones, and carry a Rocna...but this is not an area where we want this discussion to go....   The blood gets awfully deep?kind of like when hackers discuss linux distros...

[sailorbum]

LOL!   
1) I'm using both resins as I see fit. 

2) I haven't bought an anchor yet.

3) I've got Ubuntu loaded on an old Compaq laptop, though my daily tool is an iBook.  I've played with Red Hat, SuSe, Slackware, and Turbolinux back in the day.  I gave it all up for the boat and my geek powers are fading fast.   

As an honorary member of the Spoon Society, I just like stirring up trouble.  )

[newt]

Charlie, looks like you use fiberglass polyester resins just like the guy up here. Do you prep the area in any special way to make it stick? Sailorbum- Linux is the true religion