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Olson 34 Mast Step Construction

brianb00

O - 34
Hello All,

I have an Olson 34 and am wondering about the mast step construction technique. I spoke with Ballenger (spars) about this and they indicated this was a very thick fiberglass hat tied into the bulk head. What he wasn't quite sure of was if the structure was foam filled or wood. It was his belief that Ericson continued with Pacific's approach, which was a glass (mat/roving) over foam approach but couldn't rule out the use of wood. Does anyone know for certain ?

I will be pulling the rig soon, adding an adjustable mast step for rake tweaking, and while I am in there might as well inspect the entire area for any sign of damage. IF it is foam I likely won't do any core sampling, if it is wood I likely will.

Any help would be appreciated.

Brian
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Hat thoughts

All the hat stringers in our boat are indeed foam filled, AFAIK. I can detect foam when probing inside the limber holes to clean out the gunk (!) anyhow. :rolleyes:

When we had the keel rebedded, the yard manager looked it over and he estimated that the keel bolts go down thru the overlaps in the "hat stringers" to provide strength -- he thought it looked well-engineered. The main stringers go back under the settee fronts on each side, BTW.

The bulkhead is glassed to the hull all the way around, but is not, AFAIK, directly part of the mast step "hat".

Having said all that, a surveyor I know told me that it is normal to see a little bit of down-flex in the big "hat" that the spar rests on -- evidenced by some small cracks in the oozed resin along the bottom of the wood risers glassed to the tops of all the hats for the sole pieces to screw into. The wood risers on that one hat do show a tiny bit of cracking along their resin interface with the hat stringer. Those thin risers have no structural function, and exist only to give the sole screws something flat and uniform to bite into.

http://www.ericsonyachts.org/infoexchange/showthread.php?t=6303&referrerid=28
There are a few photos of the port side settee in this prior thread. Fuel tank was out. I will try to put in an annotated photo here also.

Best,
Loren
 

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brianb00

O - 34
O 34 mast step

Thanks Loren for the photo montage. My boat as well feels like foam beneath the luber (sp) holes, but I thought maybe there is a plywood box involved as well, just guessing. I was considering glassing in a drain tube in hopes of eliminating the exposure of the mast step to bilge moisture, but maybe more work than I imagine.

My boat has seen a lot of hard sea miles with many ocean races and two races and returns to Hawaii. I am going through it looking for any signs of stringer cracking or bulk head seperation.

There are a pair of small wood tabs at the base of the forward bulkhead, as you enter the forward cabin. CLoset on left, cabinet on right, the small tabs tie the end of the bulkhead to the cabin sole. Mine appear to be working loose as they vibrate a bit when the engine is running. I don't believe this is structural in nature. I was considering removing the tabs and glassing the bulkhead to the sole, then putting back the wood tabs and associated screws, just to prevent them from working loose in the future. A friends Express 37 has a similar treatment. Any thoughts ?

Your fuel tank project looks similar to one I completed last summer. I did a nearly exact replacement and had to make nearly identical cuts in the seetee to get it in after the tank manuf. added a bit more length to the return fitting. I also had to do trimming on the seetee cover to accomodate thicker material I had the manuf. use for both the tank and hold down tabs. I also added an inspection take out beneath the tank in the seete wall, facing the mast. This allows me to get in there to clean out that space.

Thanks for the input and photo's.

BRian
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
There are a pair of small wood tabs at the base of the forward bulkhead, as you enter the forward cabin. CLoset on left, cabinet on right, the small tabs tie the end of the bulkhead to the cabin sole. Mine appear to be working loose as they vibrate a bit when the engine is running. I don't believe this is structural in nature. I was considering removing the tabs and glassing the bulkhead to the sole, then putting back the wood tabs and associated screws, just to prevent them from working loose in the future. A friends Express 37 has a similar treatment. Any thoughts ?
BRian

Yeah, those little teak trim pieces on each side at the bottom are both a bit loose on ours - been the same since we bought the boat in '94.
I was thinking of making an L-shape piece of lay-up for each side, both sides. Maybe about 1" on the flange and then screwing it to the sole molding with short ss screws and covering both sides with new teak moldings just for looks. No boat structure is involved, but it would look better IMHO.

That's way down my project list at this point.

This winter I want to get our new furnace in. At present I have that overweight piece of 3/4" plywood out that is the laz. shelf. Next comes out the tabbed-in heavy pieces of plywood around the aft water tank. All that wood (15# in the shelf alone!) will be replaced with honeycomb panels... and the new Webasto will have to fit in under that shelf somehow some way...
:rolleyes:
Routing the duct under the head counter and behind the nav. seat should try my patience to the very max.

Oops, sorry to start hijacking your thread.

Best,
Loren
 

brianb00

O - 34
Water heater

That is a great thought, replacing the plywood with honeycomb. I was about to replace my water heater as the original is getting rusty. Lets see, should we make a production run of small bits of plywood replacement ?

I keep looking at the engine cover/stairs wondering how that could be fat reduced.
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
That is a great thought, replacing the plywood with honeycomb. I was about to replace my water heater as the original is getting rusty. Lets see, should we make a production run of small bits of plywood replacement ?

I keep looking at the engine cover/stairs wondering how that could be fat reduced.

That one-piece engine cover is probably better left alone for now, at least on our boat... It is quite a fancy and well-done molding.
I did replace our water heater many years ago. I epoxied in a plywood panel under the nav seat and put a square Atlantic brand SS tank in, ss inner tank too. Our factory tank had a corroded out shell and the inner tank was aluminum and was corroding alum. oxide into the water system.

My only regret was not finding/creating enough room under that nav seat for a six gallon tank. I went with a 4 gallon to make the install go easier. Ever since then we run a little short of hot water the morning after we anchor out...
The problem is that incoming cold water cools the tank contents as you withdraw the hot and it just does not stay really hot very long. Not a big complaint, but a detail I did not think through completely. With 20-20 hindsight I might be able to shoehorn the slightly-long 6 gallon tank into that space. If you are interested I could try to post some photos of it some time -- new thread of course. :nerd:

Cheers,
Loren
:egrin:
 
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CTOlsen

Member III
I too am an O-34 owner, and former O-30 owner. On the O-30, George Olson used wood, vice foam, on the load bearing stringers. There were 2 of them, one of which supported the mast. I replaced it with a Ron Moore fab'd OEM GRP replacement (which fit like a glove, btw).

I've been an O-34 owner for a whopping 7 months, and did some reconnescence on my mast step upon delivery of my boat to the Chesapeake (via truck). I bought it from the original owner who sailed it casually on Lake Ontario all of 6 months a year. Otherwise it was layed up in a yard shed. He had the yard attend to his boating needs, but, it appeared nobody ever worked on the step.

The mast step firing strips were toast. The original oak firing strips had rotted away, and the mast sat 1/2" lower than original. upon disassembly, I found the butt to be anchored via 4 SST lag screws. The screws led me to believe that this boat also had a mast step constructed of wood;Spruce. the lag bolts are about 3" long, so they should protrude into the wood (or possibly foam). My reecommendations are to pull one boat once the rig is pulled and sample via the bolt hole.

I've attached a few pix. Hope they're helpful.
CTO
 

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brianb00

O - 34
Olson 34 mast step

CTO,


Thanks for the note and photos. Looks like a similar set up to mine, except the step on mine is encased in glass mat. From your pics it looks removed ?

I don't believe mine has sagged, but that is why I am checking it all out wih the mast pulled.

Did the Ron Moore replacement have foam inside ? Or was it solid GRP or Hat section ?

Thanks
for the note,

Regards,

BRian

On the O-30, George Olson used wood, vice foam, on the load bearing stringers. There were 2 of them, one of which supported the mast. I replaced it with a Ron Moore fab'd OEM GRP replacement (which fit like a glove, btw).

I've been an O-34 owner for a whopping 7 months, and did some reconnescence on my mast step upon delivery of my boat to the Chesapeake (via truck). I bought it from the original owner who sailed it casually on Lake Ontario all of 6 months a year. Otherwise it was layed up in a yard shed. He had the yard attend to his boating needs, but, it appeared nobody ever worked on the step.

The mast step firing strips were toast. The original oak firing strips had rotted away, and the mast sat 1/2" lower than original. upon disassembly, I found the butt to be anchored via 4 SST lag screws. The screws led me to believe that this boat also had a mast step constructed of wood;Spruce. the lag bolts are about 3" long, so they should protrude into the wood (or possibly foam). My reecommendations are to pull one boat once the rig is pulled and sample via the bolt hole.

I've attached a few pix. Hope they're helpful.
CTO[/quote]
 

CTOlsen

Member III
Brian
THe stringers are all glass, wrapped in wood (or possibly foam). There are 1/2" oak firing strips on top which suport the cabin sole. I'd be interested to know if yours, and Loren's, have the oak strips. Since the boat was nearly stock when i cought it, I believed this to be original construction.

Oh, and the Ron Moore step was all glass, with gelcoat. inverted "C" section (channel). Fit perfectly. Sold the boat in July after buying the 34. See: http://olsonuldb.com/olson30/MemberPages/111Namesake/index.htm

CTO
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
http://www.ericsonyachts.org/infoexchange/showthread.php?t=1526&referrerid=28

There are some photos of our sole pieces back in place in reply #72. I never took any when we were doing the sole work -- that was before I bought a digi camera. :rolleyes:

And yes, our boat also has the wood firing strips on top of all the hat sections.

We do need to remove the sole sections for revarnishing sometime, but that might be next winter. Whenever that happens I can take some photos of the bilge areas.

Best,
Loren
 

brianb00

O - 34
mast step strips

Thanks Guys,

I miss read CTO's thread a bit. My boats fir strips, while still in reasonable shape are being replaced. CTO's pictures show the base of the step where the luber hole is. This is the area I was a bit worried about but CTO's and mine look very much alike. It all looks like it is holding up well inspite of the annual ocean pounding.

On to completion of sole replacement.
 

brianb00

O - 34
Olson 34 Stringers

I confirmed the stringers are foam filled this weekend. I have some small cracks near the luber hole in the mast step stringer. I was planning to glass in a set of tabs and drill a small hole at the end of each crack to stop any potential migration. Any reason to be concerned ?

Brian
 

CTOlsen

Member III
I wouldn't worry about small cracks on a boat that is 20 years old, rode hard on the Pacific. I'd do exactly what you are doing- drill them and make doubler tabs. I'll look for the same on my boat this weekend.
Thanks for the feedback on the foam core!.
CTO
 

brianb00

O - 34
Olson 34 mast step construction revisit.

Hello All,

After spending a few more years bobbing around the Pac Ocean off San Francisco I have gotten back to working on my mast step. I am busy glassing in the mast hat, the large ring frame that the mast rests on. There are small cracks where it contacts the hull under the mast and along the hat to port and starboard, both on the bow and stern side of the hat. I have drilled a couple of sample holes in the top of the hat. The top layer of the hat is 1" thick roving and resin. Beneath it I believe is balsa wood. As I said in my 2009 post Buz Ballinger told me he thought it was foam, but could be wood. The early Olson 34 (known for years here as Ozone) has an all balsa cored hull. In the past I thought this was foam as it felt that way from the lubber holes.

So, here is what seems odd, but interesting in the construction: It appears that this hat was only bonded to the hull with filler/bondo/resin+cabosil and no roving was applied at the hull/hat joint forward and astern of the hat. Of course there is considerable roving under the seats to port and star. where the hat extends and terminates athwartship (as shown in photos shown in previous entries to this thread). I have sanded off the bilge paint and exposed the area around the hat and there is no evidence of roving. However, all the other ring frame elements Are throughly framed with roving, as one would expect. It seems the hat was pre fabed, and then layed in with roving at the ends and bondo at all other points along the hull, with lubber holes being the exception.

I am guessing that the mast step hat depends on the end connections (roving) and balsa to be the primary support as the real load is compression, not tension. I have taken the boat out in a heavy sea way and placed my fingers under that hat where I have some cracking, thinking I might feel movement as the boat pounds into the chop. Nothing seemed to move at all.

Anyone have any opinion on this construction ? I am assuming that glassing the hat into the hull firmly, with 3 layers of heavy roving could not hurt anything ?

Regards,

Brian
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
About the only thing I would add is that instead of roving, these days I use biax for any strength-needed stuff like you are doing. You get twice the fabric over a joint with the biax.

Loren
 

brianb00

O - 34
Finished tabing in the mast step.

After a lot of grinding, sanding, and permanent lung damage, I got the mast step base retabbed to the hull with 3 layers of bi axial glass, the result is approx 3/4 thickness and extending 2" onto the hull and the same onto the step (vertical surface). After a 48 hour cure cycle at about 100 deg F. I took here out for a 44 mile sail in ocean and bay. The mast still stands, the hull is not cracked, and no apparent wear on the tabbing. The boat goes much faster :), as shown in this attached photo.
 

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