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15-02-2016, 18:07
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#1
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Registered User
Join Date: Feb 2016
Posts: 13
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Change to Deck Stepped Mast
Hello, new to the site but have bee a lurker for a while....
I have an old Tayana 37 in need of some serious work, the boat is out of the water and I'm going to start work on the deck in a few weeks. One of the projects I want to undertake is changing from a keel stepped mast to deck stepped. I have some corrosion at the base of the mast and don't want to go to the expense of a new mast...
Has anyone undertaken this project and what are the pro's and cons.
Thanks
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15-02-2016, 19:43
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#2
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Registered User
Join Date: Oct 2012
Location: rhode island
Boat: irwin 37 center cockpit
Posts: 68
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Re: Change to Deck Stepped Mast
i would stay away from changing that, the keel step is very good. how bad is the corrosion? if you cut it and have a new piece put on it won't cost much, and as long as its done right it won't be a week spot. or just cut it and raise the step a bit, both are lots easier than making it a deck step. (you would need to reinforce the cabin top alot, both inside and out, build a compression post thats strong enough to suport your rig, re-wire your mast lights, build a mast step, then you get to deal with the interior work, new headliner, cabin sole, table top, ect.) and thats just a start.
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15-02-2016, 20:59
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#3
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Registered User
Join Date: Apr 2007
Location: Marina del Rey, California
Boat: President 43 Sportfish
Posts: 4,105
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Re: Change to Deck Stepped Mast
Quote:
Originally Posted by Adamaris
...One of the projects I want to undertake is changing from a keel stepped mast to deck stepped. I have some corrosion at the base of the mast...
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That is a terrible idea. Simply effect a repair to the base of the mast.
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15-02-2016, 21:16
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#4
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Registered User
Join Date: Nov 2015
Location: Netherlands
Boat: Ohlson 29
Posts: 1,519
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Re: Change to Deck Stepped Mast
Welcom to CF!
Doesn't sound like you need a new mast - maybe post some pics?
But whatever you do, do not go from keel to deck stepped
(Which I doubt would be cheaper than repairing whatever you need for your keel stepped mast.
It's not like you can just shorten the mast and stick it on the deck )
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"Il faut ętre toujours ivre." - Charles Baudelaire
Dutch ♀ Liveaboard, sharing an Ohlson 29 with a feline.
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15-02-2016, 22:16
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#5
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Moderator
Join Date: Nov 2011
Location: aboard, cruising in Australia
Boat: Sayer 46' Solent rig sloop
Posts: 28,400
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Re: Change to Deck Stepped Mast
It will benefit you to talk to someone to engineers masts, but I'll give it a little go. The deal is that the mast sections (its thickness) are predicated on having both the support of the mast step and from the deck penetration. You would be better off to cut off the corroded part , and shorten the rig, keeping it essentially the same. the cheapest alternative.
In essence, you risk dismasting.
Ann
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Who scorns the calm has forgotten the storm.
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15-02-2016, 22:31
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#6
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Registered User
Join Date: Oct 2010
Location: Wandering the US Gulf Coast
Boat: 78 Pearson323 Four Winds
Posts: 2,212
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Re: Change to Deck Stepped Mast
Adamaris, that's a known issue with my model of boat. The aluminum mast sits on a steel step in a wet bilge. A common solution is to have a new step made from aluminum. Or maybe some dense phenolic plastic type.
Cutting off the corrosion and building the step taller to compensate allows everything else to remain the same. Usually maybe 2-3 inches needs removed. There was a gent who specialized in building the new steps for mine at around $400 if I recall correctly.
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Life begins at the waters edge.
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15-02-2016, 22:41
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#7
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Registered User
Join Date: Oct 2010
Location: Wandering the US Gulf Coast
Boat: 78 Pearson323 Four Winds
Posts: 2,212
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Re: Change to Deck Stepped Mast
Some pics for reference. Hopefully yours doesn't look like that last pic.
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Life begins at the waters edge.
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15-02-2016, 22:50
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#8
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Registered User
Join Date: Jun 2014
Location: Up the mast, looking for clean wind.
Boat: Currently Shopping, & Heavily in LUST!
Posts: 5,629
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Re: Change to Deck Stepped Mast
Quote:
Originally Posted by four winds
The aluminum mast sits on a steel step in a wet bilge. A common solution is to have a new step made from aluminum. Or maybe some dense phenolic plastic type.
Cutting off the corrosion and building the step taller to compensate allows everything else to remain the same. Usually maybe 2-3 inches needs removed. There was a gent who specialized in building the new steps for mine at around $400 if I recall correctly.
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G10 is the name of the "plastic" you're looking for here. The better grades of it are as strong as, or stronger than aluminum. Albeit it's not cheap, or as easy to machine. But for the most part you can still use wood working tools.
It's a high pressure, epoxy, fiberglass laminate. Google it, or look on www.Matweb.com
Ann's correct, in that you can't just take a keel stepped mast & use if for a deck stepped mast on the same boat. Or at best, you might sneak by, if someone does all of the math on mast design for you, & gives it the nod.
IE; If for some odd reason you're serious about such, talk to a rigger first.
Though even then, you're looking at $5-figures to do such a conversion, or close to it, easily. So you're better off to fix what's there.
The reason why you can't do such a direct swap, is that you can use a much less stiff, & lighter weight tube, if a mast is keel stepped, than if it's deck stepped. And in general, keel stepped masts are more robust.
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15-02-2016, 23:07
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#9
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Registered User
Join Date: Oct 2010
Location: Wandering the US Gulf Coast
Boat: 78 Pearson323 Four Winds
Posts: 2,212
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Re: Change to Deck Stepped Mast
Thanks UNCIVILIZED, frankly I didn't realize G10 was in the "plastics" family. Instead thinking it was more kin to fibreglass, which I guess is sorta plasticy, too. Sorry, not big on the details until I tackle a specific task, then I focus. Still need to tackle this repair on my boat.
ETA, just looked at the link. G10 it will be. Something I can work with myself as I can't afford to let someone else work on my boat. My preference anyway.
I think this is a Tayana step. At least there is no deck tie rod like mine to deal with.
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Life begins at the waters edge.
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16-02-2016, 00:09
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#10
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Moderator
Join Date: Nov 2011
Location: aboard, cruising in Australia
Boat: Sayer 46' Solent rig sloop
Posts: 28,400
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Re: Change to Deck Stepped Mast
Four Winds,
Your deck tie-down is a good deal. Keep it. The simplistic explanation is that it keeps everything together that you want to stay that way. Uncivilized will be back soon to explain why.
Ann
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Who scorns the calm has forgotten the storm.
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16-02-2016, 00:35
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#11
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Registered User
Join Date: Oct 2010
Location: Wandering the US Gulf Coast
Boat: 78 Pearson323 Four Winds
Posts: 2,212
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Re: Change to Deck Stepped Mast
Copy, Ann. Intend to keep it, just need to work out the attachment method in the new keel step. Also, might need to run a die on it to make more threaded area since it may need to be cut to match the new dimensions. Bit of a puzzle. BTW, I understand why it's there though wondered about that for some time until reading about it on the forum. (several hours a day since about '08)
Apologies to the OP for bringing attention to my issues. But hopefully it is pointing out the better course of action on the Tayana step is a repair/mod and not a total redesign of the mast configuration.
I believe the idea was to cut the mast significantly to a deck stepped length. And as UNCIVILIZED pointed out the wall thickness and flexibility are unsuited for that. Not to mention the cost to rerig, compression post fab, deck mods, etc.
__________________
Life begins at the waters edge.
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16-02-2016, 01:26
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#12
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Registered User
Join Date: Mar 2010
Location: UK, Australia, Europe
Boat: Custom Catamaran
Posts: 879
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Re: Change to Deck Stepped Mast
Quote:
Originally Posted by Ann T. Cate
The deal is that the mast sections (its thickness) are predicated on having both the support of the mast step and from the deck penetration.
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I'd hate for someone to take away from this thread that a keel stepped mast can't be cut down and used as deck stepped. As Uncivilized said, best to talk to a rigger.
n
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16-02-2016, 01:41
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#13
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Registered User
Join Date: Jan 2016
Posts: 429
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Re: Change to Deck Stepped Mast
Adamaris,
a quick Google shows your boat to be popular enough that it has a number of different owners' groups.
If the mast section used was always the same maybe another owner will have kept the drawings of the new step he had made.
You won't be the first to need to fix this I imagine.
Raising a mast in a controlled manner without a crane can and has been done.
Support with halyards while adding a shackle below each stay, jack up an inch, repeat. Obviously jacking points & load spreading are crucial.
Corroded section of a mast can be removed with hand tools.
Use penetrating oil and loosen the step's fixings days or more before you even start lifting - don't want to mess with stuck bolts after you start.
Plan carefully, discuss with others, arrange for assistance if you need it.
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16-02-2016, 02:33
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#14
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Registered User
Join Date: Jan 2016
Posts: 429
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Re: Change to Deck Stepped Mast
I'm in the UK but if I were in the US I might try Rig-Rite.
They seem to have a wide range of parts for spars & other stuff - maybe they've been asked before.
If not they have a custom build option but I've obviously no idea whether they're good value or not.
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16-02-2016, 02:37
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#15
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Registered User
Join Date: Feb 2016
Posts: 13
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Re: Change to Deck Stepped Mast
Hello and thanks for the replies...
One of the reasons I was considering changing to deck stepped is that it is highly likely that the mast has been shortened before. The mast step is almost up to the cabin floor level, the inside of the mast has quite severe pitting over the first foot and although I havent removed the external paint I suspect filler has been used to hide he effects of corrosion. There is some minor bubbling of the coating which I dont really want to scrape until the mast is off the boat.
The boat is from the mid 70's and I even wonder if the mast is original to the boat, many boats of this era had wooden masts. Ive also seen several models of this boat with deck stepped masts, which made me consider this as an alternative...
If I cant resolve this issue I may have to consider a used mast as a replacement.
Thanks again
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