Keel-Stepped vs Deck-Stepped . . .

[gettinthere]

Originally Posted by Vasco

Yes, Beneteau for one.

Vasco

Which bene's are keel stepped. I have seen a lot of them and all are deck stepped.
The First performance series?

[Sandero]

All keel stepped hollow masts will leak. If not from the partners which can be well sealed, from all the penetrations for sheaves and wire exits. Not a lots but water can get in.

[Vasco]

Originally Posted by gettinthere

Vasco

Which bene's are keel stepped. I have seen a lot of them and all are deck stepped.
The First performance series?

All the First series.

[Randyonr3]

Originally Posted by defjef

All keel stepped hollow masts will leak. If not from the partners which can be well sealed, from all the penetrations for sheaves and wire exits. Not a lots but water can get in.

Not so....ours has an internal plug at the deck heigth, and any water running down it inside is stopped at the plug and exits the mast at the turning blocks for the internal rigging..
in the area around the outside of the mast to deck, we stuffed the plug in and then poured in a sealer made for such application..
But, what we have found, was that when exploring the colder lattitudes the mast would radiate the cold from outside.. Normally we would wrap a blanket around the internal mast durring the winter..

[Dockhead]

Originally Posted by jdeatsch

Good day folks and be gentle with the new guy...

Old sailor for many years past though mostly in smaller <26' craft. I have been reading my a$$ off on this fine site as you might imagine.

It's time to consider taking the plunge (sorry) and going for the 32-38 foot cruising vessel (sail of course).

I've noticed some are deck stepped masts. This seems absurd to me, is that even a reasonable idea? I've not even considered a NON-keel stepped mast, why would I?

I have noticed in a LOT of photographs that there appear to be a piece of 'pipe' that runs from cabin ceiling to the cabin sole. Is THAT the 'bracing' for the deck stepped mast in an attempt to make it sound?

OR, on the other hand, would I be completely out to lunch here?

As you might imagine, I shall appreciate any and all thoughts, opinions, credentials, and well, you get the idea.

Jim

I think your question has been answered pretty thoroughly by the folks here.

Like others, I don't think there is anything inherently bad about deck-stepped masts. There are plusses and minuses of both types.

One plus of a keel-stepped mast which I think no one mentioned is that if you slack a stay or shroud with no sails up the mast won't fall down.

Another plus not mentioned is that although most of the strength of the rig comes from stays and shrouds, you certainly do get a bit of extra strength out of the mast itself, if it is keel stepped with decent partners.

The big minus of keel-stepped masts is water ingress, but as others have said, that can be controlled and even prevented with good designs.

The "pipe" you talked about is, naturally, to take the compressive loads from a deck-stepped mast. While it might seem that this is a backwards way to do it, actually, it is fairly elegant since this "pipe" will be less intrusive in the cabin space than a whole mast would be, and it does not have to come through a penetration in the deck which creates the potential of water ingress. Nothing wrong at all with that configuration.

[ConradG]

Originally Posted by defjef

All keel stepped hollow masts will leak. If not from the partners which can be well sealed, from all the penetrations for sheaves and wire exits. Not a lots but water can get in.

Not if they don't have any wires or sheaves running inside them...traditionally.

And yes, steel masts are often used on traditional rigs precisely because they don't add significant weight aloft. Smaller scantlings are used because of the greater compression strength of steel to aluminum or wood and the cost is significantly less. Coreten's greater strength would allow even lighter scantling but costs closer to aluminum and with steel, even coreten, there isn't much corossion factor available. (For instance a 1/8 inch steel hull plating can be reduced when coreten is used by strength standards but it is ussually kept the same because a smidgeon of rust-and coreten rusts, decreases it's strength proportionally and the inside of a tube is pretty hard to keep rust out of ). When you start getting into more highly engineered and stayed monstrocities that must reach many more feet abve the water for marconi rigs things get expensive ...and vulnerable.

This compression buissiness is something not quite discussed in relation to deck stepped vs keel stepped here. When a pole is keel stepped and supported at the deck there is a stiffness that is achieved upwards of the deck (one not dependent on the stays) that isn't there with a deck stepped mast. As Brion Toss illustrates in his book "the Complete Rigger's Aprentice", take a piece of uncooked spagetti and put force down on one end, supporting it at the bottom as if deck stepped. Now take one slightly longer but support it a bit above the table by pinching it and put downward force on it and note the stiffness further up. Not rocket science and especially in the taller marconi rig it probably matters very little because the whole thing is relying on the complex system of stays and spreaders. But the keel stepped has the potential to be a little stronger.

Now think of the deck stepped on it's own. Compression to it's base by the stays to the chainplates and via the sides of the hull to the keel where they meet. Run a deck accross and plant that force on it and it is easy to see that iether you need quite a deck, a substantial beam or some sort of lighter and straight pole to take the load. On some metal boats especially where the verticle part of the cabin trunk is such that it is at mast placement, a simple tabernackle welded in can act as a stiffener and create a heck of a load bearing beam and if that tabernacle extends to boom hight for it's top pin then some of the stiffening effect of the deck stepped mast discribed above can be had.

But regardless, propperly designed both will only work well as long as all of their design features are intact-stays, hull, deck, fasteners. I wouldn't let one type discourage me over the other but rather closely assess the way each are implimented on the given boats in question and consider their possibility for failure.

[Bash]

There is no better way to let water into a boat than to cut a big hole in the deck and insert a hollow, slotted tube designed to attract both lightning and rainwater. You can plug it, seal it, boot it, and cast spells upon it, but sooner or latter the wind will jiggle it around and it will leak.

[zeehag]

someone mentioned the deck stepped mast as being because of no t breaking a hole in deck if dismasting.
au contraire, sir, i beg to differ-- the deck stepped masts have been known to rip huge holes in decks they fall from, as the steps to these are glassed into the deck. keel stepped masts tend to break above level of deck leaving a stub to which one is able to rig a jury rig rag set up for propulsion and still maintains intact decking.
annother option is the deck stepped tabernackling mast step which allows the mast to be lowered for canal transits -- eg, europe, erie canal.. some westsails have tabernackled masts, everything hank mccune(yorktown yachts, among others) built was tabernackled from factory.
in my boat, the leaks from rain and downcoming waters is negligible. doesnt come into house--i dont care too much-- i have ways to remove it--is mwrely drops. what i donot want to have to face is total loss of mast and holing deck by a sealed deck stepped mast. lol.. is why i am not planning to cruise my deck stepped ericson 35mII--i PREFER the hollow wooden masts stepped to keel--easily repaired...and the keel stepped feature-- so there is a way to rig a rag should mast rigging fail.

[delmarrey]

Having had both these are my pluses and complaints on a 40' boat, boats of different sizes will have different results.

Keel stepped:
NEG- Water does get into the bilges via the halyards, the base of the mast gets some erosion, the wires run in the bilges, the mast transfer heat/cold into the cabin, the sheave plate requires a tie-rod to keep the deck from arching when heeled over extensively (squeezing the hull), requires a longer extrusion (shipping costs).

POS- It could loose a shroud w/o too much worry of loosing the mast. It could loose either or both the stays w/o loosing the mast, little worry about deck damage around the mast, a lighting strike will most likely go to the keel depending on its base insulation.

Deck Stepped:
Neg- Possibility of rot and/or compression of deck under the mast step, electrical wires need to pass thru deck, mast will most likely come completely down with the loss of a shroud or stay, if I loose a mast little chance of jury rigging something back up like putting my spinnaker pole in the hole depending where the mast breaks.

POS- No arching of the deck, less material/shipping costs all around, easier to step/un-step.


All this said it would not make a difference to me in deciding whether to buy a boat if it were either other then the strength of the rig itself. Personally, for offshore I would prefer the deck stepped providing it were heavily rigged to take a rollover w/bare poles.

[jdeatsch]

Wow ! Just Wow !

Many, many thanks folks for the in-depth discussion and opinions. I had done a search for stepping and step without coming up with much of interest. Show's to go you that it's all in the vocabulary.

I shall go back to my incessant lurking.

Jim

[roverhi]

Unnecessary weight aloft on any boat is not an advantage. If you doubt that, just think of the moment arm differential between the keel and weight well up a long mast.

Corten has been billed as a cure all for steel in corrosive environments. It resists exfoliation better than common steel but still isn't immune from it. Corten has failed miserably in the salt laden environment of Hawaii from metal roof sheathing to the Aloha Stadium. It's better than plain steel but that's not saying an awful lot. In a marine environment, there just is no realistic way to keep Corten steel free from corrosion except with LOTS of maintenance. It can work okay on a hull but not a mast with it's constant abuse from sails, rigging, salt air and spray and the inability to service the interior.

The best that can be said for it, in comparison to aluminum, is it's easier to weld. On really large vessels, we're talking ships, not boats, it may have use as a mast material. Most of the commercial sailing ships of the late 19th/early 20th century did have steel masts. They were built before Aluminum was a readily available material, however.

[daddle]

Keel stepped masts have, when broken above the deck, swung around inside destroying the interior and damaging the hull. Some race rules and prudent owners require a restraining bridle at the keel step to prevent this particular disaster.

[zeehag]

most owners of keel stepped mast carry along on their boats the proper equipment and tools to properly address the problems of the rig potentially destroying the boat--and know how to use them
i have tools for both destruction and re-creation of my rigging.
my two masts are hollow boxes made of spruce wood. they neither conduct heat nor cold inside a boat nor do they have as much tendency to destroy house and home as do aluminum ones--they DO create quite a mess, yes. i hope i manage to avoid that small chance disaster. friends of mine in mid pacific this past summer had all his chain plates snap. keel stepped mast. did not lose mast. cannot say that if you have a deck stepped one.

rollovers dont usually happen under bare pole situations-- usually you are under sail and having a good/bad time in/not in weather....i would prefer to reef well and early to rolling over/knocking down.

[stillbuilding]

My father owned a 65'+ steel masted schooner which had been build in NZ and is still based on Gold Coast, Australia I think. Heavy motor sailor design with the limitations of that type. Did not really sail well but no doubt served its design function OK. No details of mast thickness sorry. Don't think it would make any difference if masts were Corten or Mild steel. Only corrosion resistance is different. Steel masts have been used in much bigger commercial cargo sailing ships a very long time ago, have been occasional steel-masted yachts around all my life. Surely been well tried and tested and put back in the box for all the above stated reasons.

[jjones1349]

On my Nonsuch...keel stepped with no shrouds at all. Stepping is very fast while others have to connect all their shrouds. The again, Nonsuches are an entirely different breed that requires its own manual for sailing. It's been a fun learning curve so far.