bulkhead

[ntica]

Hi. Want to ask you about a "new bulhead" in my boat. I found this pic' here on Sailfar. do I have to put some material between the Mahogny and the hull before I fit it with the polyester plastic???
On the pic', there's something "white'ish"? silicon only?

[skylark]

It is a good idea to avoid hard spots, for example where the wood bulkhead touches the hull and then creates a stress point.  You can separate the hull and bulkhead by a small amount using foam or other spacer material, and then tab it in with glass cloth and epoxy. 

[Leroy - Gulf 29]

Can you use some of that foam that goes down between a floor and laminate flooring?  IIRC,  I read somewhere that it would work.  Of course, I'm old and blonde so could be mistaken  :D

[ntica]

thanks!

[ntica]

thanks!

Why I ask this is becuse, there aren't any bulkheads at all in my boat. And I thought it would be "smart" to stiffener her up. Is it nessecery you think?
see pic'

[skylark]

It is somewhat dangerous to play amateur nautical architect from afar, but...

I would want adequate support under the mast, if deck stepped.

[Captain Smollett]

Why I ask this is becuse, there aren't any bulkheads at all in my boat. And I thought it would be "smart" to stiffener her up. Is it nessecery you think?
see pic'

I'm sorry, I cannot tell from that picture...

Were there once bulkhead in the boat, but they've been removed for some reason?

If they are drawn in the plans by the designer(s), probably best to go back with that.  (Showing my ignorance of IF's, but I'd find myself quite surprised to learn they have no bulkheads).  If they are on the plans, I'd put them back, and in the same place. That's just me putting all my bets on the designers expertise, though.

The bulkheads may well be different from the mast support.  Supporting deck stepped masts is a 'science' (or art?) all unto itself.  It's one of the known 'weak areas' of the pre-liner Alberg 30s, for example (and other 60's era Alberg boats, for that matter).

The original A-30 had a laminated wooded support beam that is notorious for becoming delaminated and even separating from the overhead.  In 71-ish, as they phased in the hull liners, Whitby went to an aluminum support beam encapsulated in fiberglass and THROUGH BOLTED to the one-inch-thick bulkhead.  This is MUCH stronger.

Incidentally, Yves on his circumnavigation (his boat is a pre-liner A-30) had mast support issues, and went to an aluminum sister 'improvement,' which is what a lot of the contemporary owners of pre-liner boats have done as well.

This is just one approach, of course, but it outlines that the mast support MUST be well engineered if it has any hope of lasting and, well, supporting the mast.

So, perhaps the bulkhead need not be right under the mast, but I'd think the mast support beam should be tied into the bulkhead (which ties it to the hull, etc, etc).

[ntica]

Skylark. There is a mast support, a huge "balk" across the roof and a support "balk" down to the keel! And the "roof balk" crosses the roof and attached to the hull also.

[ntica]

"Were there once bulkhead in the boat, but they've been removed for some reason?"
cpt. No there hasn't been any bulkheads on these early models. And there is a huge beam across the roof to support the mast, also a "beam" from the roof to the keel. it seems strong and realiable.
Why I merntioned the "bulkheads" was becuse the "pressure" against the hull... but I don't know... ?just a thought. what do you think?

[SeaHusky]

If I am correct, the earliest production years didn't have any bulkheads.
In my opinion the bulkheads are the biggest drawback of the IF:s interior making the main cabin tiny only to create a V-birth for the kids or more often bags of sail. If the mast support beam is original I would keep it and use the whole cabin space as a living area with perhaps a bulkhead fore of the fore hatch to make a sail locker and maybe a curtain aft of the head.
Pics of your boat would be helpful.

[ntica]

oki... will get some pic's tommorow! And yes it would be rommier without the bulkheads. I'am thinking strenght only. but I'm not a boat designer...

[Captain Smollett]

cpt. No there hasn't been any bulkheads on these early models.

and

If I am correct, the earliest production years didn't have any bulkheads

Well, I am both surprised and enlightened.

Thanks, guys, grog to you both.

Now, if they did NOT have bulkheads and they have a record at-sea of holding up, my opinion (worth slightly LESS than you are paying for it) is that the boat 'should be' fine without adding them.

That's a big "if," though...I'd be really, really sure that the non-bulkhead version has been adequately tested in the 'big tank' ...  YMMV, as always.

Could you perhaps split the difference and add knees?  Gain a little strength without breaking up the interior space too much, and of course, one could add structural diagonals if you felt you really needed to, and they likewise would not compromise the interior to any appreciable degree.

Just some thoughts, as I am likewise not a boat designer...

[ntica]

cpt. Yes thats a great ide', ad some "Knees". The IF community recomend this on the chainplates to ad strenght in that area.
thanks!

[ntica]

here...

[ntica]

 "perhaps a bulkhead fore of the fore hatch to make a sail locker and maybe a curtain aft of the head."
Sea Husky... there aint no "fore hatch" ??? ( If you mean what I think)
My English is not that good.

[SeaHusky]

Sea Husky... there ain't no "fore hatch" ?

Doh! ::)
I forgot that the early models also didn't have a fore hatch.
Well I mean to use the front end of the V-berth as a storage locker for light and/or wet stuff such as sails.
Maybe you would want to add a seaworthy hatch so you don't have to drag the wet genoa all the way through the boat...

[marujo_sortudo]

A fore hatch is a very good safety feature too if the other hatch becomes blocked while your inside.  E.g., by fire, or something preventing it from opening.  I was very glad to have mine this year when a misplaced folding solar panel fell in the way of the hatch and kept it from sliding open.

[ntica]

Marujo... good thinking. will look into this. thanx

[Captain Smollett]

A fore hatch is a very good safety feature too if the other hatch becomes blocked while your inside.  E.g., by fire, or something preventing it from opening.  I was very glad to have mine this year when a misplaced folding solar panel fell in the way of the hatch and kept it from sliding open.

I wonder if this is an advantage of having a sea hood over the sliding hatch.  There's no way anything could trap my hatch (short of hitting so hard it busted the sea hood, of course, or wedged IT into the path of the sliding hatch) and keep it from opening.

Scary stuff.  Getting locked out of the cabin is one of the things that shortened Heather "Flight of Years" Neal's journey.

My little boat lacks a fore hatch, and another disadvantage (perhaps less so in Sweden) is the reduced 'through the whole boat' ventilation one provides on extremely hot days.

[CharlieJ]

I can quite easily see a blocked companionway.

A fire in the galley which formost boats is right AT the companionway would do it bigtime!!

Graham Byrnes of B and B ( and a small boat circumnavigator)  won't design a cruisiing type boat WITHOUT a fore hatch simply as an escape route.