SailNet Community banner
1 - 20 of 27 Posts

·
Registered
Joined
·
144 Posts
Discussion Starter · #1 · (Edited)
New Bulkheads & Interior Framing

The interior is gutted, bulkheads are out, and on the home stretch with the grinder.

I'm getting ready to install new bulkheads, and fit the interior with ribs and stringers, keeping it all very basic.

A few questions:

1) There are 2 existing stringers (stiffeners?) on each side attached to the hull that span the length of the boat. Large sections of these are missing/cut-out from a refit with a PO. The stringers are basically a closed cell foam with a 2/3 layer continuous tab. Can I lose these, and expect the newly installed ribs & stringers to provide the support for necessary stiffness?

2) What is the recommended spacing on the ribs?

3) I can't be sure if the old bulkheads were original, but they appear to be. They are 1/2" ply. Should I upsize to 5/8"? Would 3 layers on the continuous tabbing be sufficient?

4) The boat is not in a climate controlled facility. My average daytime temps are in the high 50s low 60s. My average nighttime temps are high 40s to low 50s. Will a low viscosity resin with fast hardener work?
____________________________

Update (Boat Specs):

Boat Make: Laurin Koster
LOA/LOD: 28' / 26'
Displacement: 6600 lbs
Mast: 33' / 160 lbs
Link: LAURIN 26 sailboat specifications and details on sailboatdata.com

The attached line drawing gives the basics, but my my boat was retrofitted with a 2' bowsprit.
 

Attachments

·
Over Hill Sailing Club
Joined
·
3,688 Posts
Some pix would help. There's no way to venture any advice on structural elements without some kind of picture or specs. Those temps are great for epoxy work. I wouldn't use fast or slow hardener unless I wanted to speed up the process but that sometimes results in a smoldering can of gelled resin before you can use it all. Working inside, I hope you have a good organic vapor mask. Most bulkheads I've ever seen in 30-40' boats are 3/4" ply.
 

·
Registered
Joined
·
4,304 Posts
Got to know the boat as there are generally more of them to compare notes on

The fast hardener along with some heat lamps should kick it well enough during daylight hours BUT the FULL cure will still be extended

I preferred the MAS high viscosity resin as I found working with 2:1 was more simple as I had to mix many small batches as I worked
 

·
Registered
Corsair 24
Joined
·
4,594 Posts
Re: New Bulkheads & Interior Framing

The interior is gutted, bulkheads are out, and on the home stretch with the grinder.

I'm getting ready to install new bulkheads, and fit the interior with ribs and stringers, keeping it all very basic.

A few questions:

1) There are 2 existing stringers (stiffeners?) on each side attached to the hull that span the length of the boat. Large sections of these are missing/cut-out from a refit with a PO. The stringers are basically a closed cell foam with a 2/3 layer continuous tab. Can I lose these, and expect the newly installed ribs & stringers to provide the support for necessary stiffness?

2) What is the recommended spacing on the ribs?

3) I can't be sure if the old bulkheads were original, but they appear to be. They are 1/2" ply. Should I upsize to 5/8"? Would 3 layers on the continuous tabbing be sufficient?

4) The boat is not in a climate controlled facility. My average daytime temps are in the high 50s low 60s. My average nighttime temps are high 40s to low 50s. Will a low viscosity resin with fast hardener work?
what size boat?

we did 3/4 inch bulkheads full tab like you want to do...on my islander 36

much better tabbed to the hull than original plus we used foam to gap the bulkheads from the hull

time will tell if its a decent job I guess:)
 
  • Like
Reactions: Kielanders

·
Registered
Joined
·
144 Posts
Discussion Starter · #5 · (Edited)
Forgot the specs guys, apologies:

Boat Make: Laurin Koster
LOA/LOD: 28' / 26'
Displacement: 6600 lbs
Mast: 33' / 160 lbs
Link: LAURIN 26 sailboat specifications and details on sailboatdata.com

Yes, I have a $50 3m paint/organic respirator (with many replacement cartridges & prefilters), goggles, and tyvek suit.

I used MAS Epoxy on a kayak kit years ago and liked it, but we can't get it easily up here, so I was going to go with West System since it's available.

I'll get some recent interior photos posted later today.

The attached line drawing gives the basics, but my my boat was retrofitted with a 2' bowsprit.

Thanks.
 

Attachments

·
Over Hill Sailing Club
Joined
·
3,688 Posts
Forgot the specs guys, apologies:

Boat Make: Laurin Koster
LOA/LOD: 28' / 26'
Displacement: 6600 lbs
Mast: 33' / 160 lbs
Link: LAURIN 26 sailboat specifications and details on sailboatdata.com

Yes, I have a $50 3m paint/organic respirator (with many replacement cartridges & prefilters), goggles, and tyvek suit.

I used MAS Epoxy on a kayak kit years ago and liked it, but we can't get it easily up here, so I was going to go with West System since it's available.

I'll get some recent interior photos posted later today.

The attached line drawing gives the basics, but my my boat was retrofitted with a 2' bowsprit.

Thanks.
That's the respirator I use and have not had any problem. Have never used epoxy other than West System because it has always worked so well. Epoxy, as you probably know, can be nasty. When I forget or am too lazy to dig for the respirator, even for a small job, it can give me a wicked headache. Same with 2 part paints.

I'd probably redo the stringers where they've cut away. They were put there for a reason and it's no big deal to do it now. I'd also use 3/4" ply for bulkheads. It gives you some meat to work with as far as framing openings. Certainly use it if you're going to put in any watertight bulkheads, which might be something to consider. It's not as if a few pounds is going to make much difference.
Nice looking boat. Good luck with the refit.
 

·
Registered
Corsair 24
Joined
·
4,594 Posts
now that I remember I think I went 7/8ths or an inch on the main bulkheads and 3/4 on the forwards for the lowers...

there are some pics on my islander 36 refit thread
http://www.sailnet.com/forums/gear-maintenance/115890-islander-36-projects-paradise.html

if it helps any...its not a pro job but its perfect for what they are designed to do...I also made new plates at the time.

in any case op your boat reminds me of a folkboat...I miss mine dearly! jajaja
 

·
Senior Moment Member
Joined
·
13,300 Posts
3/4" bulkheads would be excessive on a boat that size. 1/2" is plenty. Triple tabbing of 1708 biaxial would be super strong - double tabbing would be plenty good.

Don't fall into the amateurs trap of "a little stronger, a little beefier" - it's a fast way to a slow, overweight boat. You should always be looking for ways to lighten things up, not increase their weight & size.
 
  • Like
Reactions: Kielanders

·
Registered
Corsair 24
Joined
·
4,594 Posts
I agree, however not on things like bulkheads and chainplates...I would never say go undersize unless you are using materials that are known to be stronger

one thing thats very noticeable at least on the boats I have had is how little tabbing was done on the oroginal bulkheads in many cases leading to issues like ripped chain plates cracked ribbing etc...

it depends on who built your boat mostly but I can show you pics of my original tabbing on my boat and its like they used scotch tape to hold the bulkheads in place

so most owners are prudent in correcting that and improving the tabbing per se...

anywhoo

in general terms I agree completely the whole go big or go broke themes people do on boats sometimes does more harm than good other than as a placebo

this is especially true regarding rigging and standing rigging...

in any case 1/2 inch like above is a great size...I bet its what you had in there originally

peace
 
  • Like
Reactions: Kielanders

·
Senior Moment Member
Joined
·
13,300 Posts
Crazy idea - not even particularly cheap. Use epoxy coated ply and do a good job of tabbing it in.

For ribs, just use foam or PVC tube or even cardboard tube as formers and laminate glass over them.
 
  • Like
Reactions: Kielanders

·
Registered
Joined
·
144 Posts
Discussion Starter · #14 · (Edited)
Crazy idea - not even particularly cheap. Use epoxy coated ply and do a good job of tabbing it in.

For ribs, just use foam or PVC tube or even cardboard tube as formers and laminate glass over them.
Not looking for cheap, not looking for top of the line, was trying to think of something that will unquestionably last, and just enjoying considering the options and being a little creative.

Thanks for the thoughts on the ribs, the PVC is an excellent idea I hadn't thought of before.
 

·
Registered
Corsair 24
Joined
·
4,594 Posts
awesome stuff tommays

kielanders the pvc trick works well....however wood slats are the tradional method...
 

·
Over Hill Sailing Club
Joined
·
3,688 Posts
Think I'd probably find some dense foam like some polyisocyanurate insulation to form the substrate. I'd just shape it and stick it to the hull inner surface with some contact cement. Then you could glass it in immediately. Don't forget to feather the adjoining glass at a 12:1 ratio. If the glass is 1/4" thick, taper back approx. 3". The first glass layer needs to be the biggest pc.
 
  • Like
Reactions: SloopJonB

·
Senior Moment Member
Joined
·
13,300 Posts
Think I'd probably find some dense foam like some polyisocyanurate insulation to form the substrate. I'd just shape it and stick it to the hull inner surface with some contact cement. Then you could glass it in immediately. Don't forget to feather the adjoining glass at a 12:1 ratio. If the glass is 1/4" thick, taper back approx. 3". The first glass layer needs to be the biggest pc.
That's a very good way to go but shaping it can be labour intensive. Cutting PVC tube in 1/2 and tacking it in place with hot melt glue is quick & easy, Doesn't weigh anything really and the round shape is easy to glass over. It also holds screws when you fasten a wood ceiling over it - the glass alone is too thin to do it well and foam does nothing.
 

·
Over Hill Sailing Club
Joined
·
3,688 Posts
That's a very good way to go but shaping it can be labour intensive. Cutting PVC tube in 1/2 and tacking it in place with hot melt glue is quick & easy, Doesn't weigh anything really and the round shape is easy to glass over. It also holds screws when you fasten a wood ceiling over it - the glass alone is too thin to do it well and foam does nothing.
It doesn't look like the stringers and "ribs" are 1/2r. in the pix. They look somewhat rectangular but it's hard to tell. If they are, PVC tube would work fine if the right size. I thought some pipe insulation foam might also work if they were 1/2round. The size has got to pretty much on the money to make the layup come out matching. That's why I thought some insulation foam would work. It's easy to shape, unlike a styrofoam, but does make quite a dust mess. It would also bend to conform easier than pvc.
 

·
Registered
Joined
·
144 Posts
Discussion Starter · #20 ·
It doesn't look like the stringers and "ribs" are 1/2r. in the pix. They look somewhat rectangular but it's hard to tell. If they are, PVC tube would work fine if the right size. I thought some pipe insulation foam might also work if they were 1/2round. The size has got to pretty much on the money to make the layup come out matching. That's why I thought some insulation foam would work. It's easy to shape, unlike a styrofoam, but does make quite a dust mess. It would also bend to conform easier than pvc.
The 4 stringers (2 each side) do look rectangular, but up close when ground-out, they are about 2.5" wide x 3/4" thick, and either edge was chamfered at 45 degrees before glassing.

The foam type used on this boat was Divinycell, and appears to only have been used on these stringers and the coach roof. The stringers still in the boat do not appear to have been used for mounting hardware of any type from the factory.

My only internal debate with using foam (and I'd like to), is will it and the tabbing provide enough bite for the screws over the wear and tear of time. The foam would definitely be easier to place and conform to the hull for a professional looking install. The wood will be a bigger challenge.

Relief cuts in PVC (to get it to conform) seems like a tempting compromise, though I may want to pre drill to avoid cracking.
 
1 - 20 of 27 Posts
Top