Interior refit 1970's kit sailboat questions

[wingless]

Originally Posted by wingless

Cold weather not an issue in southern Florida...

Did my decades of snow shoveling. It is nice not being cold.

We had a "cold" snap, w/ temperatures this morning in the low 60s.

Everyone is dressed like Eskimos.

[Spot]

LOL -60's-that is sunbathing weather here. 8 degrees F here this morning. Sunny and 34 F now.

[GILow]

Spot,

Congratulations on a great project and some promising progress so far. Please take the following comments in the spirit in which they are offered, which is hoping to help you avoid future problems.

Looking at the photos of the work so far, I really feel you would benefit from finding a good book on interior fitouts. There is no doubt you have the manual and technical skills to carry out the work, but you are missing a lot of theory, and I fear it may cause you some problems.

For instance, those forward cross supports that you remarked would have been easier to install if there had been a beam shelf, are a potential problem. They are rigid compression struts, tapered so that any downward force will push outwards on the hull. So any heavy load that causes movement in the forward settee will push outwards on the hull. Also, as the hull oil-cans into any heavy seas, they will not yield, whereas the hull around them will. You will almost certainly develop crazing in the gelcoat at these points. The beam shelf would not only have made installing the settee easier, it would have also allowed a small gap at either end of the cross beams freeing the hull to flex more evenly. Tabbing in the top of the settee may prevent problems, but I'd be worried.

Likewise, the circular hatches are great, but they've left very little support material around the hatch in the original structural material and I suspect you've already discovered this is a problem. I can't remember where I read it, but I work on around at least 30% of my original panel span remaining after the cutout to keep things strong. This leads to the kind of odd shaped hatches you see in boats, in the case of the settee they would have been triangles with large radius corners. but you'd have had good openings with much more support remaining.

This is all offered as free advice, and therefore you can determine the value yourself. But at the tail end of a two year, bare-hull fitout, I have been endlessly grateful to my copy of Ferenc Mate's "From a Bare Hull" for all the little bits of wisdom I have gleaned and the potential problems I have avoided as a result.

Matt

[Spot]

Hi Matt-
Thanks for having a look at my project and for taking the time to write down your thoughts. I leafed through my copy of Maté's book after reading your post. I see your point about the ends of the cross members under the v-berth making a 'hard spot'.

Short of tearing everything out and starting over ala Maté with HD foam under glassed stringers, beam shelves, and tabbed bulkheads...Is there anything else to do to improve against these concerns? I really wish I had the original assembly instructions from the kit, most of what I did was a reorganized replacement of what was there, straightening out the 50mm error in the v-berth (starboard aft was 50mm off the laser line, rest was more or less plumb) while making the Porta-Potti more accessible (no more cross beam in front of the head). I could possibly see adding a couple floors and then have struts from the floors to the beams and then cutting the beams at the tabbing to remove the hard points and making it all like a horizontal bulkhead.

[GILow]

Spot, I feel like the way you have tabbed in the tops of the settee should reduce the risk of problems.

Perhaps, at the first opportunity in a decent sea state, you could get someone else to grab the tiller and get down the front with a torch and just watch what is happening. The load may be well enough diffused by the settee top that there is no real problem. And likewise, just be mindful that nobody tosses anything heavy onto the settee that might induce a shock load. (And... Er... maybe be careful what sort of extra-curricular activities take place up there too...)

Not the end of the world, and I didn’t want to rain on your parade, just something else to consider with the rest of the fitout.

Incidentally, I totally liked your philosophy of trying to work with materials that are readily available from mainstream hardware stores.

I got mercilessly patronised for using construction grade plywood in my boat build, rather than marine ply. I simply cannot get people to understand that:

a) I cannot afford to be a purist about this stuff, I’m a student and this is my home.

b) if I need marine plywood for my boat interior then I have a much more serious problem than aesthetics, the boat must have sunk.

Not sure if you’ve seen any of the videos by Sailing Uma? I’m not fan of the whole bikini-girl pitch they use in their videos but I am very much a fan of their application of non-traditional materials, particularly at the aesthetic level.

Looking forward to the next progress photos.

Matt

[coopec43]

Originally Posted by GILow

Spot, I feel like the way you have tabbed in the tops of the settee should reduce the risk of problems.

Perhaps, at the first opportunity in a decent sea state, you could get someone else to grab the tiller and get down the front with a torch and just watch what is happening. The load may be well enough diffused by the settee top that there is no real problem. And likewise, just be mindful that nobody tosses anything heavy onto the settee that might induce a shock load. (And... Er... maybe be careful what sort of extra-curricular activities take place up there too...)

Not the end of the world, and I didn’t want to rain on your parade, just something else to consider with the rest of the fitout.

Incidentally, I totally liked your philosophy of trying to work with materials that are readily available from mainstream hardware stores.

I got mercilessly patronised for using construction grade plywood in my boat build, rather than marine ply. I simply cannot get people to understand that:

a) I cannot afford to be a purist about this stuff, I’m a student and this is my home.

b) if I need marine plywood for my boat interior then I have a much more serious problem than aesthetics, the boat must have sunk.

Not sure if you’ve seen any of the videos by Sailing Uma? I’m not fan of the whole bikini-girl pitch they use in their videos but I am very much a fan of their application of non-traditional materials, particularly at the aesthetic level.

Looking forward to the next progress photos.

MattAttachment 228214

I bought a sheet of ply from Bunnings today for a bulkhead (non structural) in the aft cabin. I had a choice of two:

• Marine ply $89
• Structural ply $72.

I chose the structural ply

[GILow]

Originally Posted by coopec43

I bought a sheet of ply from Bunnings today for a bulkhead (non structural) in the aft cabin. I had a choice of two:

• Marine ply $89
• Structural ply $72.

I chose the structural ply

At that price difference it might be worth it, but I see 12mm structural for $60 in CD grade.

But geez, 12 mm is pretty thin.

[coopec43]

Originally Posted by GILow

At that price difference it might be worth it, but I see 12mm structural for $60 in CD grade.

But geez, 12 mm is pretty thin.

It was 15mm 2.4m x 1.2m. I did deliberate but it is just a wall of the toilet. Marine grade would have been an overkill

[GILow]

Originally Posted by coopec43

It was 15mm 2.4m x 1.2m. I did deliberate but it is just a wall of the toilet. Marine grade would have been an overkill

Ah, not exactly comparing apples with apples there. The price for the marine ply you quoted was for the 12 mm I think. A lot thinner.

I agree 15 mm is good for lightweight non structural stuff, but I did use 19 mm for any bulkheads. (None of my bulkheads are structural). I found the 15 mm wasn’t quite rigid enough for big areas.

[coopec43]

Originally Posted by GILow

Ah, not exactly comparing apples with apples there. The price for the marine ply you quoted was for the 12 mm I think. A lot thinner.

I agree 15 mm is good for lightweight non structural stuff, but I did use 19 mm for any bulkheads. (None of my bulkheads are structural). I found the 15 mm wasn’t quite rigid enough for big areas.

I can't see Bunnings Marine Ply 15mm listed but when I was in their Mindarie Center today I am sure it was $89.

The ply I want isn't a big area - maybe 1.5m wide. (I used 19mm for the main structural bulkheads)

(I'm using Treated pine H3 where I need heavier timber for under beds etc - cheap, strong and light)

[GILow]

Originally Posted by coopec43

I can't see Bunnings Marine Ply 15mm listed but when I was in their Mindarie Center today I am sure it was $89.

The ply I want isn't a big area - maybe 1.5m wide. (I used 19mm for the main structural bulkheads)

(I'm using Treated pine H3 where I need heavier timber for under beds etc - cheap, strong and light)

$89 is the price for their 12 mm standard sheet.

[Spot]

Matt, Coop-
Thanks for the replies.

In 'Murica marine 1/2" (12mm) is 62 USD at my lumber yard with various other exterior grades from 20-30-35-40$ depending on face grade. I happened into a really nice batch from Chile that was 25$ a sheet, 5 ply, nice faces, and I used that to replace a 3 or 4 ply 3/8" (9mm) that was there before and had only been finished on the sides that show. I am painting everything and pre-painting whenever possible. My stick framing is 'select' (highest quality) stuff from NZ of all places as it is such a treat to use. I started in on using it on my last boat and will not go back to cheap dimensional lumber for projects unless unavoidable. So I have a little 'down under' in my boat...

Good tips on observing the joins and hull at sea and shock loads and such in the v-berth. The headroom is minimal in this boat so I do not anticipate much activity forward but who am I to say...? The worst undistributed load will be when a person sits on the edge of the berth to begin the climbing-in process and there is a leg or strut going down to a piece of ply on top of the inner hull at those locations.

[Spot]

PS- I have seen episodes of Sailing Uma and have had a quick conversation with them via email. I have also seen episodes and emailed MJ Sailing. Both were helpful with their email replies even though I am not a Patreon. If I had to have a short list they'd both make the cut.

[coopec43]

Originally Posted by GILow

$89 is the price for their 12 mm standard sheet.

Looks as though I am mistaken then. (It did seem a low price for 15mm Marine ply)

[GILow]

Originally Posted by Spot

Matt, Coop-
Thanks for the replies.

In 'Murica marine 1/2" (12mm) is 62 USD at my lumber yard with various other exterior grades from 20-30-35-40$ depending on face grade. I happened into a really nice batch from Chile that was 25$ a sheet, 5 ply, nice faces, and I used that to replace a 3 or 4 ply 3/8" (9mm) that was there before and had only been finished on the sides that show. I am painting everything and pre-painting whenever possible. My stick framing is 'select' (highest quality) stuff from NZ of all places as it is such a treat to use. I started in on using it on my last boat and will not go back to cheap dimensional lumber for projects unless unavoidable. So I have a little 'down under' in my boat...

Good tips on observing the joins and hull at sea and shock loads and such in the v-berth. The headroom is minimal in this boat so I do not anticipate much activity forward but who am I to say...? The worst undistributed load will be when a person sits on the edge of the berth to begin the climbing-in process and there is a leg or strut going down to a piece of ply on top of the inner hull at those locations.

Ooooh... NZ timber.! Now I am jealous. I do have a little bit of “Tasmanian Oak” for my fiddles and various trims, but apparently that’s a generic name for some kind of gum tree, so I don’t actually know what it is or where it came from.

When I was replacing the decks I needed 28 sheets of 16 mm ply. The best price by far was from a place in Melbourne, 700 km away.

As luck would have it, I was due a visit to the family in Melbourne, so I drove my van over to visit them, and came back with a full load. Driving the van over empty was, frankly, terrifying, but it was lovely coming back with half a ton of plywood holding it to the road.

The savings on the ply paid for the fuel for the trip three or four times over.

Matt