Bulkheads

[Bill A]

Tim,
What are your plans for finishing the bulkheads on the Daysailor? Varnished Meranti? A veneer? Or something else.
-Bill

[Tim]

The interior bulkheads are already covered in white-painted beadboard, which eventually will be highlighted with additional varnished mahogany trim. The small sections of the chainplate bulkhead that face the v-berth are also covered in this white-painted bead. (I don't seem to have a picture of those portions handy.)



The exterior of the bulkhead facing the cockpit will receive raised panels of varnished mahogany. That comes later.

[Bill A]

I see. I remember reading about the beadboard, I didn't realize it was going to cover most of the bulkheads. Combined with the varnished wood it's a very nice, rich look.
-Bill

[Rachel]

Hi Tim,

I hope I'm not asking something that would be plainly obvious if I went to the daysailor site, but, OTOH, it does fit in here...

I'd like to know what type of product your beadboard is. If I understand correctly, it is a more-or-less cosmetic facing to the structural bulkhead. Have you used actual wooden bead-edged boards? Or a panel product?

I really like the look - crisp white panels with nice definition and shadow lines, accented by varnished wood. Bright and woody at the same time.

That rounded cabin-nose is fantastic.

Thanks --- Rachel

[dasein668]

He used an interior-grade fir beaded plywood. It's the same stuff I used on my bulkheads during last year's head renovations. It's definitely NOT structural in any way, and is in fact pretty chintzy. But it's perfectly suitable as a cosmetic veneer. The stuff is about 3/8 inch thick, plus or minus.

There is a higher quality product available as well?a birch beaded ply. Quite a bit more pricey though, but definitely nicer all around.

[dasein668]

The exterior of the bulkhead facing the cockpit will receive raised panels of varnished mahogany. That comes later.

I'm glad to see that you've finally resigned yourself to the fact that those panels MUST happen.

hehe

[Tim]

I hope I'm not asking something that would be plainly obvious if I went to the daysailor site...

Well, I think it actually is pretty clear on the site, but that's OK!

It's a standard fir beaded plywood, 11/32" in thickness. It is not a fine structural product, and I myself would choose to upgrade and use a birch equivalent the next time. Frankly, the quality of the plywood (intended for homeowner use) is so bad that I find it to be a little embarrasing. It sure justifies the added cost of using good quality marine plywood for the structural elements.

For strictly cosmetic use, the fir bead is OK, though. With some effort, it paints up pretty nicely--usually 4-5 coats (including primer) are required. The birch product would be even nicer. And of course one could use solid wood, but the panels are more convenient, especially for overheads (I also used the same product for the down-facing layer of the decks and the cabin trunk overhead).

Here's a sneak preview of what's coming up on Sunday's Daysailor update. This is the new cabin trunk overhead, inside layer, which soon will be covered with more epoxy, meranti, and fiberglass on the outside. (And before anyone asks, yes: the visible centerline seam will be covered in trim!)

[Rachel]

Thanks Tim and Nathan for the bead-board info.

I guess I'll have to hie myself over to that daysailor site! I hadn't checked it out since I'm not really a "daysailor" type, but obviously that was a mistake :-)

--- Rachel

[mishnish]

Having spent 4 years infront of lecturers and whiteboards with another 2 to go trying to learn the maths and engineering behind small craft, nothing has given me such a clear and practical education in nuts and bolts boat building as your wonderfully documented work tim! As a result my Naval Architecture student house (5 guys!) stays in on sundays now eagerly waiting for your updates.... whats the big idea - are you trying to start a cult?!

We are all wishing you the best of luck with the daysailor, but we all have one nagging question... !!Weight Calculation!! what are your plans for making sure she floats at the right trim? you seem to have kept the whole vessel relatively symmetrical so far so heel shouldnt be an issue untill you start uneven loadings, but what about fore and aft? What were your thoughts on this when you started?

thanks for a great weekly read!

Chris Dowie
small craft student
university of newcastle upon tyne
england

[Tim]

The seat of my pants is well worn at this point.

One thing I have tried to do is keep major weights as central as possible, and also relatively close to the locations found in the original boat. I have made no calculations in this regard, and all I can do, frankly, is hope that she floats in approximately the right trim.

I see no way around an early test launch to see how she floats. Only after this can I determine whether any trimming will be necessary, and, just as importantly, determine where the actual waterline is so that I can paint striping and antifouling correctly.

One thing about Tritons in general is that they do not float properly according to their originally designed waterlines. I have yet to see one that was painted as original and not improperly trimmed, generally down by the stern. Part of this is because the boats all ended up significantely heavier than the calculated design displacement, to the tune of 1500 lb. (See this thread for the documentation.)

I feel the mass of the deck and interior structure on the Daysailor is rather well balanced against the mass of the cockpit structure and after quarters, at least as far as my pants tell me.

As naval architecture students, you're probably all cringing. This is certainly an area where I know I have no idea...but also feel that my overall boating experience over the past decades is coming into play to help me keep things on an even keel. I am prepared to add small amounts of trim ballast if necessary to correct the trim, something which is common enough even in engineered boats.

If I end up being wrong and the boat floats head down by 2 feet, I'll be the first to admit my mistakes. But I doubt that will happen, even if I don't know exactly where she will float.

Thanks for staying tuned in!

[mishnish]

Ha! We're not cringing at all tim! We would be if you were trying to wing it on some huge 50ft project with tanks and bulkheads all over the place, but I can see that what goes into a hull of this size is relatively easy to keep tabs on, and with your experience of this type of boat its clear that the end result won't be rediculous.

Reasons that i have confidence:

The daysailor now has a much lower slung profile than the original triton, so as long as you get the boat to float at roughly the DWL of the old triton, your Vertical Centre of Gravity (VCG) will be lower than the original, making the vessel slightly stiffer and safe in terms of transverse stability.

Major weights are what make the difference. keeping the engine in the same location as the original is a good idea. The fuel tank positioning can be useful too, but since it drains it has to be kept near the centre of bouyancy so that it dosen't cause uneven trim but there is scope to move this forward or aft to correct longitudinal trim issues.

Im sure you have already thought about this! Personally i hate doing weight calculations. For our group project last year we designed a 110ft sail training vessel. It took 4 weeks of pretty solid excel bashing and moving stuff around inside to get it to float on our DWL, needless to say coffee was involved in no good measure. Thinking about it though, owing to the fairly manageable volumes of material that goes into the daysailor it would be possible to set up a simple spreadsheet that will let you know if she will trim fore and aft or side to side, all you need is a good idea where the centre of bouyancy is. is there any info on that for the triton hull?

waffle I have done. cant wait to see the test flotage mind you!

[mishnish]

PS...

when she floats on an even keel (and she will!) you will have done a better job than the large design office at Bavaria, whose Bavaria 32 trims to starboard by an alarming 2 degrees! They fluffed up the position of the water tank or something! she does particularly well on that tack!

[Figment]

The beadboard and brightwood combo is really looking fantastic, Tim. Nathan's head renovation had me 90% convinced that I'd follow suit (you know.... once I start interior projects.... someday.... somehow) but now I'm 100% sold on it.

The look has all the richness and depth of the true-paneled bulkhead at what appears to be a small fraction of the labor.

[Figment]

Fantastic.

[Tim]

Thanks! I'm pretty pleased with how it's coming out. It'll be even better, hopefully, as I get the rest of the trim installed and varnished.