Catamaran plans, who have I forgotten ?

I discussed this with Mr Woods. He said you can just make the hull sides higher. I'm 5'6" the boss is 5'2". 5'6" headroom isn't a must but being able to stand up while cooking or pulling on trousers is a nice luxury..

600kg I was willing to cope with for the sake of trailering. If the boat is on a mooring it would be nice not to have to make that concession.

Yes precisely. The big problem with some boats is the mast is stepped so far aft it's hard to get the cabin in with clear spans for the bed. There was a Crowther advertised recently which had had a cuddy added. There was a huge notch in the front to allow the mast so they had offset the bed to starboard. It didn't look like a big mattress. Full length but narrow. If something like that came up at the right price I'd move the mast forward and rerig it. A lot of work.

There are very few boats here with cuddy cabins that come up for sale. There are more open deck boats and they tend to have lower asking prices than full bridgedeck cabin boats.

He adds and removes boats from time to time. He takes them off when there is no interest. Sagitta is the same hull but with a full bridgeck cabin. There was at one time another variant with a higher bridgedeck cabin with standing headroom. I don't know if any were ever built. He later drew Eclipse so...

Javelin isn't of interest to me. It's really a racing boat with daggerboards.

Windsong has a 500kg payload. It will fit a cuddy without moving the mast. I think it's a beautiful boat and would even put up with the pitching but it just isn't a load carrier. He was suggesting solid glass hulls a long time ago and hasn't updated those pages. Mr Woods now suggests foam and that is how I'd build it. The boat I really love in that line is Mira but it's just a bit too big. Love the layout and it's a real load carrier.

Yes I am well aware of all that. Given my health there is more than a passing chance I might die before finishing it. The question then is do I bother trying to do anything or should I just sit around and wait to kick off ?

All these boats I am looking at are similar size, no 40 footers. Yes a V hull is probably quicker than chined which is probably quicker than rounded, but you are talking about 1/10th the hull skin. Bulkheads, internal furniture, decks, cuddy, rig, fitout etc are all the same. Eclipse has been built with solid glass to the chine but Mr Woods has said it was very heavy hence he doesn't favour it now. If I strip in foam horizontally I feel ok with that, it's the vertical strip foam that scares me.

As I say once the hulls and beams are built I am on familiar ground so I know what I'm getting into there and am comfortable with that. My worry is the bit I have not done, and the bit that can't be reversed...

Thank you for the thoughts.

 

If you like the basic Windsong there are a few basic hacks you could consider.
Add or widen the keel panel so it’s a little dory like for more displacement.
Lay up panels without internal layup to pull a bit of curve into the sides.
Don’t go solid below the waterline use corematt.
Pitching. Plumb the bow and widen transom a bit more. Or my personal favourite Wharram hack, mount horizontal foils on rudder Skeg.

 

All good ideas but really is the inconvenience of building rounded hull bottoms that big an issue that it's worth re-engineering that boat ?

As far as I can see I can put the Saturn cuddy and rig on Scorpio hulls, build the dinette into the hull next to the galley, head in the other and I've got everything I want. No re-engineering, no radical mods. I can just get on with it ?

 

Saturn Cuddy on Scorpio hulls would be a great boat.
The rounded hull bottoms aren’t a big issue but you’ve repeatedly said how fearful you are of vertical strips.
Which I think is unfounded.
You will have far more trouble with horizontal.

 

You think ? The chines might show but at least they run bow to stern. If there are any bulges or dips in vertical that'd be hideous. Also there is the heat bending. The pvc foam I can get cheap is rigid. It will bend fore and aft but not enough for vertical. It would need to be heated.

I've even thought about gritting my teeth and paying for strip to the chine, pawlonia, and foam above that. It'd be faster and easier but the money...

 

Yes I think.
How thick is your foam 10-12mm maybe 15 ? How far is that going to span ? So how many frames are you going to have to set up to keep that fair.
12x50mm strips x 9metres that’s going to be a handling nightmare and then you have to glue it.
With what a filled epoxy ? So going around a curve hull the gap is going to be
significant, so every 40-50 mm a strip of epoxy to sand and foam between. Sanding that will end up like a motocross track. With only 12mm to soak up errors.
Vertical
Yes you’ll need a hotbox but with the battens running fore and aft you have a robust shape to fix to, far tighter gaps and much wider planks that you won’t have to join to make the length.

 

An avenue I would consider is making a batten mould for just the bilge and covering it with doping fabric like an aircraft fuselage.
Over that you could lay up a pair of stitched fabric and coremat bilges which you then join to your foam sandwich sides.
Or you could lay up one skin and then use contour foam. The sheets with cut squares glued to a scrim.

 

Good ideas. I was going to strip over the molds in thin ply and fix the foam over that to stop foam sagging between the molds.

According to the mat list there are 30 sqm below the knuckle, that's both hulls. Maybe I should just grit my teeth and get strip. It'll cost about $1500 but the saved aggravation....

 

Yes, you can always modify things, but again, doing so has the potential to eat up a lot of time. Essentially, you're going to spend a lot of time thinking about how to do things, and if you modify the boat it will make the issue much worse. Additionally, modifying things always has the potential to create unintended consequences (Just ask Fallguy).

Again, that's just to DWL. Doesn't mean the boat can't handle more and still perform well. Regarding displacement of small cats, Richard said elsewhere "Figures don't matter, what does is that a boat does 'what it says on the tin.'" If Richard says it's suitable for offshore voyaging, then it should be more than suitable for extended coastal cruising for two. That goes for Gypsy as well, which I assume you are not considering due to load carrying ability?

You're right, better to do it in foam. I think in the FAQ he says something like making the solid glass panels with stringers bonded is a pain and it's easier to just do glass/foam. But he doesn't say don't do it or anything like that.

Yes, best to get started, but that's really beside the point. The point was it's easy to burden yourself with extra unnecessary work.

 

Seems like Windsong but with a dory hull would be an attractive simple/spartan ocean cruiser. Or perhaps a 30ft Eagle with a bloated hull. I'm guessing Richard thinks Gypsy is the replacement, but that has what looks to be lower volume hulls and a cuddy, which means more work. Of course what do I know?

 

How cheap is that foam anyway? 30sqm of foam plus 30sqm of plywood plus the battens to support the ply is how much less then 1500$?

30sqm of 12mm battens is 0.36 cubic meters of wood, add 50% waste to produce said battens and we are talking half a cubic meter of wood. You can choose between paulownia, cypress (macrocarpa) and surian, all should be cheaper then western red cedar. Call Britton Timbers in Narangba and get some quotes for macrocarpa and surian.

 

Thank you for the comments. I don't know how to multi quote so I'll do my best. I hope this is clear.

Windsong/Gypsy/Scorpio.

Gypsy has a rated load of 600 kg. It can be built with dory hulls or rounded. Trying to make Windsong into a dory is a tricky modification and you are essentially building a Gypsy. Windsong is 2' longer due to the bow.

Yes they can all be overloaded but at what cost ?

You could even go that way with Skua. Another boat I love it is very slim on the waterline but the sides can be made higher for 6' headroom and it can be immersed deeper, given a hard deck etc. It ends up being almost a V hull but with a rounded bilge. Might hobbyhorse less than Windsong ?

You can disappear down all sorts of rabbit holes getting this boat or that to work. I am trying to find a solution that requires as little and as simple mods as possible. Scorpio is a different compromise. It requires Mods on deck and of course building those round bilges.

Regarding the cost of strip vs foam: I have already collected a lot of sheets with cosmetic damage so that doesn't add cost. The equivalent foam is about $500-600 from memory so there is about $1000 in it plus actually buying the stuff. I looked for the spreadsheet I did the strip calcs on but can't find it atm so this is from memory. Per square meter it's about 3x the price of foam. It's painful to do a whole boat but I can grit my teeth for the bilges. The whole hull cost is about $10k so it adds about 10%.

 

If 30sqm of 12mm foam are 600$ landed at your door, it means they sell it for less then 1000 US$ per cubic meter, wich is amazing to say the least.

 

The last price I got on 12mm, which was a couple of years ago, was $15US square meter. That included shipping to Brisbane but not port charges etc. Some of those are fixed so it's hard to allocate them proportionally across an order. It works out about $25AU sqm including taxes etc but not fixed costs per shipment. Depends on exchange rate etc.

Really rough estimate for epoxy, foam, glass, bagging, strip etc is about $12kAU. About $1000 of that is the added cost of strip. I'd need to get up to date quotes to harden up the number. If my epoxy is still ok I've already spent about $2500 of that. I'll say it again for emphasis, prices may have changed due to whatever random excuse you want, covid, Ukraine, day ending in Y, phase of the moon.

Does not include paint, rig, fitout etc etc.

 

@waterbear

Despite it being an honor to be named in full; many of us on the forum are trying to avoid identity phishing, so refrain from using my full name. I am sort of lucky that my name is also common language as searching for me is not easy; others less so. Anyhow, scratch the last name if you edit the post. Yeah, I know my nick..

Further, my modifications to the design are not the primary cause of my current frustrations. I've done all the math and there is nothing I could have done to make things correct. The proof of this is my forward lockers, in the current arrangement and hull design, would be fully unusable as they are not capable of holding anything without trim consequences. The boat is not capable of an anchor and roller on a pulpit either in the current state. The incremental contributions to vessel weight forward include using tempered glass to make better quality windows that open. A couple hatch doors could be reduced with great effort to much lighter carbon version at great effort and expense. The netting beam is 1/4" wall and should be 1/8" wall which is 20 pounds that changes the CoG 0.415" from memory (I ordered the wrong wall, got it polished and anodized, so several hundred dollars into this one). Given this matter has existed in 3 others in the design must also be noted. The real issue is there is not much reserve or none in axebows. So they tolerate zero weight delta and carry zero reserve. But I'm still a fan of the design; just needs some work. The idea a person cannot add a bow hook with backing plate that weighs 3 pounds is not much modification, but apparently too much even with an additional offsetting engine moment of 121 pounds•same feet. The roofspace atop the cabin currently has 106 pounds of solar that are forward of COG and removing them has incremental changes to the CoG, but major affect on trim. Simply put, the boat cannot tolerate any weight forward...this is not about me making changes.

I could go on about the matter, but understand, root cause is the hulls. I am sure of two other builders of the vessel who have experienced the same.