CSC 30 Catamaran- the coastal passage

Discussion in 'Multihulls' started by peterchech, Nov 29, 2011.

  1. Gus7119
    Joined: Dec 2015
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    Gus7119 Senior Member

    Cheers mate. So 280 and you didnt habe to do anything except construct. Interesting it is alot more. There are cats from the 70s out of ply still 'plying' the oceans.
    As for materials other than hull. Here in Sydney like most states in Australia only about 60% of boats on moorings are used the rest sit till waterways takes them they sink or someone goes well Ive seen that boat sit there for 15yrs with not on visitor and take it. I already have my eyes on a few 30 to 35 foot monos whos rigging I know is in great shape that I can pick up for under 1000 so most deck gear will come second hand.
    Now the resale value. Not to gain sympathy or get points but as an explanation as to my thinking. I have spent the past 20yrs lookong after my family a kid with a chromosomal disorder and a wife with breast cancer that came back twice after initial diagnosis. So have spent most of this time in hospitals. So have spent every last sent on secondary care for them both. Therefore I dont have 3k to buy plans and while I'll build it properly need to save where I can. I have built one of these modified with a boat builder who died and its been in Asia for the past 5 or so years done a circumnavigation already.
    Hence why I am going with this build. And have no plans for selling the kids can deal with that or give me a viking funeral on the thing when I die. I have the skills and have been doing repairs and builds since my teens on boats from Manly juniors to 55ft stink boats so an happy to back myself.
    This forum has been a great resource and hence why if anyone has ideas mods or helpful hints Im open to then just wanted to clarify that it was going to be in ply and we go from there. Theres even a great guy who's built a model done some cad work and is working on cnc files.

    So I hope buy the end we can have a plan for a great sea going boat that we can say hey heres a free plan thats been built and tested and you may like to look at it. Or just for my build if not. But I can say that the very basic plan on coastal passages site thanks again Bob, does give enough info to get you going is you know some basics. But of course Id use an Australian designers plan if I could afford to but thats not an option. Just wish I had the plans we drew up for the one we built as the guy made them common licence after they were finished but I dont know the owner and the boat builders dead so dam.

    On last thing anyone got any experiance with the A frame mast it makes sense to me using a ferler on maim with a wishbone boom

    Hey thanks all for all this great input and discussion who would have thunk it a!
    Cheers gus

    Attached Files:

  2. redreuben
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    redreuben redreuben

  3. Gus7119
    Joined: Dec 2015
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    Gus7119 Senior Member

  4. groper
    Joined: Jun 2011
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    groper Senior Member

    Gus - its not as simple as you may think to calculate the costs...

    For example - when i say $280 per sheet - thats all it costs and you have something that is ready to paint, or ready to fair and paint if you dont get it fair in the first place. Both methods require the same amount of resin and glass to tape all the seams - which is also a significant amount of resin. Epoxy costs around $3500 per 280kg drum lot. Youll probably go through 2 of these building in ply. I used closer to 4 drums in total considering all my panels are glassed minimum 600gsm both sides - more than that in many other places. So theres 7 grand for you just in resin...probably 5 grand in ply, more money for stringers ?, then windows and hatches etc. I also used about 8x 20L drums of paint (edit - now i think about it its probably more like 10 drums), both undercoat and polyurethane topcoat... thats another $5 grand right there and doesnt include antifouling yet either... Then theres a bucket load of other stuff like micro spheres and cabosil, cotton flock for glues and fillets, rolls of glass and tapes, a million paint rollers and brushes, boggles the mind when i add it all up. You dont feel it so bad as the costs are spread over time... i reckon ive spent over $1000 in sandpaper too btw...

    With ply - you have to sheath it in glass, impregnate the ply with epoxy, glue the stuff together, scarf joints etc, and more liberal use of stringers, and being a natural product, your results will not be as fair as composite panels so youll spend more on fairing compounds etc to get it to the same level. Its a truck load of epoxy... And all this extra resin and other "stuff" drives up the price beyond what you may think. Like i said - my friend built his "easy 37" and it cost him $40k for the shell. My boat cost me $50k for the shell in full foam core but its probably just a tad smaller, but not by much worth talking about... We both have taken similar amounts of time to build them also... Dont get sucked into thinking you will build this for cheap - building boats in australia is expensive... if i could do it all over again - i wouldnt... not here anyway. I would consider going to thailand or the like, and paying an army of people to build it for me whilst i supervise it. Be done in 6 months and for less stress... Thats if i wanted to build again - from what ive seen locally - there is some real bargains around. Recently i saw a 15m Jim brown cat come down from PNG, all timber with alum rig. Had 2 brand new outboards but the rest of the boat was looking tired with virtually no interior fitout to speak of... The hull was sound, just needed freshening up, and the rigging redone, new sails etc I was offered it for $30k but my plate was already full... no way you get even half that boat just in materials alone these days and youd have a boat to sail from day one...
  5. Gus7119
    Joined: Dec 2015
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    Gus7119 Senior Member

    Thanks for the heads up. I have built a couple of boats and dont by any means underestimate the cost here. The Philippines is the place to build stuff there it is stupid cheap.
    The Resin is sorted as a mates dad has been working in the industry for 40 yrs or something he either makes it or imports it, never really taken much noticed, god I hear that and it sounds bad. but none the less hes giving me two drums for 1900 which I thought was good before but now see as great. The cloth I have from when I was doing repairs full time last look I have 2 rolls of 600 and i think a roll and a bit of 300. Sand paper got boxes of from when I left my building company, must say havent check it in many many years I assume its right as Ive used bits here and there. And for some reason my brother in law who I helped build his mono hull, get this its laid up glass and gota be about 2.5/3 incs thick in parts had 20kg of ballons left in kilo boxes. and the boxes are not small as its so lite.
    I am chuffed at your concern its really nice to see genuine people out there still. Id lost a little faith recently in that. But it is something Ive wanted to do for a long time and I figure secondhand rig, have made hatches before believe it or not out of Plexiglas and film and theyve worked really well.
    Ive been looking at the Waller designs hes a QLD guy and like them. I was thinking that the total cost of the ply your right is around 5k and then the stringers I can get them from D and R Henderson that a mate owns for like 10 cent a meter shame they dont do ply. They do partical board and Im not sure that would do so great on an ocean going vessel.
    By no means am I under any illusions that its easy nor cheap but Ill chip away weekly and get the hull done asap and then put it on a mooring and finish it of slowly so I have a setup Im happy with. I dont want to sound like an *** or come across arrogant because thats so far from the truth so please dont take that away from this post.
    Did I miss what you built? and what does the easy look like finished? I bet it wasnt easy to complete I always found that name a little perplexing.
  6. groper
    Joined: Jun 2011
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    groper Senior Member

    I designed my own cat - so i didnt buy plans either. I have a build thread in the "boatbuilding forum" probably should have gone in the "fiberglass and composite boatbuilding" forum but anyway... Theres a ton of photos in there which detail the entire process, heres a more recent pic;


    I chose to keep it as a power cat rather than a sailing cat. There were times i considered otherwise but this was what i wanted for now. Ive owned other sailing cats- i bought an oram 39C and fixed her up more recently - i think thats in the build thread too come to think of it... I figured a big sailing cat would be the next project i take on - ill muck about on this powercat whilst my kids are still young, then when im ready to take off and not have to come back - do the big sailing cat with the knowledge ive gained on this little powercat...

    Ok i understand your determination to build - i was no different :)

    Another thing which comes up from time to time - people selling unfinished boat builds... these can be had for the price of materials or less and you get a massive head start in the labour cost...
  7. isladelobos
    Joined: Jun 2014
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    isladelobos Junior Member

    I'm following your work some time ago, in both forums, you've done a good job with this cat, thanks for sharing.

    I'm testing the floating line LWL in the model, some days ago and make a short vídeo.

    I´ve put in the interior of the model two 1/2Kg weights, in total 1000grams that in 1:10 scale is 1000Kilograms.
    The test was in a not salted pool water.
    The floation line was perfect in line with this weight in these conditions.

  8. rob denney
    Joined: Feb 2005
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    rob denney Senior Member

    Gropers boat is 35' vs your 30'. His is designed for thick panels, yours for thin (more stringers, frames etc), his was built in a confined space so he could not build full length panels. Compared with what we know now vs then, he could have saved himself a lot of time and effort. An example is the infused 60' harryproa hull requiring no wet laminating, and no grinding or cutting cured laminate.

    To set the record straight, base costs for the 6mm ply vs 6mm foam/glass are:

    Infusion vinylester $7.50 per kg, polyester half as much, WEST twice as much.
    If the ply boat is coated with the WEST recommended 3 coats inside, it will use about 400 grammes per sq m inside and the same on the outside for a layer of 200 gsm cloth.
    The infused boat will use about the same to wet out a layer of 400 double bias inside and out.
    Some infusion resin will be in the plumbing, some WEST will be on the rollers, brushes, floor and applicator. How much depends on the operator and the set up.
    6mm ply marine gaboon ply costs $51.50 per sq m. 6mm foam (or balsa) $30/sqm.
    Infusion needs a pump ($150) and a table. Ply needs all the woodworking tools you already have.

    So, the extra glass on the infused boat is offset by the higher cost of the epoxy on the ply. The ply is more expensive than the foam. Tools and consumables favour ply. The cost overalll will be pretty similar.

    The ply boat builder will/should spend almost the entire build wearing gloves, suit and respirator, and a lot of time doing hard labour. The infuser will take less time, and almost none of it will involve dust or wet resin.

    Groper is right about the cost of building in Aus. However, if you design and build smart, it is possible to save a lot of money. For example, Bucket List ( is a 40' racer, with little accommodation but a very big rig. It costs $US50,000/$71,000, professionally built, in Aus, ready to race. A similar speed and space cat or tri would be a lot more. Similar savings apply to cruising versions.

    Re wishbone mast rigs. I have never used one, but they are obviously more windage and small section poles in compression need to be kept in column and/or be heavy and/or large diameter. Weight aloft increases pitching and reduces the point of no return in a capsize. Hoist a person half way up the mast on a choppy day to see the effect on pitching.
    Furling mains (and headsails) are fine when they work, but they only have to not do so once in a squall at 2 am with the sail part furled to really screw your trip.
    By far the easiest rig to use on a cruising boat is an unstayed mast, ideally in carbon (also much cheaper than you think), but in timber if you don't mind the extra weight, work and cost.

    Re honeycomb: There are 5 types. Alloy (should not be on boats due to electrolysis potential), nomex (light and waterproof, but expensive), phenolic impregnated paper (Tricell, sold by ATL as raw material of in panels, not waterproof), the paper stuff they use in household doors which you can impregnate with epoxy (waterproof but pretty heavy and messy to make) and Polycore, which is plastic with a scrim to glass to. Excellent product.
  9. gypsy28
    Joined: Mar 2010
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    gypsy28 Senior Member

    Im after some 6mm foam, who is your supplier at $30/sqm?

  10. rob denney
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    rob denney Senior Member

    ATL on the Gold Coast. Ask for Mick.
    If you are not local you may have to go through an agent and pay more. In which case, drop me a pm and we can sort something out.
  11. CT249
    Joined: May 2003
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    CT249 Senior Member

    Thing is that some get sick on cats, but not on monos, and cats can have serious motions in beam seas when one hull is on the crest and the other in the hollow. It's just that there is no one rule for everyone.

    Yep, spent two years living on a mono, and two one-year stints. It was probably roomier than a cat of equal cost. My family tends to have cats for cruising, but then again my wife (a cat racer) prefers monos for cruising. It's all whatever suits the individual taste and situation, as far as I can see.

    Good luck
  12. Steve W
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    Steve W Senior Member

    I have already made my pitch for infusing flat panels using vinylester or polyester and balsa core instead of epoxy /foam to build a boat which should be less expensive to build and have higher value when sold.Actually it shouldn't have higher resale value than a good plywood boat but most likely would, but I'm not going to harp on it as the op has made it clear that he wants to do ply. I do agree that it is easier to build in ply if you need to buy materials a little at a time. With composites you get the best pricing when buying materials in bulk and with infusion you really need to as the initial work
    building the panels goes so fast.
    Something to keep in mind on the cat vs mono motion comfort issue is that no matter who you are and how much time you spend aboard, you will spend most of your time at rest and nothing beats a cat for that. I personally don't care much for the jerky motion you get with bridgedeck cats in some conditions which i never noticed on my mac 36 cat or other flexibly mounted cats ive sailed on, but it is way better than constantly sailing on your ear.
  13. Gus7119
    Joined: Dec 2015
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    Gus7119 Senior Member

    Gee This has been so much better than I thought it woukd I have so many shout outs;

    groper mate love that boat looks great and an own design fantastic Im going to go look for you build. And cheers for everything else. As I cant read your post as I do reply if there arent links to your stuff could u post them I'd love to have a gander. Also its not a matter of not wanting to buy a boat. Its just cant afford it and can get large chunks of hardware monthly or weekly. Then you say you should save. Yep to right. But each time I ve done that it goes one someone or another medical costs this way I cqn chip away. I hope your here for the whole trial and tribulation and that we cqn raft up some time. And then Ill secretly put a mast and sail on your boat so your no longer a stink boater.

    isladelobos again your kicking goals and doing great things your supporthas been fantastic.

    rob denney thanks a heap for that brwak down it really was insightful. Qustion though viynl and poly shouldnt be used on the glassing of the hul right or wrong as it doesnt flex? But can be used internal. And westsystek is just a brand now isnt it? I know they created infussion ply but wouldnt use their products as far more expensive, yes or no?

    CT249 for talking sea sickness. Yep agree its subjective. Ill have to leave the wife in Australia and hope shes here on rwturn if she cant handle a cat its a last chance thing as she wont go near a mono after a few fun times I had her out in.

    Steve W cheers for info and understanding my reasoning. Id just buy one if I could but unfortunately that wont happen. And I to reckon a well built ply boat should go for as much but its seen a inferior which is a shame. Because I reckon if it was given more of a chance people would see they can be great boats. And yes unfortunately if I could but bulk itd be cheaper but I can't and am resigned to the fact. But happy!

    Really thanks and keep any secrets cheap prices ot more r ideas coming. I am starting the bulk heads the first day of Feb. So itll be my soil turning day.
    All the best
  14. Gus7119
    Joined: Dec 2015
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    Gus7119 Senior Member

    Is she flat bottomed? Went to you user account and dont seem to be able to find pics youve uploaded. O all my posts have been made via a phone hence the strange spelling and missing letters. Hope everyone can understand the posts as my fingers a little big for on screen keyvoard.
    As said above if possible please post links Ill search on my PC try find them in mean time.


  15. outside the box

    outside the box Previous Member

    It might pay to run this calculation, the below comes from a much larger professional design document regarding scaling and design models.

    JFWIW building a boat any boat is a per foot cost exercise no matter who designs it and the price of a good set of plans from a good designer is the smallest cost you will put into the boat. Many forget this. Resale is also a factor look at the many 1 off no name designed boats for sale even if very good boats, then look at a well known designers boat for sale of a similar boat and because we are talking small Ply sail cat here look at Richard Woods designs very reasonable cost for plans very active designer and when his designs come on the market if realistically priced and built to plan to a good standard they sell readily. Enjoy your build no matter how you go but think very carefully to what people on here are saying there are some very experienced people offering up good advice.

    To scale displacement take the scale ratio.
    Think of a ...16 foot rowing or sailing skiff. It might displace 360 pounds when occupied by one person. Let us build a model that is scaled to one and one half inches to the foot. That would be one eighth scale. so.....8 x 8x 8 = 512....divide....360/512 = 0.703 pounds. That is all the model could weigh in order to simulate the 16 footer. If you built the model to 3 inch to the foot scale then that would be a quarter scale or 4 to 1 model 4^3 = 64 .....360/64 = 5.625 pounds. The same rule applies when using the metric system of measurement.
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