easy, fast to build multihull with simple rig

if your building boats the same way as was "the norm" 20years ago, then you are living in the dark ages...

I chose to design and build my own boat, because i could see there was nothing out there that offered the design i wanted with an efficient build method. I researched a bunch of stuff over many months, and ended up designing my boat so that it could be built from infused flat panels - the same method Rob Denny uses. Why? Because it is the best way for 1 off home builds! I also incorporated a few areas with compound curves which will have to be foam strip planked or female molded so the boat looks elegant and not too boxy - despite the extra time its going to cost me.

I honestly dont think you will beat this construction method any other way, its very fast and its very light.

I use a fantastic spreadsheet i was gifted from another forum member which accounts for everything including every last drop of resin used in the infusion process (resin to fill the foam surface, resin in the perforations, resin in the peelply, resin in the flow media, resin in the feed lines, resin in the glass, everything...) The costs of each material and consumable is also inputted and also the weights.

From this, i can see exactly how much resin to mix for each panel i make and wastage is minimized. I know what each panel weighs and what it cost me to make it via a column for each method handlayed vs infused vs vacbagged. According to the spreadsheet, Infused panels are always the lightest, the difference in cost is negligible. Post infusion, they end up cheaper and even more lighter (deliberate grammar) because you dont need to fill and fair them - just take them directly to paint.

And building in timber? i dont know where you get your timber, but over here timber and good quality plywood is getting very expensive - structural foams are just as cheap if not cheaper, and they are easier to handle, cut, and shape aswell as being nice and perfectly flat (fair) and you end up with a lighter build with higher resale value.

Id love to hear a bit more about this Rob, would you please PM me if you do not wish to post here?

 

Yes I thought you might suggest Mr Kelsall for more conventional designs. Fair enough.

I may have missed something but I am not aware of Mr Hughes doing a lot of foam core ? I thought he was more into the cylinder molding thing ?

BTW my name is Damian, I post sometimes to the yahoo group. Just so you know who your addressing. Unfortunately I can't always aquire my real name on internet forums.

a 35' demountable cat would be nice 4' hulls....trailer...;->

Anyway, all good fun.

 

Costs

Rob-

You seem quite keen on this so here are some figures.

Mast and boom $800 (may need different boom)
Second Mast for crossbeam with some rigging $150
Sold half of second mast to another cat (400)

Huge roll biaxial maybe 140-160kg total $200
Timber for 2 hulls stingers bulkhead framing $400
125 yards 8.5 oz cloth $200
75 yards 3.16 oz for inner planking $200 can't remember for sure

60 sheets of ply $3200 will need 30 more?

4 Used Lewmar Hatches one needs lense replaced $300
6 Lewmar Portlights $300
New surplus Bomar Hatch front of cuddy $175
Harken 16 self tailer for main halyard w/handle $200
Bought 2 Lewmar 16s $150
Sold Lewmar 16s will get 30s (240)

50 gallons epoxy $3000

Fillers $150

SS Torx Screws $200

10 gallons epoxy barrier primer $300

Force 10 stove (gift) gas to pick up $60

Toliet and anchor roller (both like new) $80

Trailer to move mast/ launch boat $400

New/ surplus mainsail $800
have furling jib and spinnaker for previous boat

Bought steering wheel/ pedestal/ quadrant/ blocks
misc vang and mainsheet tackles/ boat dismantler $150
Sold some of above items (150)

25kg Bugel Anchor $110

18' Para-tec sea anchor $400

Anyhow, bust out your calculator. Sure there are a bunch more little items purchased over last few months. I was thinking of keeping better track, but why bother?
I have most chainplate materials 1x19 wire, turnbuckles, running rigging, etc.
Need to get some jib tracks (have cars) need mainsheet traveler.

Still using the same 1.5 inch "fooler" redtree brush for epoxy work I started with in December. Soak in vinegar when done then rinse in solvent prior to use.

 

Your american prices are MUCH lower than our prices in australia - on average, we pay double USA prices for goods in australia, - our wages are roughly double also, so it all balances out in the end - and its why shrewd boat builders import big ticket items such as diesel engines etc from over there...

average family car here runs $30-40k... and for a big F250 truck, chev silverado or dodge ram = +$100,000... no bull...

 

Gooday - 'groper' from up in FNQ - When we want some very good prices on Carbon-fiber & special materials we buy them in America & put them in a container that's coming out here & always has more spare room in it that we have money to buy goodies to fill the spaces with & all that cost very little in freight - so it's a win - win . Ciao, james

 

I have lived in NZ and traveled in Australia. Keep in mind most of the prices cited are VERY low even for the US. I had considered building a boat in NZ, but figured it would cost me at least 3x as much.

Not sure your wages are entirely 2x higher in Oz. Maybe in certain sectors and wages in the US vary widely by region. I'm a marine engineer so would be curious to know what one might make in say Sydney or Brisbane. Where I live in at the moment probably pays some of the lowest wages in the country for marine work, but I'm mainly working on building my boat.

Plan to move/cruise to one of these high wage/ high cost places when my kids need high school and college and get to work!

Cheers,
Jeff

 

thanks for the infor

Mr. Denney,
I just want to thank you for your informative posts. I think you offer very practical advise for those of use who are on the fence and watching what others are doing. Great work, and very inspirational.

 

Well said and ditto

 

FWIW I'm a mechanical engineer working as a design draftsman in Brisbane. Government pays 60-120kAU private probabaly add 10-20% over that.

Engineers a bit more depending on what your doing. It varies a lot. Some people for some reason stick with employers that treat them badly and pay a pitance.

I'm not 100% sure what you mean by "marine engineer" since everyone from salesmen to academics like to tag engineer onto their job titles these days. If you do hands on work on ships and boats then wages are pitiful. If you do design, investigation, "professional engineer" stuff I suppose wages would be better but the marine industry generally doesn't seem to pay well, like the aircraft and car industry. If you have a recognised degree and are prepared to work in mining, petroleum, project managment that sort of thing the potential is a lot higher. Western Australia is the place to be as even here in the "other mining state" we're in a bit of a pickle economically.

Engineering salaries in NZ seem to be about 60% what you get in the cities in aus but that's my eyeball average not hard data.

 

No problems posting here. The bulkhead landings are made of 25mm foam cut into a right angle triangle with one corner rounded. They are hot melt glued to the panel (or mould). Distance between them is the bulkhead thickness plus glass and peel ply. The laminate is laid up over them and peel plied. Takes a bit of practice to get the size right and the glass into the slot, but it is worth it in terms of labour saved. The first time it is probably best to stop the main glass either side and lay a strip into the landing. It does not work on areas that are going to be bent, so these still need filletting which is hard work on narrow hulls. This is one of the reasons the current crop of narrow hulls are built in mdf moulds.

The male/female joins are pretty simple. A rebate (1mm plastic strip) on the outside of the male, the core of the male reduced by the total skin thickness, plus a little and a spacer (foam wrapped in plastic and peel ply) in the female. Remove the spacer and the peel ply and glue them together. Works best on flat surfaces as it is stiffer than the rest of the laminate.

Any other questions, please ask. Had a look at your posts on your boat. Looks good. Where abouts are you? Be nice to have a lok at the real thing if you are in SEQ.

Boatguy,
Thanks for the costs. You definitely got some bargains.

Guzzis3/Damian,
Kurt has been doing foam boats for a while, and is now getting into panel boats. CM is not so popular now as the cheap ply is apparently not available, but it was a good way to build ply boats when it was. I suspect a CM foam hull is on his to do list. Kurt is a big fan of unstayed rigs, reckons they are the way of the future for USCG certified boats due to the lack of maintenance required.

"a 35' demountable cat would be nice 4' hulls....trailer...;->:
I was involved with one of these a few years back. 4' wide (3'6" in reality for 8' traillering) hulls are not much fun to live in and the dramas of getting all the bits apart and onto the trailer and putting it together meant the boat rarely ended up being trailered. And then along came Cat-2-Fold..... Not sure I could improve much on this, although there are probably easier ways to build it.

rob

 

Sorry mate, im up in FNQ where the rainforest meets the reef If your ever up this way, be great to meet you for sure...

Ive already been doing rebated edges on my flat panels, just use some 2mm HDPE strips 100mm wide and place them down on the table and do the layup on top. Seems to work great although need to be careful of a good fit or resin racetracking occurs on the bottom side. Should allow taping the panels together with no fairing beyond the join itself.

Another thing im curious about, is mow much curvature can be tortured into a panel. I noticed the bow sections of your proas windward hull still have some strip planking where it transitions upward and inward at the very ends. I wonder why you have not incorporated kelsalls bending method with the dart cuts to get this shape? Another option would be a cone laying on its side and cut in half - which is completely develop-able / single curve... i resorted to a temporary female mold which i could use for both hulls;

 

Hey there 'grop' - I'm watching (with great respect) over your shoulder - sso to speak - from just up the hill - behind you. I'm impressed at your KISS - attitude & progress. Keep it going - sure wish I could see it in the flesh. Good-on-yea-mate. Ciao, james PS. I know that 'sailor305' is watching & learning - every move you make. Oh & thnaks Rob - Michael really regards you very highly. Ciao, james

 

Hi Boatguy. Are these the current prices for glass-fibre in the States?
Cheers.

 

yeah i thought the same thing... 150kg of biax e-glass would cost me over $1000 - even when i ordered +400kgs of the stuff... sounds like BS or hes got friends in high places...

 

Very interesting approach Groper. I'm not too far from Cairns an'd love to see it in real life.
You could also be interested in seeing my workshop and the boat construction experiments I'm up to.
Cheers Raf