What are the plans for?

It is a one up design, which is what I was planning on doing anyways but I was approached by a naval architec that offered to sell me plans that he had worked on and planned to build himself.

I like this idea because I will still have a boat that is unique but someone with knowledge has had input into the design. Which is better than what I was planning.

Didn't you design you boat?

Yeah it's my own design.

A bit of caution with ppl calling themselves naval architects, they may not be engineers. There are a number of courses around the world that give naval architecture qualifications which aren't necessarily engineering degrees. There is a difference.

They may be perfectly skilled to provide you with what you need, just validate what you are being told by anyone in the marine industry(even the stuff I'm saying here). Learn to ask the right questions and/or see for yourself a prototype or previously built boat of the design you're interested in. Look into what other stuff they've done and the final results of those other projects.

Other than that, good luck with your project, if you get stuck, you can always ask questions here.

I am doing some research on him, but out of kindness to him for the deal he is cutting me I am not going to bring up his name.

He is actually well qualified, and worked for a company in Australia for a number of years and is just now moving out to try and start his own company.

I figure some experience is better than none, but thanks for the advice. You pictures have given me a good idea of what I am looking forward to. Keep them coming.

I'll bring up his name (because its me and thats my right). So to answer some questions for Ncik, Gree and others.

Design Experiance:

Multihull:

Off the beach cats through to 100m+ Ferries, via a lot of composite cruising cats.

Monohulls:

Up to 100m (power and sail)

Materials:

Steel, Aluminium, Composite (I personally have designed, tooled and built autoclave quality carbon pre-preg parts).

The drawings I've offered Gree are what I was planing on building myself this winter, however, with a young company I'm not going to have time.

Materials are:

Airex foam (slightly more expensive than most foams but great for first time builders due to its increased flexibility.

cloth: 300gsm double biased e-glass
250gsm e-glass uni
Carbon unis on some internal structure (not unlike ncik's locations although my design has more internal structure).

Hull shape is not for public display yet but has been developed through a typical design spiral including detailed weight estimate, resistance anaylysis and analysis of prefered coeffecients.

I hope this helps put some peoples minds at rest on Gree's behalf.

If anyone wants any more info feel free to contact me at chris at ctmd.com.au (you know what to do) If you visit my web site please excuse it's issues its really a place holder while the development company puts together the proper one.

I hope this helps

Chris.

Thanks Chris, I didn't know how you felt about me saying anything about you or your name so I thought that if you wanted anything said you would say it.

Check you email.

Cool, sounds good. Keep us updated on how it goes.

Next step with my boat is finishing the mould for the centreboards. Although the production boards are looking pretty good, and much easier to obtain.

Why did you removed the old pics ?

I would love to have all the pics from beginning to end in that folder.

Wouter

My advice would be to double check particulars of the design or the design as a whole with others.

People I'm thinking of are Phill Brander etc, using private channels.

In small boat building there is something to be said for having already build and prototypes a few versions of the design. This to avoid some rookie mistakes. One of those rookie mistakes is to use a foam core that is too light, but promises a boat that comes out a minimum weight. And believe me even large professional boat builders have made this mistake.

Also in the way of small beach cats, the right volume distribution can be critical, same with rearbeam clearance of the water etc. So be sure to check the specs against some other succesful designs. Basically double check everything.

Home building a beach cat is a time consuming and expensive project. It is probably only marginally cheaper the actually buying a commericially sold beachcat. You don't want to end up with a dud, especially not if you want it to be a formula boat like the A's, F18's or F16's. Because if it isn't up to spec in relation to others then you can forget selling it on against a reasonable price and recouperate your costs. This is one reason why a designer will be very accomodating when somebody else does the prototyping. I know as I have the same problems with the F12 design and I give the same advice to people willing to help me in that project.

Better save then sorry.

Wouter

Hum, I guess I needed to read-on before replying ! <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Chris, very respectable of you to identify yourself.




I'm much less experienced then you Chris, but my advice here is to use foam that has sufficient resistance against denting. I've seen to many parties try to use a foam that is less "strong" then the basic 80kg/m^3 variety and they all came up wishing they didn't. Structural wise lighter foams are no problem, the problem has always been knees, elbows, buckles/trapezehooks, and protrusions on the trailer. Even with 80kg/m^3 denting can occur, just much less easily then with lighter foams.

Probably you already know this but it is certain a thing to get right straight of the bad as it is impossible to correct afterwards.




If the design is an F16 then allow me to advice you to give special attention to dive resistance and dive recovery. This behaviour is a special and therefor seperate analysis then the hull resistance and prefered coefficients analysis. It is however very important on F16 craft, because the rig can be quite powerful and the large squaretop sails can really press down the bows during gusts. Apart from being a control issue this can also be slow because bow down attitudes create alot of drag. Basically a less low drag hull design may well be faster as it is easier to keep it on its intended waterline. Again I know because I have modified an older design (Taipan) into a F16 myself and have sailed the newer designs like the Stealth and Blade several times. The difference is quite significant. The other aspect is freeboard, with the speeds the F16's travels at you really want ample freeboard, see also a similar trend in the F18's. Beam slap is deadly. So these are hull shape issues.


Pretty much all the other stuff can be modified or corrected at a later time.

Best of luck with the project and it is great to see different people designing their own boats.

I'm looking forward to the first pics and results.

Wouter

The old pics were replaced because they were out of order and I kept doubling up with what I thought were new ones. So I just said stuff it and uploaded a chronological series from scratch.

There are others but most of them are similar to what are already up there.

One thing I'd like to know is how the professional builders heat form the foam easier? My method was tricky and long so I'm sure there's a better way.

If anyone knows that would be great, seeing that I will be heat forming some foam before to long.

How about this way, Notice the infrared lamps ?



Wouter

That might work but I would want to do that in the winter when my garage wouldn't reach 150 degrees in a matter of minutes.

Actually I bet I will have the doors open alot, since I will be out there alot. I need to remember to get that big fan my dad has next time I am home.

Good news about the project, dad just donated some money to the cause for my B-day. Actually when i was young he promised that if I never started smoking he would give me $500 on my 21st b-day. He did it, that is actually the first money he has given me since i moved out. But he said to put it towards the boat. So I will!

you can also score the foam with a router... then fill with microballons/epoxy... then bend... Scrape off the excess microballon mix.. either way works

Hey, just a quick suggestion, if you are going to spend as much as you will on materials you might as well spend 15$ and buy the Farrier study guide (f-boats.com). It outlines the technique pretty well. It also gives you the materials lists from which you can pretty much figure out the layup schedule for the F22 (overbuilt, but you will be getting an idea). It is not complete, you will still have some question afterwards, but it would take me a long time to post everything I learned reading these.

Once, you have seen the technique; then you can choose one of the foams suggested or better yet ALL the foams suggested and ask the manufacturers to fill in the blanks of products to use. Hell, even pose some ambiguous questions to Farrier himself.

You can use just a heat gun (like a high powered hair dryer) to bend the foam into tight radiuses. Most builders prefer this method.

Matt

Yeah, I used a heat gun for this boat but I was hoping there was a better way. Preferably without building a heating jig.

The scoring method might be alright, maybe buying the pre-scored foam with the scrim backing would be the way to go.

It would've been better using thinner foam on the bottom. The curvature of the hull bottom would make-up for the loss of section modulus with the thinner core.