What Others have been Saying and Asking

This is the “feedback” part of the site, snippets from emails and other forms of communication.


A question from Nigel

I am experimenting using plastic weld liquid which seems much better than epoxy based glues which don’t bond to 3D very well in my experience.


I use fairly traditional adhesive processes for the PLA and PetG materials I am currently using. I have seen successful welding methods but haven’t experimented yet and probably won’t because my current methods seems strong and rigid.

I prepare the surface by thoroughly washing with methylated spirits (denatured alcohol), then fine sand the surface with fine abrasive. The methylated spirits takes the very slight residual “oiliness” from the surface that comes with thermoplastics. Drastically increases the stickiness in my experience. 

Then use either good quality superglue (eg Loctite professional) for small tacking jobs or good quality epoxy for the heavier things. Sometimes mix filler in with the epoxy for filling jobs. I try not to make the epoxy too think because it can warp the hull as it cures.

The other hint worth adding here is that leave the epoxy for an hour or so before applying. When it is like thick honey apply it to the surfaces glue. The big advantage is it appears to stick better and also it doesn’t run everywhere. Thickening with talcum powder or microballoons accelerates the “tackiness”.

Good luck with it all. 


A question from Nuno

  1. What have you found to be better for gluing/bounding the hull parts?
  2. Do you make any post processing for the hull? Or sanding is enough? Asking this thinking on water gliding/friction. (hope you got the point, my English is a bit rough)


Hi Nuno,

PetG is a good allround hull material but can get wobbly in flat spots if it is not printed thick enough. If you have trouble with it try PLA if you are doing smaller yachts, it is a bit stiffer and easier to print. 

I personally use the Pet G for the larger hulls and PLA for the smaller and now PLA for all the parts to be added to the hull.

Gluing is easy:

  1. Wash the area to be glued with methylated spirits then sand both surfaces slightly to rough them up.
  2. PLA and PetG both will glue well with a good quality epoxy or superglue.

Experiment with small pieces first.

I have worked hard to get good surfaces in the printing. So happily do nothing with surfaces … just go sailing. The slight printed roughness seems to have no affect on performance from our extensive (and by others) testing. Make sure your drive mechanisms are all firm but not tight and that you don’t try to print the hull too fast… use vase (spiral) mode with a thicker nozzle if you have one. I run the hull printing and other things at about 60-70% of “normal” recommended speed.

Good luck, I will warn you it is all often frustrating but also VERY addictive.

Hope this helps.


The latest on Philipp’s work in Japan.

“After the success of my 3D printed RG65 (as published on thingiverse), I am now working on a new design IOM, in ABS this time. The design concept is similar, with the hull in four segments maxing out both on height and width of the printing volume of my little Kossel printer. 

I also printed Bill Hagerup’s Footy from thingiverse, and it sails fantastic. Tons of fun, big thanks to Bill for publishing and for the good instructions on your page.”



Hi Selwyn,
Kayne Jacobson
Auckland, New Zealand.
I am a draftsman that has been 3d printing for a few years now and sailing for much longer and until seeing your research and what you have developed I had never thought of using 3d printing for full RC sailboats. From what you have done it has inspired a friend and I to embark on our own journey with 3d printing and RC yachting and I would like to share where we are up to and ask a few questions.
For years now a friend and I have been match racing our two Tamiya Yamaha round the world RC yachts and have always wanted more. We both a have a background in competitive single handed sailing and two handed skiff sailing so were looking for something that was more difficult and a handful to sail rather than something to fine tune like a IOM.
What we have come up with so far is based off a design by Claudio D, I picked up free online. It is a concept of a monohull off the hype for the 33rd americas cup. He called it the AC33. We have scaled his design from a 10R sizing to 1.6m with a displacement of 9000g. We have also added the ambition of including an asymmetrical spinnaker and conventional genoa for the challenge of it. We are also designing our own hi torque servos and Arduino based system to control automated hoisting and tacking/gybing procedures.
Currently we have taken a slightly different construction approach to our design in the way we print everything internally in one hit with a lot more strengthening in the form of ribs and bulkheads, the ribs were a bit of a requirement to hold the large volume of the design without warping. The construction method is a lot like what 3d lab prints are doing with their planes. We are still in very early prototype stages with our first hull being almost complete, its overall weight will come to about 1200g, this includes all servo boxes/mounts, pulley mounts and keel box/rudder shaft. With this first prototype we are testing joining methods ,weight distribution and strength, it may also be used to start testing out rig fittings and appendages. 
All going well we will have something sailing in the next three months.
As for a few questions if extra strength is needed how were you thinning and applying your epoxy coat on your early models? Did you spray it on or apply it with a brush.
Also when you have made bulbs by 3d printing a shell what are you suing to weight them? My best thought is to fill it with lead shot for shotgun shells (75NZD/KG) and once a weight/shape is decided on fill the remaining space with epoxy to make the whole thing solid.
I hope I have not written a to longer email and taken to much of your time away from developing your own boats. If you want to post any of this on your page please remove/rewrite what you like. I have also included some photos of where we are currently at.
I look forward your comment.
Best Regards,
And now nearly complete.

Dear Kayne,

I am amazed at what you have achieved so far. Great work. I love the intricate CAD work you have done, there is so much more for us all to learn in this journey.
What is the filament material you are using? Or is it multiple types?
I’m nearly finished a 10R at the moment and all the research with the Footy, RG65 and IOM has paid off. A big beast like yours has some interesting stress and strength challenges whilst trying to stay nice and light…. as i’ve found out with the 10R. Our next project will be a 14kg International A Class, now that will be something and is of the size you guys are working on now. So keep me informed of you progress if you don’t mind.
Now to the bulbsl, I pre-determine the volume (based on the density) of the bulb needed, print the shell and then alternate fine lead shot with epoxy. That is, add some lead from one end, fill the spaces with epoxy then more lead and epoxy etc. It is important to do the lead first to get a higher density. Then cap the end. All my RGs use that system, but the IOMs and 10R have standard lead keels.
Epoxy washing can be sprayed or brushed on the outside if you wish … allow to drain well. But if you work on achieving a fine finish to your prints why would you coat them? I only sanded and coated  the first few because I was not good at the finish then. Then I went through a stage of epoxy washing the inside to seal it better, but don’t do any of that now. Just raw hull, fit the parts and go sailing.
If you get a reasonable externally smooth 3d surface it has no effect on the hull hydrodynamics. Just ask sharks and also do some reading on Reynold numbers.
The epoxy washes I used were a good quality epoxy with 10-20% methylated spirits added. Thins it right out and flashes off the large surface area before the epoxy starts setting. Don’t use this method for thick epoxy uses like bogging in parts.



Hello Selwyn,

First of all a huge THANK YOU for the inspiration your site provides. Especially the spiral vase method was the key for me to achieve usable hulls. I printed Andreas Hoffmann’s manta2017 RG65 design and was very surprised to find myself on 3rd place of 15 in the Southern German RG65 ranking event on August 6th.

My findings are the same as yours – the inherent roughness of the hull printed in 0.2 mm layers does not slow the boat down at all. I use the hulls as they come off the printer. Even the designer Andy Hoffmann himself (he came second) was very impressed after sailing my boat for a couple minutes.

I am documenting my story in the German RG65 forum: http://www.forum.rg-65.de/viewtopic.php?f=24&t=2071

Philipp from Japan


A Few Questions From Antoine

Dear Selwyn

You  made great with 3D  IOM boats !!!!! Its like a revolution… Tx to you!

I’m a French IOM mesurer and  my question is as such :

-Does the material of synthetic 3D printers is specified by the IOM rules ? (D2.1)

– how do you join the hull’s sections ?

-The quality of your hull’s surface does not look so good (asperities and bumps with 3D) how do you justify it’s efficiency?

-what’s the weight of the hull  with all reinforcement before electronics ?

Antoine FRA

Dear Antoine,

Yes, we have been surprised and proud of what has been learnt and how this 3d printing technology can revolutionise our beautiful sport. 
Thanks for your encouragement.
To answer your questions:
1. D2.1 allows thermoplastics for the hull and support structures and that is the basis of the 3d printing. We generally use the most common thermoplastic called PLA.
2. On the site the published articles at the bottom of the home page describes all this and there is more in the next article being published right now with Model Yachting (USA)…. and will appear on the site in due course. In summary, there are many ways to do this from bulkheads to special joiners and short support sleeves. Epoxy and most superglues grip the PLA tightly if sanded first.
3. In the early stages when we were learning the process, the surfaces were a bit rough. We would then sand them and gloss them as part of the process to get a prototype into the water. Then as we tested more and more, the surfaces became very smooth. At one point I decided to sail the prototype with the surface raw and this surprisingly went easily as well as the glossed surface… so we went through more testing with that and decided that the surfaces we produce now are best left alone because they seem to be superior to paint in terms of scuffing, cracking and chipping etc. Also, keeps the weight and preparation time down. Most good quality amateur machines will give an excellent finish also if done properly. Attached is the latest hulls I’ve produced here with silky smooth hulls… a USOM and a Nano (a new 3d printed dedicated class created by the IRSA for those interested in 3d printing)
US One Meter and a Nano
4. The IOM hull when prepared normally with all the racing gear and rigs attached can carry up to 250g of corrector lead in the hull to bring it up to 4000g. This is with a nice and resilient hull being printed. Lighter hulls can require more lead but what is the point, we would rather produce hulls that can survive the rough and tumble of racing… especially B and C rig conditions.
Hope this all helps Antione.
All the best.



The Word Is Getting Around
I scratch built a plywood footy and Bill’s Half Pint II and designed a couple more footys in 3DBoatDesign about six years ago.  But it was so much effort to build round bottom boats that I never built these designs.  I had been looking at 3D printing for several years too. Then I found your site on 3Dprinting boats. This was the incentive I needed to buy a printer.  I got a large volume 300x300x400 mm (Creality CR-10) printer for only $400.  I can hardly believe how accurate and smooth and light the prints are.  Now I can make a boat design in Delftship Free, slice it on end in spiral “vase” mode, and in two hours is printed a perfect full size footy hull.  What fantastic instant gratification.  Now I can hold the full size model hull and decide if a design looks right and if desired change it and print another.  It is hard to imagine building a perfect hull in just two hours. I haven’t figured out the details on keel, bulb, equipment, and mast support and attachments yet and I would appreciate any more details you are willing to provide. Thank you so much for sharing your technology and providing inspiration.  These techniques certainly ought to help popularize RC sailing since building is so much easier.  Now if I could only find other Footys to sail against.


Just Like The Internet

Wow! I’ve seen Selwyn’s  3D boats sailing/racing and I’ve gotta say this is like when the internet first hit 27 years ago:

  1. Initially everyone was sceptical
  2. Everyone “bagged it”
  3. It then proved itself to be a “game changer
  4. Everyone wanted it
  5. It becomes mainstream and everyone accepts it as “the normal” from where the next breakthrough comes from




From the web site: “3D printed boats”

(Snippets from the RCsailing.net forum)

For the past year or so, I’ve been collaborating with my Australian friend, Selwyn Holland, in what we think is a project that represents the future of Open Class development.

That may sound like hyperbole, but we have been able to combine my design work and Selwyn’s engineering to produce 3D-printed boats. I realize that a number of you have printed fittings successfully, and some have experimented with hulls, but Selwyn’s extensive experimentation and testing have made 3D printing a viable alternative to any other construction method…and a better one than most.

Here is a picture of one of our RG65 prototypes on the water:

Click image for larger version Name: IMG_2973.jpg Views: 22 Size: 942.4 KB ID: 16135

If that intrigues you, check out his new website here: https://3dprintedradioyachts.com

Still having fun with toy boats……….Bill

(Bill is a long term designer and advocate of all things RC Yachts from the US)

Hi Bill,
Yes I’m intrigued and skeptic at the same time, but always curious !
Most intriguing me are the weight, strength and costs once applied to a larger boat like a class M.
Ageing effects ?
I shall read the content of the link…


I understand the skepticism…but this really works. The largest boat we have on the water is an IOM…but Selwyn will be doing a 10R when time permits. A couple of test hulls were printed. Eventually, I think we will do all of the International classes.

The weight and strength are no problem…comparable to carbon hulls. We waited to go public with this until we (mostly Selwyn) worked out the kinks and until we had boats that proved they could win races. Once the initial investment is made in the technology, printing a hull is dirt cheap. Of course, this is too new to know about the effects of aging.

Since you already have the CAD skills, you just need to find a friend (like I did) who has a good printer. Even working across the globe, Selwyn can ask me for a change, I can do it and send it via email, and he can have it printing the next day. The slowest part of our turnaround time is when he has to send me stuff through snail mail.
I just Googled about UV resistance…turns out PLA is highly resistant to UV radiation.



Printing my own RG


      This is excellent. I’m in the process of hopefully printing out an RG of my own. Reading through your site, I’ve gained some helpful insights and look further to your further posts. There are a couple things I’d like to talk to you about. I won’t be there on Saturday as I’ll be up at Lake Macquarie for IOM#2. But looking to catch up with you sometime.


(Secretary of the Wollongong Model Yacht Club, Australia)


Nice site

Hi Selwyn,

Nice site & great that you’ve received so many visits.

Lookin’ good there, son. 🙂

Regards, Laurie..

(Long term RC sailor, Australia)


No Strings Attached

Hi Selwyn

Just had a look at the website after your enthusiasm  for the future of 3D printing in RC yachting this afternoon.

You should be proud of your achievements and ground breaking methodology which you are quite happy to share with no strings attached!

I tip my hat to you well done and keep up the great work!


(long term big boat sailor and now RC. 25 years as Club Captain at the Port Kembla Sailing Club, NSW, AUS)


Not A Single Drop Of Water…

Well Selwyn, I have more good news!

 I was admiring one of the hulls yesterday, thinking I actually prefer the finish from the printer, without the epoxy coat.  And with your awesome printing skills, it looked really tight.  So I put a pound of lead in it, taped up the ends, and floated it in the laundry tub…oops, I mean the test tank.  Left it there for 12 hours.  Opened it up this morning and there is not a single drop of water in it…not one drop!

 Awesome job, my friend………..thanks.