Part of the pleasure and satisfaction of owning your own boat rather than part ownership or chartering is tinkering with things to make the boat as you want it to be, rather than changing your behaviour to accommodate someone else’s ideas of how it should be !
Although in the past its been possible to make and modify things in wood and metal or GRP, there were always many small bits and pieces that could only be made in a factory context, such as small fittings and parts. The arrival of 3D printing as an accessible hobby activity has opened up a whole new range of possibilities for making bits and pieces for boats (as well as most other aspects of life!) and as I spent a lot of my professional life as a design engineer, I found it perfect for making myriad bits and pieces to make life simpler on a boat.
3D printers themselves are now affordable – a simple one costs less than £150 and the best hobby machines up to about £1500 , and the materials (filaments) are not expensive. You can use the printers in two ways – either designing you own parts, which involves mastering one or other of the (usually free) Computer Aided Design programmes (CAD) such as Fusion360 or Onshape or several others (check the web for ‘free CAD software’ ) or the simple child friendly Tinkercad, or downloading designs that you can configure for your own printer and choice of filaments. ( I use a CAD program -Solidworks – that I pay around £100 p.a. for as I used it professionally for many years and am familiar with it.)
3D printing is well within the reach of anyone of a practical turn of mind who is reasonably confident using a P.C. for normal activities and who can cope with modern navigational systems in a boat, and, particularly important, is happy to use the web as a source of information when faced with a technical problem! Because so much information is available on You Tube videos and on web pages I’m not going to try to replicate it here.
I am putting some of my boat oriented designs on this website in the form of files in .STL format. This format, which stands for STereoLithography , is just a 3D representation of the outside shape of the object reduced to lists of the 3D coordinates of the corners of surface triangles covering the object – if that makes any sense to you! In making the .STL files from the internal representation of the object you have created within the CAD program the computer (and ultimately the user) can choose the resolution with which the conversion happens, and hence the surface smoothness and also the file size of the .STL file. For my own use I use a different representation, called STEP, that gives true curved surfaces but is less widely used for publishing files, so I’ll post here in .STL format.
Given the .STL files as provided here or on a number of sites where 3d printing designs are available, either free or for a small payment, you’ll need to prepare them using a ‘Slicer’ program like Cura , Prusa Slicer or the Bambu Slicer that knows how your 3D printer is configured and can be set for the filament that you will be using for the print and the particular parameters that you wan to set relating to the strength of the print, such as the layer height, wall thickness and how solid you want the infill to be (most things are not printed as solid bodies but have partly hollow insides with variable amounts of thin wall strengtheners – usually quoted as % infill, 10% being a reasonable minimum for objects that don’t require much strength to 100% for solid objects where the maximum strength is require ( 100% is very seldom used – it used a lot of filament and takes a very long time to print – 15 to 50% is a usual range, good design and correct orientation on the bed, coupled with adequate number of layers in the walls is usually enough to give the required strength. Once your slicer program has finished processing the .STL file it will output a file that your 3D printer can understand written in GCODE, which is simple a text list of instructions to the printer setting the printing temperatures and moving the print head and bed to the required positions and controlling the extrusion of filament, and any special instructions you printer needs to function.
For use on boats it is particularly important to choose the right filament for the job in hand, so here is my take on the generally available filaments that you might want to use;-
PLA or polylactic acid is derived from corn starch with additives and is available in many colours and variations – tough, matte, plus etc plus any number of additives like wood, metal or carbon or glass reinforcement. IT is the most common and easiest to use filament, and is as strong as most other filaments, but suffers from a couple of weaknesses from a boat perspective – Firstly it has a low softening temperature, so if left in bright sun on a hot day it will soften and things will warps, secondly it is quite brittle compared to some other filaments and can break under stress because it doesn’t flex to redistribute the stress more evenly. It isn’t supposed to be suitable for use outdoors, although I have had things outside for years and they still appear to be pretty strong. It is by far the easiest filament to print with, and beginners should start with it!
ABS, ASA and Easy versions. These are supposedly better outdoors and do make strong prints and have a somewhat higher softening temperature so I use them in preference to PLA for outside fittings. My prints in ABS or ASA do have a worse layer adhesion than for PLA which always prints very solidly, but otherwise its fine – it has the advantage that its soluble in acetone, so a slurry of ABS or ASA in acetone can be used to glue parts together, allowing things to be printed in parts and bonded later.
Nylon, also labelled PA, is very useful when the softening temperatures of PLA or ABS etc are not enough – for example fittings for heater ducts for the common types of diesel heaters used on boats. I have made use of it extensively for that purpose. It does require a high temperature ‘hot end’ on your printer, and so may be beyond the capabilities of some cheaper printers. There are a couple of disadvantages to using it – firstly the filament is very susceptible to absorbing moisture from the atmosphere and so needs to be stored in a low humidity environment ( <35% R.H.) or dried out before use. It won’t print properly if it has absorbed moisture as the water boils out as it heats in the hot end. The other snag is that support structures – the bits that the slicer program puts in the support overhangs – attach themselves too well to the bits they are supporting and are difficult or impossible to remove and clean up. The solution to the latter problem is to design parts with minimal overhangs – if necessary by making them in bits that can be assembled after printing – although bonding nylon parts is difficult. I’ve resorted to designing heater duct junctions with rectangular outsides and cylindrical internal airways – effectively letting the permanent infill take the place of the support structure.
Carbon or Glass filled filaments – there may be situations where you need the extra strength of one of these filaments, and I have used carbon filled nylon for ducts, but you need a special hardened steel hot end on your printer of the extra abrasive nature of the infil will damage the nozzle
Its also worth mentioning that there are many services available on the web that will take designs in .STL or other formats and print them in a wide range of materials including sintered aluminium and stainless steel. Some of these services also offer to scan parts and print copies – so that hard or impossible to get broken parts can be replicated without having to program them in as CAD files – a very time consuming job for complex parts.
I intend to put a number of .STL files for objects on this site that you are free to download – see the ‘3D Downloads’ page.
My 3D printing is now exclusively on a Bambu X1 Carbon with a Multifilament Unit that I only use to save having to reload different filaments. I’m using Solidworks deal for hobbyists and startups that costs around £100 p.a. and the Bambu slicer program which is very convenient as it communicates wirelessly with the printer and you only have to go to the printer to take out the finished parts and clean the bed, or to replace filament that has run out – usually after very many models have been printed. The whole setup is very quick and troublefree, and I can do a new design very quickly, print a trial, and modify the design if necessary in not much more time than the printing takes. In the past I’ve used a cheap Artillery printer that was very good until the LCD display packed up, and a Prusa printer that I thought was overpriced for what it was, and which developed some unresolved printing faults. Both now sit in my workshop unused!