Hi All,
Thought you all may be interested in my designs for a full size 30ft steam launch.
It is still in the design stage, had more pressing matters to deal with, and probably won't get started for the next 4-5 years, however a model will be built to test the design.
It started out as having the design brief from myself of;
1- Must be fast, light and efficient hull
2- Easy to steam one handed
3- Seating for 9/10 passengers
4- Must have a cabin (swmbo!), prefer lighter open launches myself, but hey they have advantages, and i'm thinking of 3mm teak veneer over aluminium frame with foam sandwich giving traditional finish but negligible weight disadvantage
5- High speed quiet single acting engine with useable power range
6- As large a pitch as pos' with a fairly small diameter giving fast pickup- high revs for full power and shallower draft
Since doing the hand drawings last year I’ve messed around with the hull design on DelftShip and managed to get it down to a negligible resistance (almost nothing, didn’t know how I had the patience to tinker that much!) using a more conical hull under the waterline with almost a constant entry angle for the entire length of the hull for’rd, also kept displacement to 1.5tons which gives a decent power to weight and power to length ratio of 1.2 would give an engine of 35hp.
I’ve included my hand drawings and also the Delftship renderings- interesting comparison from my original design by hand with no calculations just aesthetically designed by eye and then Delftship’ed to suit the aesthetics and fill the rest of my brief.
Also I’ve included my engine design, clutching at straws really, it is loosely based on the Willan engine designs, normally three cylinder, high speed single acting engines with a similar throttle to the cheddar integral throttle/reversing block. However this design has never really been proved- it relies on having the best seal between the steam side and the crank-case possible. However, even if it was changed to double acting I would like to keep the IC engine inspired no piston rod design. Its’s 4 x 4”x4”.
You can see the first design was a 1234 ‘firing’ rate and had a two bearing crankshaft- after advice from experienced steam engineers this was changed to ‘1324’ and 3 bearing crankshaft.
I was also going to use the Yorkshire Wagon type boiler- fast steaming, decent water reserves and a proven design. However it is also very heavy and would have bogged down the launch in exactly the wrong place so I’ve ditched it for a lightweight steel/copper Yarrow boiler design.
So, comments please, and I hope you enjoy looking at my designs.
Greg
Author
Topic: Fast Conical Launch Design (Read 6149 times)