Ship’s boats with engines

[George1943]

Hello

I am building a 1:48 scale model of a steam yacht (MM1036 plan) and I have a bit of research I cannot complete. She has a 24’ boat with a motor but only a plan view. I cannot seem to find a view anywhere that shows the elevation view showing how the prop emerges! I think there are really only 2 possibilities.

1. The prop shaft emerges at the transom so the rudder has a cutout to avoid the prop or…..

2.  The prop shaft emerges in the keel which has the prop cut out so the rudder runs straight from gudgeon to pintle 

 

I should also say that the boat has a transom, not double ended.

 

Any assistance will be really appreciated!

[Jim Lad]

George, the usual arrangement would be for the propeller shaft to emerge through the skeg at the stern. If you google something like 'small motor launch plans' you'll find a lot of examples.

 

John

[George1943]

Thank you Jim. Found a whole lot of posts as you said - through the Skegness. It just proves how important it is to Google the right form of words! 
 

by the way, I spent months commuting between Sydney, Melbourne and NZ around 2009 really loved Sydney - hated leaving which was the first and only time I felt like that about any city I ever visited. A fast food mobi outside the Opera house gave me an enduring taste for ‘Pie Floaters’!! REAL man-food!! All the Best! And thanks again

[allanyed]

Welcome to MSW George. Is this boat for the steam yacht Greta, 1895 or some other vessel and year?  In what country was she built?  Finding an appropriate motor driven ship's boat might be a bit easier with a little more information.  There are a lot of designs I found on the internet including the one below of a 30 foot boat of 1911 but it may be totally inappropriate in design.  If you have not already  contacted the folks at the the Royal National Lifeboat Institution, they may have some useful information in their archives.   https://rnli.org/about-us/our-history/archive-and-library

Allan

 

Edited October 2, 2023 by allanyed

[George1943]

Hi Alan

yes it is the Greta and the boat in question is a 24’ Cutter with a square transom (ie. Not double ended) the boat is completely open with no covered sections.  It sure if the boat dates back to the original launch date or was added or re-fitted later. The plan view suggests a diesel/petrol engine rather than steam so may have been added later 1914/18 sort of era. I know my Grandfather had a car in the 1890s (his RAC membership number is 9 in Co Kerry!!) so engines were pretty crude

[Roger Pellett]

Can’t help much with the propeller arrangement except to say it is dependent on hull form.  If your plan view shows a square stern then the simplest and most likely arrangement would be the solution as posted by Jim Lad.

 

The engine itself:  I believe that a 24ft ships boat c1914 or earlier would have been powered by a petrol (gasoline) engine.  Prewar WW I Diesel engines were big, heavy, and complicated.  The major problem under development in 1914 being the fuel system.  The Diesel cycle, unlike the auto cycle requires injection of fuel to the cylinder at or near peak compression pressure.  To do this, early diesels required a separate compressed air system.

 

There were also semi- diesels.  These used glow plugs  in the cylinder head heated with a torch to provide ignition heat while starting the engine. Once the engine got going cylinder heat kept the glow plug hot.  Here in the US, these were popular with commercial fishermen.

 

 

The spark ignited petrol fueled auto cycle avoided these complications although the volatile fuel was and still can be dangerous aboard a small boat.  There were many different patented varieties of these engines.  Pick a likely one for which you can find drawings.

 

Roger