Engine & prop

[tomdmx]

My yacht (a 31 foot steel sloop cutter rigged) has an old but what appears a reliable lister 18hp twin engine. She doesn't however appear to have more than a 4 knot top speed so I'm a bit concerned in fighting a currant etc...

She also has a twin bladed prop...so would a way to more power to change to a 3 blade prop

Also does anyone know the lister engines and their sustainability..i'm going across the big drink in december so wonder on parts availability etc as i'm completely unfamiliar with this engine type

 

[MrCramp]

I guess your boat weighs plenty so it would not surprise me that you don't have enough power to go faster.

 

[Neil_Y]

Small engine and a heavy boat, is the engine reaching max revs? if it is then more pitch may be the answer but you should talk to a prop expert, like hamble propellers.

For the Atlantic you wont need an engine, go in Jan and there will be wind all the way.

 

[Tranona]

Old style Lister engines will go for ever. However, they are crude by today's standards and most have now been replaced by more refined and powerful types. You will not find much in the way of service support, partly because so little goes wrong and partly because there are now so few about.

As to speed, that is not enough power to achieve even hull speed, but you might be able to improve it by a 3 bladed prop. You need to do the calculations using a programme such a Propcalc www.castlemarine.co.uk. However a 3 blade will create extra drag when sailing and guess your boat probably needs all the help it can get to achieve reasonable speed under sail.

 

[yoda]

Castle Marine have an easy to download and use programme for calculating optimum prop size. Worth a quick check to see if you are in the right ball park with your current prop. If you don't have a tacho then worth buying a cheap hand held one from flea bay so you can check what revs you are achieving.

Yoda

 

[tomdmx]

thanks for the information, unfortunately the program doesnt work on my laptop (i've a 64 bit and this is a 32 bit app)..will try from work pc but i think they are 64 bit also...which is a bit of a shame...