Outboard engine length for lake boat.

onelastcast

Hello boards,

I have recently acquired a lake boat and i am going to buy a new engine at the weekend. I have rented boats for years so never really payed attention to weather the engine on them was a long or short shaft.

I am slightly confused about the height of the transom so was looking for some advice on weather it would be a long or short shaft engine that i need. I am looking to get a 15hp 4 stroke.

I have attached an picture i took. It looks to be around the 25 inch mark.
Could someone please adivse?

onelastcast

link for image is in the title, apologies this is the only way i could do it as i am a new user.

viper123

Looks like a standard transom so it just comes down to the lake you are on and the likelyhood of hitting rocks etc. I use short shaft on 6hp and it is fine for me on any of the western lakes.

onelastcast

viper123 wrote: »

Looks like a standard transom so it just comes down to the lake you are on and the likelyhood of hitting rocks etc. I use short shaft on 6hp and it is fine for me on any of the western lakes.

thanks for the quick response. I mostly fish lough derravaragh and lough derg.
would a longer shaft have any performance issues on the boat?

coolwings

onelastcast wrote: »

thanks for the quick response. I mostly fish lough derravaragh and lough derg.
would a longer shaft have any performance issues on the boat?

The boat will work just fine with a long shaft, but you'll be going slower, and lifting and tilting the engine earlier every time you approach the shoreline or enter rocky shallows.

demanufactured

Short shaft on a lake boat.

delboythedub

Measure your Transom first before you buy an engine if engine shaft is too short it will break your heart. What make of boat ie anglers fancy,guilty or wat

demanufactured

delboythedub wrote: »

Measure your Transom first before you buy an engine if engine shaft is too short it will break your heart. What make of boat ie anglers fancy,guilty or wat

It won't matter, you can't measure the transom on a lake boat, because they are a displacement hull.

It's only relevant if you have a planing hull.

Short shaft in a lake boat.

delboythedub

demanufactured wrote: »

It won't matter, you can't measure the transom on a lake boat, because they are a displacement hull.

It's only relevant if you have a planing hull.

Short shaft in a lake boat.

" Can't measure the transom" Top of stern to bottom of keel called Transom height ?? Lake boats can be long shaft or short shaft and too short a shaft will will make the engine prop spin on the surface of the water called CAVITATE . One hundred percent recommend you phone a outboard dealer and ask him. Think before you buy.

demanufactured

delboythedub wrote: »

" Can't measure the transom" Top of stern to bottom of keel called Transom height ?? Lake boats can be long shaft or short shaft and too short a shaft will will make the engine prop spin on the surface of the water called CAVITATE . One hundred percent recommend you phone a outboard dealer and ask him. Think before you buy.

If you measure that way on a lake boat you'd probabaly end up using an XL shaft and using lots of fuel.

onelastcast

thanks everyone for getting back to me on this

butrasgali

Would a 3.5hp outboard be strong enough for a 10 foot rib..I don't have any experience in this and just wondering is it to small..cheers