outboard engines for 46' cat

[JimmyDarci]

Originally Posted by Tupaia

You don't mention where the engines are located, rear beam, transom or pods.
Are the props on the current set sufficiently far enough down in the water. A lot of times the lack of power is actually poor grip because of cavitation near the surface.


If you decide to go bigger and heavier. Before committing add some steel/iron weights equivalent the the additional weight of the proposed engines and see how she floats.

Great points, thank you.

Poor grip definitely worse with increased swells associted with high winds. The engines are high thrust but only 20" shafts, in heavy swell off Gloucester and Cape Cod we found the props puling out of the water. Those 25" extra long shafts discussed above may do the trick for this as well.

Props are set on the transom, on retractable "sleds" that tip the engine down or lift the engine up via a series of manual pullies and dynema line. Not hard to lift but definitely a physical boat.

regarding extra weight, thinking 150 lbs extra in total not so much an issue (will just bring less beer) but will defintely place the equivalent of wieght back there and see how she sails.

[mikedefieslife]

Yamaha is the only game in town over 15hp with a high thrust outboard and XL shaft. Honda doesn't have any XL shaft lengths after the 15HP motor. If I'm reading it right the gear reduction is also better on the Yamahas. 2.33:1 vs 2.08:1 so slower speed of the output gear in relation to the input.

The Honda xl shafts are 27" compared to Yamaha's 25". honda's regular long shafts are only 23" so likely too short.

[Cadence]

I had a Honda 15 high thrust with a 28" leg. A little heavy but adding a total of 100#+/- on a boat that size wouldn't seem to be a problem. Nice quiet engine with lots of thrust.

[pelicanme]

Try Boats.net for best price I've found on the 25 high thrust. No affiliation, but have purchased from them.

[purvisgs]

If 20" longshaft is enough- Yamaha, Tohatsu, Honda, and Suzuki are now all making lightweight 20hp's that aren't much more than 97-110lbs w/ electric start.

I'm a diehard Tohatsu fan but of those the 20hp Suzuki gets my vote (on value & proven reliable EFI, and lowest weight w/ power tilt)...... current Tohatsu & Yamaha 20hp are newer models with EFI also worth consideration (in 20" long shaft). Although not high thrust, just optimize the props best you can-----any of these could be a good upgrade for the same weight as your current setup as long as your expectations are realistic.

I know "extra long shaft" could be had for previous generation/s of the Honda 20hp, starting around ~2003, which is also lightweight (~107lbs I believe, ex long carbed) and aftermarket/non factory extension kits are probably available for some models if you are determined enough.

Per previous suggestion, one 9.9 Yamaha high thrust (or replace with 9.8 Tohatsu 25" and save a few lbs) & one 25hph Yamaha...does seem to make a lot of sense- as long as you're not selling the boat & you can live with the uneven "look" !

Sounds like a nice boat, would love to see some photos

[Cadence]

Originally Posted by Cadence

I had a Honda 15 high thrust with a 28" leg. A little heavy but adding a total of 100#+/- on a boat that size wouldn't seem to be a problem. Nice quiet engine with lots of thrust.

PS, a real generator, comes with controls shift and throttle. power trim and tilt. No tiller handle so a steering cable can be fitted.

[pedro b]

Hi All
On a 37 ft Crowther cat I have just replaced a 2000 model Yamaha 25HP high thrust with the latest injected model 25HP high thrust. Very happy with the added features of the new model, better fuel economy, flushable, light weight, rope start already fitted etc etc. However, for low down thrust, especially in reverse, I was disapointed. On checking the prop diameter the latest model has approximately 2 inches less diameter and no room to fit a larger diameter prop. The current prop is 10 5/8 x 6 3/4-F which I am told by Yamaha is the finest pitch available. Perhaps a 4 blade Yamaha prop may become available for this motor???
Set up is single, stearable Yamaha high thrust on a central pod. 4.5 tonne boat gets 8 knots in flat calm water but cruise at 6.9 knots at approximately 60% power. Sorry no rev counter. The 2000 year model with 12 inch prop was definitely superior in tight manouvering and also strong head winds.