Outboards on small power catamaran

[CatrigCat]

I'm thinking of building a small 23' power cat with 2x15 hp outboards.

If there is a sudden storm or squall, am I correct to assume that soon both engines will be flooded leaving the boat at the mercy of the waves?

Leon

 

[Mr Efficiency]

Is this a boat for which plans already exist ? There is no reason why engines will be submerged, unless you select the wrong shaft length for the job.

 

[CatrigCat]

I' ve looked at a few designs but haven't bought any plans.

Such small cats have narrow hulls that are either sealed or just for storage. Without any flare and reserve boyancy, won't a wave almost cover them?
That's not a problem if the outboard is not running but if it is, water will certainly be sucked in.
The hulls just look so narrow.

 

[Richard Woods]

It hasn't been a problem with my Skoota 20 or 28 and I have done thousands of miles in those two boats. I haven't heard of people having problems on any other powercat either

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

[bergwerk]

The OP would do well to search for a Hirondelle 23'. They come up occasionally in the low teens and he can, if he wishes, remove the rigging and have his powerboat.

He'd be light-years ahead in cost and frustration.

I sailed one in an earlier life in the Med and was quite impressed with it. In fact that same boat was later rigged with a pair of portable OBs and her owner reported his complete satisfaction with his "motorsailer".

http://sailboatdata.com/viewrecord.asp?class_id=5021

 

[CatrigCat]

OK then.

I have no experience with catamarans and the hulls look so narrow compared with the overall beam.

I like your Skoota 24.
Being trailerable is very very convenient.

 

[Mr Efficiency]

I' ve looked at a few designs but haven't bought any plans.

Such small cats have narrow hulls that are either sealed or just for storage. Without any flare and reserve boyancy, won't a wave almost cover them?
That's not a problem if the outboard is not running but if it is, water will certainly be sucked in.
The hulls just look so narrow.

Actually, any such problem is more likely to manifest when engines are stopped, as there is the possibility of water entering the innards via the exhaust. But in reality, there is no problem if you select an engine shaft length that puts the powerhead well above the static waterline. In the old days (40+ years ago), it was dicey fitting the then 20" shaft engines to slim-hulled trailer cats, engines were drowned sometimes, but the advent of 25" legs largely solved it.

 

[Steve W]

25" legs exist on very few motors, mostly 8 and 9.9 high thrust models but you probably don't want high thrust. Most long shafts are still only 20".

 

[bergwerk]

Not exactly.

Most brands' 90 hp and above are available in 25" and several of the V6/V8 come even in 30".
Back to the little ones, there is plenty of 5" extension legs to be had for all brands. This is just one of the many sources, starting with the 9.9 hp motors:

http://www.marineparts.com/partspages/accessories/acc8.htm

 

[Steve W]

I am aware of the 25" legs on large motors but I didn't mention them because that's not what this thread is about. I'm not aware of any off the shelf motors in the smaller sizes above the aforementioned 8s and 9.9s of which most mfgs sell. But yes you can add extension kits, in fact I just talked to the folk at Bay mfg yesterday getting prices for 25hp Yamaha and Tohatsu which were around $500.

 

[CatrigCat]

Honda 15 hp is available with X shaft (25") and also e-tec 15 hp is available in X with direct injection and higher than 15hp (h.o.) but a lot heavier than the honda.