Sea Sled madness. It’s in my brain.

Certainly I'm highly motivated to try something. She currently has horrible mileage. 1⅓ miles per gallon/180 liters per 100km isn't useful. If I'm going through that much fuel, I should at least go fast.

 

I got out the hole saw and the shop vac. Pulled 730kg/1600# of rain water out of various locations.

Since Serenity is supposed to weigh 2200kg/4800# in normal trim, that's ⅓ over. Enough to negatively effect Vmax.

Step one in the campaign to get a bit more speed.

 

357mm*432mm/14⅞*17" prop. I've ordered a 394*457mm/15.5*18" prop with cup to replace it.

Outboard props always make me roll my eyes. I was banging my head against disk area/propulsive efficiency relationships back when I was doing aircraft design studies. So far back I wasn't even bald with a potbelly yet. And that's waaaaay back. Outboard props are not efficient.

 

.....compared to what? And what efficiency do you think your'e getting then?

 

Eliminate the issue, fill in the source of the aeration "hole":



And taper up fwd.

 

What manufacturer?
How many blades?
What's the cup measurement?
Material?
Price?
Pictures?
Specs?
Anything?

 

I'm just comparing them to an inboard. Scrolling through pages after page of props in a dealer's catalog and tables of props are labelled "for engines 115hp and up." And the like. The prop for my 250 HO has 30% more disk area than the prop for my 70hp Johnson.

I spent many hours clutching my head trying to design my way past the fact that thrust is proportional to momentum transfer: mv, but power required is proportional to KE: ½mv². Outboards, at least in my power range, have tiny little props. It's like designing two vessels, one with 5000 shaft horsepower, and the other with 15000 shaft horsepower and using the same prop.

 

Quicksilver. I found it in the wholesale catalog at Landnsea.com, not a lot of information there. Three blades, aluminum, meant for heavy slow boats with high power. Apparently that's me.

 

Did you stop the source of the ingress? Asking as a friend..

 

I've found it, not sealed yet.

 

Got a plan or need advice from the peanut gallery or just time?

 

Just time

 

Maybe it would be even less effort to just drill a few limber holes and install a cheap bilge pump, maybe wire it to an inexpensive car battery to just keep it independent. (Not trying to be insulting or mean, I know it's basic.) It might be a lot less work than trying to get your vacuum into all those nooks and crannies... I know I loathed sucking even a few gallons out of the bilge in my forward cabin which had no pump. It liked to collect 40 gallons a day of condensation water from my forward a/c unit with a worthless drain hose.

 

The limber hole boat has sailed. Not possible without major destruction. My approach now is to prevent water ingress in the first place.

 

And for folks who like pictures of water...