prop sizing for 36' tri-cabin

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jhdean
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prop sizing for 36' tri-cabin

Post by jhdean »

Due to a recent grounding I am replacing both my props. The old props are 18 x 18 3-blade however the yard where my boat is has a pair of 18 x 18 4-blade props in stock, any thoughts on how these will perform on my boat with 350ci Crusader Marine engines? The yard guy thinks I should have the 4-blade props re-pitched to 17, any thoughts on that? Thanks.
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prowlersfish
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Re: prop sizing for 36' tri-cabin

Post by prowlersfish »

you did not say what year the boat is . But going from 18x18 3 blade to a 18x17 4 blade would give about the same performance. So the yard is right on removing 1" pitch How is the boat doing now ?
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jhdean
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Re: prop sizing for 36' tri-cabin

Post by jhdean »

The boat is a 1981 . We hit an unmarked shoal on Oneida Lake doing about 5 knots and other than a few paint chips off the keel and the bent props no other damage. I've only had the boat since last Fall and in the process of fixing some minor odds & ends like re-bedding the loose lifeline stanthions
and getting the engine guages working properly. The tachs are very sporadic and now the stbd engine oil preasure guage isnt working which makes me nervous. The engine is full of oil and has low hours since being repowered 4 years ago so I'm pretty sure that its just the guage but need to get that sorted out. Also, would anyone happen to know where the water goes from the drain in the tub in the aft cabins head? I found that the drain in the fwd head was just going into the bilge so Im installiing a proper shower sump below the holding tank but don't see any way to get access to the drain for the aft cabin head. I've had sailboats for over thirty years but this is my first powerboat so any ideas would be greatly appreciated.
Thanks,
John
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P-Dogg
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Re: prop sizing for 36' tri-cabin

Post by P-Dogg »

jhdean wrote: Tue Jul 03, 2018 7:23 am I've had sailboats for over thirty years but this is my first powerboat so any ideas would be greatly appreciated.
Thanks,
John
Well, better late than never.

I have a sump with pump under the floor in front of the aft bed. Appears to be aftermarket.


Wait, the drain for the head, the actual head, or the gray water drain???


Fyi, you can access the tub drain fitting and hose by removing the left inside of the vanity. Or so im told....
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jhdean
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Re: prop sizing for 36' tri-cabin

Post by jhdean »

What Im trying to track down is the drain for the grey water from the tub, on my '81 tri-cabin the vanity under the sink doesnt provide access to it but I havnt torn up the carpet in front of the bet yet.
larryeddington
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Re: prop sizing for 36' tri-cabin

Post by larryeddington »

my 84 has a removable panel on deck at foot of aft bed. It is the overboard for gray water from master bath. Bad thing you have to pull up carpet to get to it.
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jhdean
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Re: prop sizing for 36' tri-cabin

Post by jhdean »

Thanks for the info, I'll pull the carpet and see what I can find.
horhay1946
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Re: prop sizing for 36' tri-cabin

Post by horhay1946 »

On My 81 there is a sump under a hatch at the end of the bed. It drains both the tub and the sink. the sump is basically a small pan with a bilge pump in it. I replaced that with a closed sump. The head goes elsewhere
1985 Mako 258 (One Owner)
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jhdean
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Re: prop sizing for 36' tri-cabin

Post by jhdean »

Thanks,the boat is still on the hard but I should have the new props on and be back in the water by the end of the week and be get in there to see what I have. I already bought a proper shower sump for the Fwd head so will pick up another one for the Aft drain if it doesnt have one in there.
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