View Full Version : Prop Size

07-22-2014, 05:24 AM
I purchased a 1988 39' Holiday Mansion Coastal Barracuda a couple of years ago and am unsure if I have the best pitched props for it. It has twin crusader 350 engines with inboards. Love the boat.

Most of the Holiday Mansions that I come across have I/O so I haven't been able to reference properly what the propeller size should be.

When I purchased it, the boat had major propeller damage and from what I could tell had 18x18 3 blade propellers on it. Does anyone know where I can reference what the proper size propeller for this?

08-12-2014, 07:36 PM
My 1986 Coastal Barracuda has 18" diameter by 16" pitch, 3 blade props. Dual Crusader 270hp 350ci engines with 1:1 Vee Drives. I am thinking about knocking 1/4" of pitch off of the props because I have plenty of WOT, around 4,700 rpms to be exact. If I knock 1/4" - 1/2" off the pitch I might be able to get more top end without over revving the engines. I'd like to keep my WOT around 4,250.

10-28-2014, 07:09 PM
Hey stp - I'm no expert, but isn't that backwards? If you want to knock down your WOT, you would want to increase pitch. I looked it up - found this:
"If you're changing pitch on a recreational boat, remember that each inch of pitch is worth about 200 rpm. Lowering the pitch will increase rpm and vice versa. For example, going from a 23 pitch to a 21 pitch will increase engine rpm by about 400 revolutions."

BTW, I have a 1986 37' aft cabin with twin Merc 230's (305) and V-drives. 18x16 3 blade props. Not sure about the trani ratio, but guessing it would be a slightly higher ratio due to the lesser HP since we have the same props.

10-29-2014, 04:36 AM
Yes, that was a typo. Just curious, what's your WOT? I'd imagine you're right about your tranny ratio. Your boat should also be a bit heavier than mine with the aft cabin.

10-29-2014, 02:15 PM
WOT is supposed to be 4400. I can only hit that if the boat actually gets on plane, otherwise the drag is too high - so the max I get is about 4100. Yes the boat is very back heavy. We also have a genny back there. My hunch is that HM never intended this hull to carry the aft cabin, twin engines, and a generator in the back. I'm thinking about adding a 2-3' hull extension under the swim platform to compensate. That should make planing easier and the boat should sit in the water more level.

10-29-2014, 05:54 PM
That would be an ambitious project. There's one on Boattrader that was converted to outboards with jack plates. Not really a good solution for you since you'd lose the swim platform, but it's a neat modification nonetheless:


There's another HM that was listed recently with an Awlgrip paint job. I can't imagine what something like this would cost!


10-29-2014, 07:54 PM
Looks like we're scoping out the same stuff. I have that triple outboard link saved as well. The mechanicals and electrical on that boat are fantastic - but totally insane! There's a thread about it here:

Nice windlass - and of course that's where it wants to go. But it kills the front deck area. If I do it, I'll probably put it off to the port side as inconspicuously as possible. I have a LOA problem in our marina and can't add another foot to the length. I can get away with it under the swim platform because that's already part of the LOA.

10-29-2014, 07:57 PM
Here's the craziest HM mod I've seen to date: http://www.powerboatlistings.com/view/13154http://www.powerboatlistings.com/view/13154

10-30-2014, 01:01 PM
Interesting idea to put the windlass off to the side. I'm probably going to put mine dead center. I have the sea package so I'll probably mount the windlass right to the deck and run an anchor roller through the sea package. Biggest issue I anticipate is not being able to see the anchor or the roller. I'm going to investigate mounting a camera at the bow and a glare free screen on the bridge so I can see the anchor. Finding a screen that you can read in direct sunlight may be a challenge.

10-30-2014, 01:12 PM
Roger that.