20 foot Hourston prop recommendations?

[Squire]

manual says wot should be 5500-6100 rpm’s. The cavitation plate is dead level with the bottom of the hull. Its mounted 2nd hole from the top. How much higher can the cavitation plate be from the bottom of the hull?

The position of the cavitation plate relative to the bottom of the hull is just a starting point. You need to get up on step and have someone take a picture, or even better a video, of the lower leg in the water. The cavitation plate’s ideal position is just skimming along the top of the water. It should be touching but not buried.
Beautiful boat; it can be a frustrating process but once you get it dialled in it is very satisfying knowing you are optimizing your boat’s performance.

 

[Max123]

Agreed with other comments, motor looks low. I suspect the anti-cavitation plate is buried at speed.

Not sure how the pod is designed/attached to the hull - is it a hull extension, tapered, stepped at hull? You say the anti cavitation plate is level with the underside of the pod - but is that when the trim is bottomed out, or trimmed so the motor is perpendicular to underside? In either case, if this were a dead flat hull extension pod, you would want the leading underside edge of the anti-cav plate to be minimum 1" above the underside of hull for every 12" of setback when the motor is trimmed correctly (not bottomed out). For stepped/tapered pods, likely even higher.

The way you test is to get it up to cruising speed (not max/WOT), trimmed properly, and then look over the transom and see if the you can see the anti-cavitation plate skimming the surface of the water. If its buried - its way too low, and its pointless to start messing around with props till you fix the mounting height.

 

[Aquaholic]

Don't be discouraged by having to tinker with props and potential engine height adjustments. Almost every pod thread on here has gone through a similar trial and error. Once you find the sweet spot for both, you will be happy.

 

[Gallivanter]

I run a 3x16x20 on my Zuke 200, 5300rpm @WOT , I’m in a 22’ tin boat so might be a bit lighter then a 20’ Hourston. My average weight of my boat while fishing/travelling is 5100lbs and pretty happy with the motor/prop performance. As others are saying my motor looks to be mounted higher then yours with relation to your pod/hull, but it’s hard to tell for sure from pictures.

 

[Doubleheader]

If I drop my motor two bolt holes I lose a whopping 2mph wot. It’s a planing pod on that rig, anywhere close to level with the keel with the correct prop you would see sufficient rpm. Find the correct prop before tinkering with anything else imo. These boats are a lot different than an aluminum to get up and keep up.

 

[Max123]

As a side note, check to make sure the tach is setup correctly. On certain tachs there is a switch on the back that changes the setup. 4000rpm seems almost unbelievably low.

Just thought i'd mention it - this comes up occasionally.

 

[My boy blue]

It’s a digital Suzuki gauge so I’ll mention that info to the dealer tomorrow. Hopefully get a test prop put on this week and take it for another go this weekend. I’ll make sure to get a video of the back to record if it’s got any spray.

 

[salmonkiller01]

Suzuki’s swing large diameter props. I would say a 14 or 15 pitch if sticking with 16”diameter.
Nice boat. Is that the one from sooke?

 

[Squire]

It’s a digital Suzuki gauge so I’ll mention that info to the dealer tomorrow. Hopefully get a test prop put on this week and take it for another go this weekend. I’ll make sure to get a video of the back to record if it’s got any spray.

It should look like this:


Not this:

 

[My boy blue]

Issue solved, Suzuki grommet had the throttle cables pinched and it wasn’t allowing the cable to engage fully (even though shifter would go full distance). Swapped out to a hollow grommet and it works great. Prop size ended up being 16x21.5.