# Compression plates for flat bottoms?



## johnstonblake (Jul 7, 2015)

I have a 15' aluminum flat bottom (no tunnel) with float pods/sponsons, 25 hp Yamaha four stroke, and a trim unit that doubles as a manual jack plate. I'm wanting to get the motor as high as possible and was wondering if a plate would help. Any suggestions on a compression plate or hydrofoil?


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## Smackdaddy53 (Dec 31, 2012)

Yes, a Tran plate will do wonders for you. Order one from Tran Sport Boats in Palacios Texas.


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## topnative2 (Feb 22, 2009)

getting it to high could be dangerous on turns and rough water


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## Blackdog317 (Jun 20, 2015)

I had a Shaw Wing on my Ranger Banshee Extreme (flat bottom). It made a big difference on how high I could run the motor. I have a Tran Plate (small HP model) on my BT Mosquito - 2° deadrise at the stern...basically flat. Huge improvement as well.


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## permitchaser (Aug 26, 2013)

I have a Bob's compression plate sitting in the garage with the SS nuts and bolts .It came off the original engine .I know it will help just don't want to drill six holes to attach it


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## Smackdaddy53 (Dec 31, 2012)

permitchaser said:


> I have a Bob's compression plate sitting in the garage with the SS nuts and bolts .It came off the original engine .I know it will help just don't want to drill six holes to attach it


That plate is more like a hydrofoil for planing purposes, a compression plate curves around the prop and holds water so your prop does not cavitate. The few guys that took my advice on the Tran plates were not disappointed. Shaw wings look silly with all the bolts in my opinion but you don’t have to drill through the motor cavitation plate. I’d go with a Tran and drill the holes. They are solid!


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## Smackdaddy53 (Dec 31, 2012)

topnative2 said:


> getting it to high could be dangerous on turns and rough water


Common sense goes a long way.


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## topnative2 (Feb 22, 2009)

But, it is uncommon these days......especially when a lot of folks are overpowering their skiffs


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## Str8-Six (Jul 6, 2015)

What are the thoughts of running compression plate on sponson skiff/flat bottom without jack plate? Also if boat likes to ride bow down naturally is it possible that a compression plate can force stern too high on certain skiff designs? Creating risk of stuffing bow in certain conditions. Just wondering.


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## Smackdaddy53 (Dec 31, 2012)

Str8-Six said:


> What are the thoughts of running compression plate on sponson skiff/flat bottom without jack plate? Also if boat likes to ride bow down naturally is it possible that a compression plate can force stern too high on certain skiff designs? Creating risk of stuffing bow in certain conditions. Just wondering.


You’re overthinking it. Anything is possible but how many hulls ride bow down and you have to figure out how to get more weight near the stern? It’s not many, that’s one of the main reasons you see all these skiffs with trim tabs and fuel tanks and batteries in the bow.


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## Str8-Six (Jul 6, 2015)

Smackdaddy53 said:


> You’re overthinking it. Anything is possible but how many hulls ride bow down and you have to figure out how to get more weight near the stern? It’s not many, that’s one of the main reasons you see all these skiffs with trim tabs and fuel tanks and batteries in the bow.


Lol I should have been more specific. My boat rides bow down and I’m worried about this issue. I want to raise motor a bit and avoid cavitation. Assuming I will lose some RPMs by adding cavitation plate but gain a little from raising motor correct? Thanks smack!


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## Smackdaddy53 (Dec 31, 2012)

Str8-Six said:


> Lol I should have been more specific. My boat rides bow down and I’m worried about this issue. I want to raise motor a bit and avoid cavitation. Assuming I will lose some RPMs by adding cavitation plate but gain a little from raising motor correct? Thanks smack!


A compression plate shouldn’t make you lose speed, you should actually gain a little because it makes your prop rotations more efficient. I gained 2-3mph in shallow water with it and stayed about the same in deep water crossing the bay. The same goes with trim tabs GENERALLY SPEAKING. They are adjusting the attitude of your boat and I actually could not run 33-34mph without tabs because when I “air it out” and trim my motor out I need just a little tab down to get the bow down at WOT. Of course if you go trying to run with the tabs all the way down all the time it will make your bow plow and you can’t do anything BUT if you lower both tabs all the way to perform a straight hole shot and lift tabs and trim out at the same time as you get on top you can jump up very well.


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## Sandalous (Oct 30, 2013)

I just put a Bob's plate on my flat bottom boat, and have been very impressed with it. I gained a little bit of top end, the boat jumps up faster, it feels much better in turns and running in general, I can run my jackplate up much higher without the prop cavitating, and I don't have to use the tabs as much to keep the bow down when I'm running with a lot of weight in the back. Also, the side fins on the plate are large enough to counteract most of the prop torque, so I was able to cut the trim fin off of my zinc. Getting the plate and a cupped propeller were two things that I wish I would have done much sooner. It feels like I am running a different boat.


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## Matts (Sep 2, 2015)

I bought the large compression plate from Boatright Marine, back when I had a really, really tricked out Weld-Craft (sponsons, jack plate, large tunnel and 4 blade prop). The compression plate made a HUGE difference in being able to run with the motor way up high but I'm not sure how that would work without the tunnel funneling water to the prop. Glen Boatright nows how to rig an aluminum boat and has the plates for sale. He does exceptional rigging, flooring, etc.

http://boatrightmarine.com


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