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Old 10-07-2020, 19:53   #1
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Jackplates on cat?

Does anyone have experience or opinion as to installing jackplates to raise and lower outboard engines on a catamaran?
Doing refit on OB engines. Currently engines on Crowther 46’ are Yamaha T9.9s with extra long 25” shafts. Headwinds and slow speed manoeuvring against stronger gusts makes me want more power. Refitting the boat with Yamaha T25X (high thrust extra long shafts). Not sure if original design was rigged for 25hp weighing 154.8 lbs. That got me thinking about reinforcing the pods that hold the motors With an aluminum backing plate. Research led me to the option of jackplates with instant electro/hydraulic lifts to replace the pods. Bolted straight onto the large aft aluminum cross tube, the jackPlate would have plenty of support and allow me to raise and lower the 25” shaft OB as much as an extra eight inches. This would seem to be perfect for choppy conditions where the props needed a little height adjustment. It would also allow me to raise the engines clean out of the water with the help of th engine tilt function. Boat goes about two knots faster Under sail with both engines clean out of the water. Has anyone tried this? Does anyone have recommendation as to a brand of jackplates? Setback on the jackplates would be minimal (4”) and the vertical lift seems ideal. Thoughts? Thank you.
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Old 11-07-2020, 14:10   #2
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Re: Jackplates on cat?

I have a pivoting mount for my Yammie 25 high thrust. It works really well. I am on holidays now but can send pics in a few days
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Old 11-07-2020, 14:51   #3
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Re: Jackplates on cat?

Quote:
Originally Posted by catsketcher View Post
I have a pivoting mount for my Yammie 25 high thrust. It works really well. I am on holidays now but can send pics in a few days
Thanks very much! Would appreciate seeing your engine setup. Enjoy your vacation.
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Old 11-07-2020, 15:16   #4
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Re: Jackplates on cat?

I have custom built jack plates on my 50’ cat that allow the motors to come clear of the water AND higher enough that you can service them on the boat while sitting on the aft transom steps.

I highly recommend them, but can’t steer you toward a brand.
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Old 11-07-2020, 15:27   #5
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Re: Jackplates on cat?

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Originally Posted by Chotu View Post
I have custom built jack plates on my 50’ cat that allow the motors to come clear of the water AND higher enough that you can service them on the boat while sitting on the aft transom steps.

I highly recommend them, but can’t steer you toward a brand.
Thanks for the affirmation. And the concept of fully raising them vertically out of water For service is a great idea. None of the jackplate manufacturing techs I spoke with had any prior knowledge of a cat using them. - bass boats mostly. Of course New England isn’t exactly catamaran country - yet. My boat has pics at OceanZenSailing on Instagram and website by same name. She is still a work in progress but loving the boat even as is.

Would you be able to send me a pic of the custom plate so so I could consider the design? Truly appreciated.
Jim
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Old 11-07-2020, 15:42   #6
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Re: Jackplates on cat?

Quote:
Originally Posted by JimmyDarci View Post
Thanks for the affirmation. And the concept of fully raising them vertically out of water For service is a great idea. None of the jackplate manufacturing techs I spoke with had any prior knowledge of a cat using them. - bass boats mostly. Of course New England isn’t exactly catamaran country - yet. My boat has pics at OceanZenSailing on Instagram and website by same name. She is still a work in progress but loving the boat even as is.

Would you be able to send me a pic of the custom plate so so I could consider the design? Truly appreciated.
Jim
Sure! If you can send me a dm with your email, I’ll send you over the details of the installation.

Mine are raised manually for simplicity and reliability.
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Old 17-07-2020, 02:55   #7
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Re: Jackplates on cat?

Here are the pics of my cat. The motor is a 25 hp Yamaha four stroke. I really like the set up. It is bulletproof and protects the outboards very well. The outboard has its tilt unit removed. I laminated a tube into the nacelle to receive the outboard's tilt bolt. The bottom end is held down by lashings.

Your boat looks like it may already have a moving engine pod. If you post some pics we may be able to work out a good solution. The 9.9s are way too small for such a large boat. Twin Yammie 25s would be a much better option.

cheers

Phil
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Old 17-07-2020, 03:55   #8
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Re: Jackplates on cat?

Quote:
Originally Posted by catsketcher View Post
Here are the pics of my cat. The motor is a 25 hp Yamaha four stroke. I really like the set up. It is bulletproof and protects the outboards very well. The outboard has its tilt unit removed. I laminated a tube into the nacelle to receive the outboard's tilt bolt. The bottom end is held down by lashings.

Your boat looks like it may already have a moving engine pod. If you post some pics we may be able to work out a good solution. The 9.9s are way too small for such a large boat. Twin Yammie 25s would be a much better option.

cheers

Phil
With your rotating outboard mount nacelle, do you have a downhaul to hold it in place? If not, is the weight enough to keep it from swinging up in waves?

We're in the process of finalizing design plans for a new cat and the designer wants to mount the outboards in the typical nacelle pods like on the Seawind. I'd prefer more clearance with the outboards raised, and something similar to your design - not unlike the kick-up rudder box already designed- would work great... if we have space above. Thanks for posting the photos.

Matt
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Old 17-07-2020, 03:55   #9
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Re: Jackplates on cat?

A typical Jack plate as used on a bass boat has 5 inch of lift. I have seen custom-made plates with double that lift but cannot direct you to a manufacturer either. Perhaps contact CMC. As they are a manufacturer of jack plates and have a decent website
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Old 17-07-2020, 04:18   #10
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Re: Jackplates on cat?

Quote:
Originally Posted by funjohnson View Post
With your rotating outboard mount nacelle, do you have a downhaul to hold it in place? If not, is the weight enough to keep it from swinging up in waves?

We're in the process of finalizing design plans for a new cat and the designer wants to mount the outboards in the typical nacelle pods like on the Seawind. I'd prefer more clearance with the outboards raised, and something similar to your design - not unlike the kick-up rudder box already designed- would work great... if we have space above. Thanks for posting the photos.

Matt
We had similar on our gemini...in forward, it's not an issue. The weight of the motor plus the forward rotational force from the prop keeps the motor down but it also lifts on extreme waves limiting the risk to swamping the engine.

In reverse, if you gun it, it will lift the sled a bit. It was never a big issue though I'm sure it wouldn't be hard to add something to hold it down for docking.
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Old 17-07-2020, 04:42   #11
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Re: Jackplates on cat?

Yes there is a downhaul for reverse. This is the third try of pods for our cat and by far the best arrangement for us. Some cats have clever use of the chamfer panel but I love how quietly our boat now sails in waves with absolutely no banging on the pods. Also the motors are really well protected when sailing.

This is really like the Seawind system but with the entire pod rotating, rather than just the mount within the pod.

cheers

Phil
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Old 18-07-2020, 07:58   #12
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Re: Jackplates on cat?

Here’s our pod setup on the TRT. Works well but doesn’t protect the motor nearly as well as Catsketchers.
Notice the high tech downhaul!
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Old 18-07-2020, 09:06   #13
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Re: Jackplates on cat?

Quote:
Originally Posted by smj View Post
Here’s our pod setup on the TRT. Works well but doesn’t protect the motor nearly as well as Catsketchers.
Notice the high tech downhaul!
Attachment 219556Attachment 219557Attachment 219558

Thanks for posting these. I now need to see if we'll have enough clearance to accommodate something similar.

So unlike Catsketcher's set-up, you still use the tilt function of the outboard to raise it fully? What is the sequence for raising and lowering the outboards and pods?

Thanks,

Matt
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Old 18-07-2020, 10:17   #14
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Jackplates on cat?

Quote:
Originally Posted by funjohnson View Post
Thanks for posting these. I now need to see if we'll have enough clearance to accommodate something similar.



So unlike Catsketcher's set-up, you still use the tilt function of the outboard to raise it fully? What is the sequence for raising and lowering the outboards and pods?



Thanks,



Matt


You can raise the outboard alone leaving the pods down, raise the pod only which will leave the lower unit slightly exposed but well clear of the water or a combination of both which does a good job of reducing the chances of either pod or lower unit coming into contact with the water.
I usually just raise the pod unless weather and chop are bad as it doesn’t put any undo stress on the shift and throttle cables.
BTW, have you made a decision on which catamaran to build?
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Old 18-07-2020, 10:57   #15
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Re: Jackplates on cat?

Quote:
Originally Posted by smj View Post
You can raise the outboard alone leaving the pods down, raise the pod only which will leave the lower unit slightly exposed but well clear of the water or a combination of both which does a good job of reducing the chances of either pod or lower unit coming into contact with the water.
I usually just raise the pod unless weather and chop are bad as it doesn’t put any undo stress on the shift and throttle cables.
Sounds like a pretty versatile package! I hadn't thought of the articulation effecting the throttle and shift cable. Thanks for the added info

Quote:
Originally Posted by smj View Post
BTW, have you made a decision on which catamaran to build?
Not 100% yet. We have a few new options- quite different- that have made the decision that much more challenging. And COVID has screwed the process up since we are unable to travel to completed boats, fall in love, and make the decision based on which felt right. We now have to think practically and use data for the decision. What fun is there in that?

We're first trying to figure out build location. I have realtors scouting sites all along the East Coast, but tight budget is killing most good options. As soon as that's found, then we'll make the final decision and place the order. Hopefully in the next month or so.

Matt
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