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Author Topic: Transom Wedges?  (Read 1039 times)

September 19, 2010, 10:13:22 AM
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akbridge

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Transom Wedges?
« on: September 19, 2010, 10:13:22 AM »
Has anyone tried them on an older AS?  On my 170 I have an old johnson V4 90 mounted on a jackplate.  With the prop that I have and the extra stern weight I have a hard time keeping the front of the boat down (the boat wants to porpoise).  I would like to put on trim tabs and a stern lifting four blade prop.  But money is tight with the young one and wife not working.  So I thought that transom wedges might be able to help.  Most of the time the boat does great.  But in a strong head wind I want to push the bow down more to prevent some of the slamming into the next wave.  Also I would like to lower my plane speed.  Currently I can keep it on a plane at 18 mph.  But I have to keep the jackplate as low a possible and be ready on the controls because a good wave could knock me off a plane.

September 19, 2010, 11:04:41 AM
Reply #1

John Jones

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Re: Transom Wedges?
« Reply #1 on: September 19, 2010, 11:04:41 AM »
I have always considered wedges more for a quick shallow hole shot than anything else.  If you are already trimmed all the way down and it's still porpoising then more negative trim might help and wedges are probably the cheapest way to go.  My son has them on his Mitzi 17 and they did help his hole shot a bit but once you trim up a little they do nothing.

I had a 19' Key West that would porpoise with just a little trim up and also would not turn if trimmed up.  A Bob's stabilizer plate made a world of difference with both issues.
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September 19, 2010, 01:58:34 PM
Reply #2

fitz73222

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Re: Transom Wedges?
« Reply #2 on: September 19, 2010, 01:58:34 PM »
Hey Akbridge,

One less costly idea that works very well for me on my old Orlando Clipper skiff is a pair of Smart Tabs. These are gas charged cylinders and stainless trim plates. My old clipper had a wild porpoise and poor load carrying performance with a 9.9 Merc. You buy them based on the amount of stern lift you need using their calculator. The theory is that they keep the bow down with upward stern force on the transom and collapse as speed increases while maintaining the lift. The boat went from barely planing two people to planing three at lower speed and the porpising completely went away and my top speed increased to 22 mph with one person; which is pretty respectable with only 10 hp. They sell for about $129. for a set. I talked a friend of mine at work into a pair of them for his 17 ft Islander and he loves them! With these on your boat, you can keep your engine trim level, increase the holeshot, remove the porpoise and not loose any top speed or actually increase top speed without having the boat in a constant bow steer situation from too much stern lift. I swear by them.
1973 Aquasport 22-2, twin 115 Mercs
2000 Baycraft 175 flats boat, 60 Bigfoot Merc
1968 Boston Whaler 13, 25 Yamaha (project)
1966 Orlando Clipper 13, 9.9 Merc

September 19, 2010, 02:42:02 PM
Reply #3

seabob4

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Re: Transom Wedges?
« Reply #3 on: September 19, 2010, 02:42:02 PM »
Smart Tabs DO work!  You definitely want to play with the mounting holes, and once you get them dialed in for holeshot and porpoising, then play with the prop pitch for topend...straight from the pres of Nauticus...


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September 19, 2010, 05:11:11 PM
Reply #4

akbridge

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Re: Transom Wedges?
« Reply #4 on: September 19, 2010, 05:11:11 PM »
Thanks for the input folks.  I have thought about smart tabs.  The only problem is I have bait boxes hung off the boat.  And I don't wanna hang tabs off the back.  When my boat is running at speed (30+ mph) the water doesn't touch the bottom of my boxes.  When I added the boxes it did not change the tendency to porpoise.  Just in case you are wondering.
My holeshot is awesome.  I don't need any help there.  I already almost throw the dog out of the boat now and then :shock:  
I am just trying to keep the bow down when running with my jackplate all the way up and when running WFO.

 


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