Permatrim
- Thread starter Rock-C
- Start date
I am also considering one of these on my Honda 90. I wish there was a way to try one out without drilling a lot of holes in the lower leg.
I expect that it will reduce the need/amount of trim using the tabs, but it might also make the engine trim pretty sensitive.
OTOH, I saw a demo set up of these at the PBIBS. They were on a demo stand, but they did look interesting. Installation seems a lot less involved than conventional tabs.
http://www.zipwake.com/
I expect that it will reduce the need/amount of trim using the tabs, but it might also make the engine trim pretty sensitive.
OTOH, I saw a demo set up of these at the PBIBS. They were on a demo stand, but they did look interesting. Installation seems a lot less involved than conventional tabs.
http://www.zipwake.com/
colbysmith
Active member
After getting several recommendations from other c-brats while at the St. John's gathering, I decided to put a permatrim on my Mercury 115. While purchasing, I found out the USA dealer is Wisconsin's very own Shipyard marina up in Door County on Washington Island. (I've stayed there several times.) Good family business. I just installed mine two days ago, but have not taken the boat out yet. It was a fairly simple/straight forward installation, but did require drilling 10 holes in the cavitation plate of my outboard and in the permatrim. Colby
I installed one 2 seasons ago and like others have said it was pretty straight forward. I permanently sealed the entire permatrim to the cavitation plate with 3M 5200 as I was convinced, after reading here, that the performance would be greatly improved. After only the first trip out, I was pleasantly impressed. The permatrim greatly enhanced the motors ability to stay on step while at slower speed as well as to lowering the bow when needed. What other questions do you have?
There is an abundance of info on the site about this already, and please feel free to discuss your questions on this thread instead of in a PM. Everyone is interested and it's kind of the point of all of this.
The jury is in on permatrim, and it's widely accepted as a great upgrade for anyone. It will very simply increase your boat's responsiveness to it's tilt/trim allowing you greater control of your ride.
CDories are very very very very very sensitive to trim, and your boat's ride will be impacted greatly if you are able to trim the bow down when heading into chop, or trim the bow waaay up when riding in swells or a following sea. Trim tabs are a must, but they can be used for balancing an unevenly loaded boat even more if you have a permatrim doing the heavy lifting on the bow adjustments.
One thing to be conscious of if you are operating both, is to avoid getting the ride just right by having the permatrim and the trim tabs fighting each other. It can sap your efficiency. This can be helpful in some, but very few, situations, but overall can leave you with less ability to control your boat in addition to added fuel cost and reduced range.
So, don't be nervous about those little holes. If you want more bow up/down control, drill those holes and install that permatrim!!
The jury is in on permatrim, and it's widely accepted as a great upgrade for anyone. It will very simply increase your boat's responsiveness to it's tilt/trim allowing you greater control of your ride.
CDories are very very very very very sensitive to trim, and your boat's ride will be impacted greatly if you are able to trim the bow down when heading into chop, or trim the bow waaay up when riding in swells or a following sea. Trim tabs are a must, but they can be used for balancing an unevenly loaded boat even more if you have a permatrim doing the heavy lifting on the bow adjustments.
One thing to be conscious of if you are operating both, is to avoid getting the ride just right by having the permatrim and the trim tabs fighting each other. It can sap your efficiency. This can be helpful in some, but very few, situations, but overall can leave you with less ability to control your boat in addition to added fuel cost and reduced range.
So, don't be nervous about those little holes. If you want more bow up/down control, drill those holes and install that permatrim!!
After 18 years listening to all manner of discussion of hydrofoils and specifically Permatrims, I can't remember any real negative feedback on their performance or advisability.*
They do subtract a mile or two from the WOT speed performance, but make up for it in quicker hole shot, much better trim control, smoother running through chop, better gas mileage, less ventilation on tight turns, and more that I can't remember right now.
Yes, it causes one to wince a bit when thinking of drilling those holes.
I like the idea of using 5200 to seal up the space between the plates, but the real drag probably comes with the bolt heads and nuts, which I wouldn't remove any of without talking to Andy Munao at Shipyard Island Marine, the sole US Permatrim dealer.
What's not to like?
Joe. :teeth :thup
*"40 Million Frenchmen Can't Be Wrong." :lol:
They do subtract a mile or two from the WOT speed performance, but make up for it in quicker hole shot, much better trim control, smoother running through chop, better gas mileage, less ventilation on tight turns, and more that I can't remember right now.
Yes, it causes one to wince a bit when thinking of drilling those holes.
I like the idea of using 5200 to seal up the space between the plates, but the real drag probably comes with the bolt heads and nuts, which I wouldn't remove any of without talking to Andy Munao at Shipyard Island Marine, the sole US Permatrim dealer.
What's not to like?
Joe. :teeth :thup
*"40 Million Frenchmen Can't Be Wrong." :lol:
Thanks for all the help folks, They were looking for some measurements.
I will post them here in case anyone ever needs them again. Take a good look at a photo to interpret the dimensions below.
I measured our model which is on a 2003 honda 75 which would be the same at the carbed 90hp model as well.
-1/4 inch thick aluminum is the material used
-Total length 21.5 in
-Total width 12.5 in
-Folded depth of sides 2 in (so the pre-bent width would be 16.5)
-length of folds are 12 inches starting at rear and taper at the front 4 inches
-Length of mounting slot 14.25 inches
-Width of mounting slot is 2.5 in until the last 3 inches where is starts to taper down to 1.5 in
-The leading front "points" are tapered down from the 12in (from back) mark to 2 inches and rounded.
Ours are mounted with (4) 1/4 inch thick bolts on each side with nuts on the top and some sealant between the plate and outboard
Greg
I will post them here in case anyone ever needs them again. Take a good look at a photo to interpret the dimensions below.
I measured our model which is on a 2003 honda 75 which would be the same at the carbed 90hp model as well.
-1/4 inch thick aluminum is the material used
-Total length 21.5 in
-Total width 12.5 in
-Folded depth of sides 2 in (so the pre-bent width would be 16.5)
-length of folds are 12 inches starting at rear and taper at the front 4 inches
-Length of mounting slot 14.25 inches
-Width of mounting slot is 2.5 in until the last 3 inches where is starts to taper down to 1.5 in
-The leading front "points" are tapered down from the 12in (from back) mark to 2 inches and rounded.
Ours are mounted with (4) 1/4 inch thick bolts on each side with nuts on the top and some sealant between the plate and outboard
Greg
Greg, thanks again for your quick reply. The information is just what I was looking for. As i said in a PM, my son works at a fab shop & I'm going to have one made locally. I have had Dolphins on the motor but was never satisfied with the performance. BTW, I have a free set of Dolphins if anyone is interested. I can bring them to Friday Hbr.
Rock-C - my brother & I have built three permatrim type of foils using 1/8“ aluminum. Never had a problem with any. One was for a 50hp Honda on my 16 cruiser one for a 90hp Honda for a friend & the third for a 90hp Evinrude on the original Marinaut. I can use it as a step without it bending. A template & photo for my 16/18 cruiser is HERE.
1/8“ material will cause much less drag & is more than strong enough. I did not notice a loss of speed with my 16/18 & the Marinaut was so slight it was hardly noticeable. Maybe 1/2mph but then again conditions could have been the reason for the change.
Dave
1/8“ material will cause much less drag & is more than strong enough. I did not notice a loss of speed with my 16/18 & the Marinaut was so slight it was hardly noticeable. Maybe 1/2mph but then again conditions could have been the reason for the change.
Dave
Ferg":2dvi0fr9 said:
I would ask your dealer, how much time he has spent cruising these boats and in what type of conditions. It is the general consensus of hundreds of owners that it makes a significant difference in the handling. I have tried the 22 without any foil, with trim tabs alone and tabs plus foil. The latter is best. The 25 had trim tabs when I purchased it, and I used the boat for a season without a Permatrim, and then added it. Definite improvement in handling.
If the foil is properly installed and trimmed, it should make little if any difference in the top speed or MPG (might even increased the MPG). The foil should run just on top of the water at planning speed.
There are other foils which a few have used, including "Bob's Machine ship".
Appreciate the replies to my comment, I'm not taking a position, I'm just giving his....but he's a well respected guy.
But I do wonder that if they do improve performance, why haven't the manufacturers incorporated that into their designs.
Honest, I don't have a dog in this fight, I'm just kinda confused
But I do wonder that if they do improve performance, why haven't the manufacturers incorporated that into their designs.
Honest, I don't have a dog in this fight, I'm just kinda confused
Ferg":2dmf6zhk said:
I don't think they work well on all boats, especially deep V hull shapes, as the motor is often much farther down in the water, often with its anti-cavitation plate fully submerged on step for example creating more drag than we see. And they do add drag, which some would see as a negative compared to the benefits on their boat, and they are very easily added to an outboard.
I really think they make the best improvement with the fewest sacrifices in flatter bottom, heavier (for size) planing hulls like ours. I think manufacturers would be foolish to make this a standard, and are generally very concerned with reducing the drag of their lower units as much as possible from a design standpoint. In other words, it is vastly easier to drill some holes and bolt on a permatrim than it would be to cut down a huge anti cavitation plate to reduce its drag.
Everything in a boat is a tradeoff. The permatrim essentially adds a little bit of rudder effect to the thrust vector that allows you to trim your bow up/down, while simultaneously holding more water near your prop with less exposure to the air, reducing cavitation. If your boat already trims nicely, and doesn't have any cavitation issues, the extra drag is probably not worth it (and those holes in the anti cavitation plate definitely are not!). There may be aspects of the permatrim's performance that I'm not familar with and haven't addressed, but I'm sure if I've missed something someone else will catch it (usually Dr. Bob)!
colbysmith
Active member
Another aspect that may be important, and was pointed out in the online instructions for mounting the Permatrim, is position of your engine. The ideal position puts the cavitation plate just about level/even with the bottom of your hull. This is where the Permatrim works best. (According to various sources.) Colby
Dave, thanks for the photos. You did a good job on that hydrofoil. Im going to use marine grade alloy, 6061 or something similar. I hope to run into you this summer and get caught up on your latest adventures. BTW, I just purchased a Suziki 2.5 to replace the Honda 2. Inmar marine had the best price & free shipping. Thank to all that replied to my original post.