Wishing everyone a good start to the boating season from northeast Washington on the Columbia River. I have been reading the posts on various methods/equipment to achieve a plane at lower speeds. I installed the SE sport 400 on my 90 HP Honda. I have a 2000 22’ Cruiser. It did nothing but create more drag. I would like to avoid trim tabs. I mostly cruise at 8-10 mph. From looking at a graphic of the Permatrim it does not look much different than the SE sport yet the reviews here are mostly positive. What do you old salts say to this?
Poor planning on my 22’ cruiser
- Thread starter Kingmann
- Start date
T.R. Bauer
New member
I bought these and are very happy with them as they really get the bow down... https://www.amazon.com/Davis-Instrument ... B001QUS4JM
BTW, all of these probably make more drag.....since you are lifting the stern with the foil.
BTW, all of these probably make more drag.....since you are lifting the stern with the foil.
I'm not familiar with the SE sport 400 - other than to look at it online but I did put permatrims on my twin Honda 40's when I had a CD 22 and I have permatrims on my twin Honda 130's on my Tomcat. With the permatrims, there is a bit of added drag (after all, one is using the pressure of the moving water to push the stern up and the bow down). I lost about 1-2MPH in top end speed on my 22. I gained a much smoother ride and the boat got on plane much more quickly. I thought it was a good trade-off for the way I used the boat - mostly for fishing and often in rough water off the coast of WA. From the looks of the SE sport 400, the surface area appears to be lower than a permatrim. Also, the SE sport 400 is made of plastic and I'm guessing it flexes a bit and that would affect it's lifting ability.Kingmann":3je4sts9 said:
My experience with Permatrims is much like Rogers. We have the addition of trim tabs too & like the combination, especially where we run such a varying weight from extremely heavy to semi lite. The combination really helps in the ride & getting the best performance out of the boat.
Your choice of speed is right where a C-Dory 22 performs at its very worst, except for some wind & wave combinations. You are running at a speed just between displacement & on plane. Makes for poor milage, but have found it useful, like I said previously in some sea conditions, but not a good speed for most conditions or performance. If you really want to continue running normally at this speed then the Permitrims or in combination with trim tabs will get the bow down more & even with their increased drag by leveling out the boat will improve the ride & maybe even the milage. I know it did for us when I was extremely overloaded in the stern & still wanted to run on plane, but that was at a speed of at least 12 to 14 mph.
Jay
Your choice of speed is right where a C-Dory 22 performs at its very worst, except for some wind & wave combinations. You are running at a speed just between displacement & on plane. Makes for poor milage, but have found it useful, like I said previously in some sea conditions, but not a good speed for most conditions or performance. If you really want to continue running normally at this speed then the Permitrims or in combination with trim tabs will get the bow down more & even with their increased drag by leveling out the boat will improve the ride & maybe even the milage. I know it did for us when I was extremely overloaded in the stern & still wanted to run on plane, but that was at a speed of at least 12 to 14 mph.
Jay
Agree 100% with Jay. You are attempting run the boat at the speed where it is attempting to drive over the bow wave and come on a plane. A plane breaks the suction. of the hull in this wave, and is far more efficient. If you want the best economy keep the speed below 6 knots There is a break even point and that may be somewhere below 5 knots--and the boat becomes slightly less effect. That is hard to measure because of difficulty of accurate fuel measurement by most turbine type of sensors at flow rates of less than one gallon of fuel an hour.
The trim tabs will help to plane at lower speeds, they also will help getting the bow down having a good ride, by pushing the "V" of the hull into the chop.
The Permatrim has proven to. be the best of the foils (I cannot comment on the Davis one T.R. Bauer has used. When running properly with the foil on top of the water there is very little increased drag. If the motor is too low in the water, then yes. My last 22 had a "Doelfin" plastic fin--it was somewhat effective, but not as good as the Permatrim. It is very similar to the "Drilless" one used by the OP. Both of these have vertical ribs--I don't see where they add anything to lift--they are there to attempt to decrease the flex of a plastic. Thus create more drag.
My advice--don't try and run at 8 to 10 knots. Even for a 40 foot trawler or 62 foot sailboat that is a bad speed. Try and stay down near the sq rt of LWL (about 19' and speed of 4.3 knots (5 mph, which is often given as a "no wake" speed.). If. you exceed 1.34x sq tr LWL (5.8 knots or 6.7 mph) you will be in a very in efficient speed zone. On my current 25 the worst mileage is between 8 and 12 knots, it is very noticeable in my fuel consumption curves. The Permatrim and tabs make little difference, except then can slightly lower the planing speed and definitely get on the plane faster.
The trim tabs will help to plane at lower speeds, they also will help getting the bow down having a good ride, by pushing the "V" of the hull into the chop.
The Permatrim has proven to. be the best of the foils (I cannot comment on the Davis one T.R. Bauer has used. When running properly with the foil on top of the water there is very little increased drag. If the motor is too low in the water, then yes. My last 22 had a "Doelfin" plastic fin--it was somewhat effective, but not as good as the Permatrim. It is very similar to the "Drilless" one used by the OP. Both of these have vertical ribs--I don't see where they add anything to lift--they are there to attempt to decrease the flex of a plastic. Thus create more drag.
My advice--don't try and run at 8 to 10 knots. Even for a 40 foot trawler or 62 foot sailboat that is a bad speed. Try and stay down near the sq rt of LWL (about 19' and speed of 4.3 knots (5 mph, which is often given as a "no wake" speed.). If. you exceed 1.34x sq tr LWL (5.8 knots or 6.7 mph) you will be in a very in efficient speed zone. On my current 25 the worst mileage is between 8 and 12 knots, it is very noticeable in my fuel consumption curves. The Permatrim and tabs make little difference, except then can slightly lower the planing speed and definitely get on the plane faster.
I run twin 40's on a 22 Cruiser equipped with trim tabs. I have resisted the Permatrim application, only because the trim tabs do much of what the Permatrims do. For me that is getting the bow down into the chop, and help getting leveled on plane quicker.
I think the Permatrims will do the same and very effectively especially on twins, providing some lateral trim ability as well. Pretty sure the Permatrims do provide an advantage in low speed directional control over trim tabs.
From the Amazon/Davis web site.
You are running a single 90hp OB, with no trim tabs, I think the obvious way to go would be with the proven Permatrim. That will give increased ability to drive the bow down in chop and get onto plane at a lower speed. Totally agree that the 6-10 mph is the most inefficient speed to run the C-Dory at.
Harvey
SleepyC :moon
I think the Permatrims will do the same and very effectively especially on twins, providing some lateral trim ability as well. Pretty sure the Permatrims do provide an advantage in low speed directional control over trim tabs.
From the Amazon/Davis web site.
The difference will be in the surface area. Pretty sure the Permatrim will have a greater square inch number, which is the working surface difference.
You are running a single 90hp OB, with no trim tabs, I think the obvious way to go would be with the proven Permatrim. That will give increased ability to drive the bow down in chop and get onto plane at a lower speed. Totally agree that the 6-10 mph is the most inefficient speed to run the C-Dory at.
Harvey
SleepyC :moon
I agree completely with Jay, Bob, Harvey, and Roger on the usefulness of Permatrims. Ditto on the inefficiency of "in-between" speeds.
With Permatrims on twins, I found no need for trim tabs. With a single, I would consider using both.
One thing to check carefully is the mounting height of your outboard. With Permatrims, you want no more than just the barest film of water running over the top of the foil when you are on plane. I don't know about other brands of foils, but I assume the same principle would apply. Like Jay and others, I often loaded for extensive trips and ran with a very heavy boat. I found not insignificant improvements in mileage and ride after I raised my outboards a notch above the original setting.
With Permatrims on twins, I found no need for trim tabs. With a single, I would consider using both.
One thing to check carefully is the mounting height of your outboard. With Permatrims, you want no more than just the barest film of water running over the top of the foil when you are on plane. I don't know about other brands of foils, but I assume the same principle would apply. Like Jay and others, I often loaded for extensive trips and ran with a very heavy boat. I found not insignificant improvements in mileage and ride after I raised my outboards a notch above the original setting.
When we re-powered we made one trip without the Permatrims. We reinstalled them immediately. It is not the same boat without them. I agree with those that say 8mph is too fast. We travel 6 or 16 when possible. Actually, it's more like 5.5 mph. The only time we travel in the range between is when we are getting pounded.
knewlin":14vm4v4i said:
For Slow cruising, I like the quiet no wake version so on my heavy 22 version, I am usually slightly under 5 knots water speed so there is no bow wave and very little stern wave. It might be 4 to 4.5 mph water speed or so. Generally, I am doing that using the tidal current flow so over the ground might be 6 knots or about 7 mph.
Harvey
SleepyC :moon
T.R. Bauer
New member
I agree that pretty much anything under 14-15 mph on a CD 22 is not really planing. And the 8-12 mph speed is more like an ugly inefficient wallow than a plane. But, you do get a nice view of birds, the sky, and airplanes.
I know I took a chance on the Davis Instruments model, but they really work well for not hardly any money. They are a one sized fits all approach though unlike the Permatrim. I can travel into 1-3 foot steep chop at 15-20 mph without much banging now and it is so much better than without them. I may have lost 1-2 mph at top speed, but the boat still goes 30 mph with a pretty heavy load with twin 45s, which I think is pretty good. It honestly feels like a different boat with them.
I know I took a chance on the Davis Instruments model, but they really work well for not hardly any money. They are a one sized fits all approach though unlike the Permatrim. I can travel into 1-3 foot steep chop at 15-20 mph without much banging now and it is so much better than without them. I may have lost 1-2 mph at top speed, but the boat still goes 30 mph with a pretty heavy load with twin 45s, which I think is pretty good. It honestly feels like a different boat with them.
With twin 40's and trim tab assist I have no trouble getting up on plane at 10mph, and then backing off the tab assist. Crossing Juan de Fuca in 4-5 ft beam seas, I run mostly ion the troughs at 10 to 12 mph. That is on plane and gives me the speed and angle to cross the waves (doing the jog and slog method) but still make time to get across. I would not want to be there in slow cruise mode below 8mph. Scary.
Harvey
SleepyC:moon
Harvey
SleepyC:moon
smckean (Tosca)
New member
Harvey, could you explain this method (or point me to a reference). I'm never quite sure how to handle such conditions.hardee":h7pxqffk said:
It is a way to run somewhat of a diagonal line across the direction the waves are coming. So the waves are coming across the port or starboard forequarters. Rather than maintaining that constant direction, it is not hard to run in the trough for a few boat lengths, or few hundred feet, then turn into the waves, cut the power to avoid slamming (from going airborne) over the crests, and then run in the trough again. Doing this, you want to be careful about what is coming at you from the side, and work and watch to stay out of the way of a breaking whitecap, and go over the wave that is less steep and be able to maintain direction toward your intended goal. For me, I prefer to be running into the waves (going up the hill) rather than running downhill and having to be watching over my shoulder.
Please note: I do not intentionally go into this type of water conditions. I regularly cross Juan de Fuca and often times get into Johnstone Strait. I have had to resort to this technique in both places, but very rarely. Mostly because I am very careful about weather conditions, directions, goals and timing.
Harvey
SleepyC :moon
Please note: I do not intentionally go into this type of water conditions. I regularly cross Juan de Fuca and often times get into Johnstone Strait. I have had to resort to this technique in both places, but very rarely. Mostly because I am very careful about weather conditions, directions, goals and timing.
Harvey
SleepyC :moon
smckean (Tosca)
New member
Thanks Harvey!
I understand your situation of having to cross rough water abeam.....that's precisely why I wanted to know your technique (a practiced hand). Of course, I too try to avoid such water, but it happens.....not as often to me as to you, but it happens none the less :wink:.
I understand your situation of having to cross rough water abeam.....that's precisely why I wanted to know your technique (a practiced hand). Of course, I too try to avoid such water, but it happens.....not as often to me as to you, but it happens none the less :wink:.