Permatrim Hydrofoils

[Jon - CLou]

Quote...Did you notice any straight line steering differences?

The boat pulled to the right only when I backed off the throttle quickly. I did leave my two portside weights at home (Cynthia and the 90lb kicker), so, leaning to the starboard side could of caused that.

[katkt]

Mike,

Yes, I went with the factory recommendation and installed
the twin 90 Hondas. I don't know why there would be a
problem with them on twins as per Charlie above. The forum
I was following before I bought mine, had alot of guys with
twins, and alot of them gage a boat by how long it takes to
break it, and if it will run 50.
One of the interesting side lines I was following had to do
with raising the motors a hole or two, to reduce drag. This is
apparently made possible because, the foil holds the water
over the prop better. Just throwing that out for thought.
Its my opinion but I would think that if the foil flexes you
probably aren't getting its real worth. They have been selling
them for awhile, if motors are being torn up I can't think of
anyone who would be bashful about getting the news out.

Gordon

[C-WEED]

How about one tested on a dingy?

[Mighty Bite]

Already tested it on me.

[katkt]

I hope I'm not violating a rule here, but if you do a search for
The Hull Truth, scroll down to the vendors forums you'll
find a QandA with feed back under Permatrims, I had already
ordered some of the plastic whale tail thingies when I found
these.
This is as close to an endorsement as you'll get out of
me until I have a chance to install them and try them out.

Gordon

3rd Byte, I had to read that 3 times before it clicked,
I'm slow

[SeaSpray]

After installing my Permatrim a few weeks ago I finally got to give it a real try. (Last time out the water intake got clogged with sea grass and I lost one of the plastic intake screens - but that's another story.)

Although conditions were not the best for assessing any changes I could not tell that much difference. I did notice that at higher speeds if I trimmed up the boat would start to porpoise. I don;t think it did that with the smaller foil. Hs anyone else noticed this?

I did do some hard turns and it does seem that the stern will not slide or wash out with the permatrim.

Steve

[Sea Wolf]

Steve- I think the increased tendency to porpoise comes from the greater EFFECTIVE range of trim available with the hydrofoil. Although the angular range is the same, the foil increases the effect of the trim angle through the action of the foil plate. Thus you can trim the bow up enough to make it so light as to be unstable. (The plate gives you more at the other end of the trim range, too, to force down the bow.)

The lesser ability to slide or wash out the prop and lower end comes from the insulating effect of the plate above the prop and, in the case of the Permatrim, the turned down edges of the sides of the plate.

JMHO and not at all costing you $0.02 even!!! Joe.

[Da Nag]

[SeaSpray]

Bill - I do have the trim tabs. I have not really looked at the motor angle while on the trailer. I am wondering if you can tell when the thrust is parallel to the bottom when on the trailer? I don't think I could tell while motoring - by feel.

It seemed that my trim gage was just above the midpoint when it started the porpoising. I also wonder if the range of trim has been off set so that I will now need to run with trim set below gage midpoint for normal conditions.

Steve

[TyBoo]

[SeaSpray]

Thanks Mike,

I will try that method next time I am out. It does make sense for the motor to be parallel with the water surface.

Steve

[Big Mac]

Might as well throw in my two cents worth. The Mary Ellen has twin 40 HP Hondas. The only complaint I had was the ability to get lateral trim without going to trim tabs. I ordered a set of Honda SST hydrofoils and did not like the way they mounted(didn't even drill any holes, just held them up and did not like the looks). I had just about given up when I stumbled on to the Permatrims. I have now had them going on the second season and really like the way the boat handles. Just a touch on the trim button and the side to side trim is corrected. I am concerned with the following sea potencial handling problem but have never encountered any problem yet. I wonder if the fact that the Permatrim is deeper in the water would help to minimize the effect? As far as quality and how they look I could not be happier. It also seems to handle better at slow speeds around the dock, it's more responsive.

[Falco]

The US rep for Permatrims (shipyardisland.com) had no info about Permatrims and broaching in following seas, but here's what the manufacturer of Permatrims (in NZ) says about broaching in following seas:

Permatrims work differently to trim tabs and should not make a boat more susceptible to broaching in a following sea, they will help to stop your boat from broaching by giving your more trim control so you can hold your bow up, this is one area were permatrims differ from trim tabs, trim tabs cannot lift your bow only lower it.

I hope that helps explain the difference. If you need any more info please email me and I will try to help out.

Thanks for your enquiry.

Regards
Colin Chapman

I did some research on the Net, but couldn't find anything directly linking trim tabs (or accoutrements like Permatrims) to broaching in following seas, but numerous references (Bennett and Lenco owner's manuals) state that trim tabs should be kept up (retracted) in following seas "to improve handling" and/or to prevent the bow from "digging in" (to the next wave). My personal experience is that extended trim tabs in large following seas (6-10 feet) WILL cause a boat to broach -- and it happens very violently and rapidly, without warning and is uncontrollable. Colin's point above makes sense. If kept trimmed down in a following sea, a Permatrim equipped outboard should function to really keep the bow up - important to prevent digging in to the next wave...