Trim tabs on 17 footer....

[ucjohn]

www.updplastics.com makes 3/8" thick custom and stock windshields.

[Miguel]

Check my new post on the subject of windshields........

[Miguel]

Sorry for the double post, but this one should actually go here (instead of on the windshield thread):

I just posted 3 new pics in my gallery. On the first one you can see the new winscreen. It made a HUGE difference compared to the old one. It rained on the morning and I could actually see through it, as opposed to the old one.
The whole purpose of sunday´s trip was to test the new trim tabs. The installation is almost finished, save for a few finishing touches. In a nutshell: They are the best product I have ever bought for the boat and make a world of difference. I feel like the boat just grew 3 more feet. On the day of the test the lake was pretty windy and I would say we had a steady 2-3 feet chop on the afternoon. I tested both with the tabs raised and then lowered when running head on against the seas. Even when the ride may get a little wetter, there was no bouncing and most important, no hitting whatsoever when the tabs were used. By being able to move the point where the boat make contact with incoming waves to closer to the bow, where there is a deeper deadrise, the ride became completelly enjoyable. I highly recommend them to any 170 owner who gets into nasty seas once in a while.
A couple of details shown on the pics are the notch I had to cut in the swim platform to accomodate the port cylinder and the location where I chose to mount the pump. It was mounted as high as possible inside the console, as I wanted to keep the storage space underneath. I know taht the wiring still needs more work, but hey, I´m not finished yet!!!!!

[JimCt]

Nice installation!  Pump location will protect it from salt spray which can/will do a number on anything electrical.  I was thinking the notch in the platform would have to be bigger for the tabs but what you've got there is hardly noticeable.

With the bigger engines used nowadays tabs or at the least foils are a necessity to trim the hull properly.  Did you see much difference in the RPM vs. speed ratio?  I imagine the boat will also stay on plane at lower speed.

[Miguel]

Jim:
I didn´t do a test to see how low I could go on RPM´s without losing planing ability. I will do it as soon as I have a longer day in the water......
Willpost numbers when I get a chance, but I believe i have gained some speed at different RPMs as compared to no tabs.
Another advantage is that the tabs tend to eliminate the stern down attitude of this boat, even when raised, because they act as a foil of sorts.  You see them touch the water when getting up on plane and also when two heavy guys are at the stern.

[JimCt]

Sort of like having load-leveling shocks in the back of your car.

[jy118lfd]

Great thread it really goes from start to finish. I just installed tabs on my 19-6 but have yet to get it in the ocean for a real test.
I used the lencos though mostly cause I got a great deal on them. So far they work great.

[Miguel]

The thread is not over..... I still have to go out for an ocean test too.  I´ll also try and post some numbers.  
My first experience out on the lake was highly positive.  Gatun lake in the Panama Canal can get very nasty, just like the sea.  That was the case on sunday.  I did not slam the hull once when running head on against the seas.

[Miguel]

Another thing on my to-do list was to fix the bilge pump wiring and add a backup pump.  I added a new pump for a combined nominal pumping capacity of 2300gph (1500+800).  I wonder what the real number is.
Anyway, I tought about splicing the discharge hose of the new pump to the existing hose by means of a vertically oriented Y.  I ended up deciding against it and added a new thru hull.  I cannot tell you how difficult it was to rig both thru hulls through the little round deck plate on the side of the boat.  You really need to have tiny hands or be very clever..... :)
I went shopping for the new thru hull and found these nice nylon ones with stainless steel face, like a cladding.  I think they look very good, what do you think?  One is  3/4 inch and the other one is 1-1/8 inch diameter.
This is the before pic:

 


You can see the trim tabs on the box in the floor, before installation.
And this is the after pic:



Sorry about the ugly cover on this one, but it was early in the morning as I was leaving for work and had no time to take it off.

[JimCt]

Discharges and the tabs look good!  With the two discharges there is no danger of one pump back-feeding into the other.  Also, if by some misfortune both pumps need to run, the two exit points allow for less back pressure.  Metal looks better than the plastic by a long shot.