Boat yard said trim tab never worked in 17 years - Maxum Boat Owners Club

sandiegoguy · 10-31-2016, 11:15 PM

My boat is getting bottom paint and figured it was a good time for them to check the trim tabs. I noticed when I used them the boat would lean so I knew one wasn't working right. btw, it would lean to the port side but I didn't tell the boat yard this.

So they came back and said the port side switch was mis-wired and probably like that since the factory! How in the world does this happen and none of the previous owners noticed the boat leaned....The boat has 530 hours and nobody noticed this until I come along and noticed it in the first hour. Not even the surveyor noticed!

Really weird.

mmwjr · 11-01-2016, 01:03 AM

Some folks never use them and others just don't realize the boats attitude verses trim.

TJK · 11-01-2016, 04:26 AM

Quote:

Originally Posted by sandiegoguy

My boat is getting bottom paint and figured it was a good time for them to check the trim tabs. I noticed when I used them the boat would lean so I knew one wasn't working right. btw, it would lean to the port side but I didn't tell the boat yard this.

So they came back and said the port side switch was mis-wired and probably like that since the factory! How in the world does this happen and none of the previous owners noticed the boat leaned....The boat has 530 hours and nobody noticed this until I come along and noticed it in the first hour. Not even the surveyor noticed!

Really weird.

Wow! But I noticed when I did a sea trial on 4600 SCB with the Cummins 370B engines, the boat didn't need much trim tabs. So, I can see that it hasn't been caught until now....

BTW, the port side trim tab switch control the starboard side trim tab. If the boat "lean to the port side" as you described, the starboard side trip tab (controlled by the port side switch) is working.

sandiegoguy · 11-01-2016, 04:47 AM

TJK

On my boat, as soon as I plane, I can tell it needs trimmed. Maybe I'm just more particular in that area but it bugs me having the bow pointing up instead of level.

I'm not sure what you meant with your second statement. Basically I could tell the port side trim wasn't working because when I used it the boat had no reaction. But using the starboard (right side) switch the boat would react. To me it seemed the left switch was for port, right switch for starboard and left switch did nothing. I could be mistaken since I was trying both of them at the same time 95% of the time I tested. Regardless, I'm picking the boat up Tuesday and can test it going back to my slip.

TJK · 11-01-2016, 05:16 AM

Quote:

Originally Posted by sandiegoguy

TJK

On my boat, as soon as I plane, I can tell it needs trimmed. Maybe I'm just more particular in that area but it bugs me having the bow pointing up instead of level.

I'm not sure what you meant with your second statement. Basically I could tell the port side trim wasn't working because when I used it the boat had no reaction. But using the starboard (right side) switch the boat would react. To me it seemed the left switch was for port, right switch for starboard and left switch did nothing. I could be mistaken since I was trying both of them at the same time 95% of the time I tested. Regardless, I'm picking the boat up Tuesday and can test it going back to my slip.

Pressing the port side trim switch to bow down will cause the starboard trim tab to deflect down; therefore, increasing the starboard stern lift and the boat will lean to port. If the boat leans to port, your starboard tab is working.

BTW. for the running trim/angle, the fresh water tank which carries 100 gallons/836 lbs is located below the water line and well forward of the boat's longitudinal center of gravity. Keeping your fresh water tank full will balance your boat better.

sandiegoguy · 11-01-2016, 05:53 AM

ok that's what was happening. I'd press both trim tabs and the boat would lean to port. My water tank is about half full. Another 400 lbs or so may help some but I could tell the trim tabs will make a huge difference unless I put about 2000 lbs in the bow. I had a smaller boat with them which I used all of the time. Like I said, maybe I'm more particular about it.

Here's an example of what I try to avoid (top pic) compared to what I want. Maybe that top pic angle doesn't bother some but drives me nuts.

shrew · 11-01-2016, 01:51 PM

There are two things in the statement relayed from the boatyard:

1) Trim tab switches are mis-wired.

-> I would be curious what he means by this. Are both switches not actuating the cylinders? Only one not actuating? (If so which one?). Are they working but backwards? (Note, the Left-hand switch actuates the Starboard tab. right-hand switch actuates the Port tab. On Bennet and many others, UP on the rocker switch moves the tab Down)

2) It was probably that way from the factory.

-> This is pure speculation. He doesn't know if these were factory installed or professionally installed aftermarket. He has no idea if service has been done on them. I'd treat this as anecdotal unless there is more information which we aren't aware of.

The cylinders themselves are both serviceable and replaceable. They are relatively inexpensive so he cost difference isn't huge, so straight replacement isn't unreasonable. The seals wear out over time.

I would replace if they are leaking oil when you use them in the water. Puking water when you use them on land or simply not working at all.

sandiegoguy · 11-01-2016, 10:48 PM

Yeah, it is pure speculation that the factory screwed up and I kind of doubt that. There has to be some testing before releasing the boat but who really knows. But the boat has 500 hours on it and if the previous owner just piddled around then it's possible they never even tried them.

Just one trim tab was not working and I'm not sure which one. All i know the boat would lean to port when I activated both of them (put tabs down). That's how I knew one actually worked.

I picked the boat up today, tested it all out at ~2500 rpms and trim tabs now both work and boat levels out nicely. They didn't have to replace anything (other than zincs) and it was just that wire issue and about $300.

Next time I'm at the boat I'm going to take my gopro and check the movement of the trimtabs while in the slip.

speedysprocket · 11-02-2016, 01:27 AM

Easier than that- just watch the fluid level in the reservoir. Should go down when you put the tabs down...0

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sandiegoguy · 11-02-2016, 02:48 AM

Quote:

Originally Posted by speedysprocket

Easier than that- just watch the fluid level in the reservoir. Should go down when you put the tabs down...0

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Good idea, even easier!

Phillbo · 11-02-2016, 03:56 AM

How the boat reacts is a much better indicator of how the tabs are working.

Foxy 01 · 11-04-2016, 07:42 AM

Well the factory certainly screwed up a few years back the cooling systems being installed backwards resulting in many saltwater ingested engines. I had to have two rebuilt. Strangely it took a while for the mechanics to realize the problem and after several incidents. Oh dear..A few red faces and lots of silence.

sandiegoguy · 11-04-2016, 04:06 PM

Quote:

Originally Posted by Foxy 01

Well the factory certainly screwed up a few years back the cooling systems being installed backwards resulting in many saltwater ingested engines. I had to have two rebuilt. Strangely it took a while for the mechanics to realize the problem and after several incidents. Oh dear..A few red faces and lots of silence.

Are you referring to the diesel versions and the exhaust riser location?

TJK · 11-04-2016, 10:18 PM

Quote:

Originally Posted by sandiegoguy

ok that's what was happening. I'd press both trim tabs and the boat would lean to port. My water tank is about half full. Another 400 lbs or so may help some but I could tell the trim tabs will make a huge difference unless I put about 2000 lbs in the bow. I had a smaller boat with them which I used all of the time. Like I said, maybe I'm more particular about it.

Here's an example of what I try to avoid (top pic) compared to what I want. Maybe that top pic angle doesn't bother some but drives me nuts.

In the top picture, the boat is running probably close to WOT over 24-25 knots with trim tabs all the way up. It might have had a lot of fuel but empty fresh water/holding tanks. It is running at a slightly higher angle (my guess is around 6 to 7 degrees). However, when cruising in following seas, that is what is necessary. Boats can go out of control in following seas. The big bridge boats have high VCG and less maneuverability. The naval architect at Maxum who designed the 46 and 41 most likely wanted to have this natural characteristic to keep the bow slightly high with no trim tab input. As designed, 4600SCB ended up to have a very straight forward and forgiving handling characteristic in rough seas and no dangerous bow steering/bad habits at all.

The boat in the bottom picture is running at slightly above displacement speed, perhaps around 12 to 14 knots since the hull is not lifted yet and running angle is very flat.

sandiegoguy · 11-04-2016, 10:48 PM

Yeah I just grabbed 2 pictures to give a visual as an example, it may be a little extreme. I can tell when I'm running 2300rpms or so my boat is bow up (too far up) and it's annoying to me. I'm not in rough seas. I've had other boats with trim tabs and they help quite a bit. I'd have too much weight on one side (smaller boat full of people) and I can make up it for it with trim tabs along with just leveling the boat when flying across a lake. To me it's a must have but to others maybe it doesn't matter.

The previous owner only used up 30 hours in 3 years so obviously he didn't care and probably never touched the switches.

As soon as I got my boat back from the yard I did a test and the boat handled just like I expected so I was happy. No lean and boat leveled out some once i planed.

TJK · 11-05-2016, 01:07 AM

Quote:

Originally Posted by sandiegoguy

so my boat is bow up (too far up) and it's annoying to me.

How far is “too far up”? Let’s talk about the running angle in general and optimum trim for 4600 SCB. I am VERY picky about the trim angle and performance/fuel consumption. I even installed the inclinometer and Bennet trim tab position indicator so that I can accurately assess and fine tune my boat’s running angle. 4600 SCB with my Cummins 450Cs likes to have about 50% trim tab down at cruise (2100 RPM) to achieve what appears to be the most optimum running angle of 4.5 degrees (see the pic). With that, my boat (with clean bottom and clean props) cruises very efficiently at nearly 20 knots, burning 13.4 gallons/hr each. If I am going into head seas, I can bring the bow further down with trim tabs to make the ride smoother, but the boat will slow down slightly. If I am going down in following seas I can bring the bow up by retracting the tabs, but again the boat will slow down slightly. In any case, I have full control on running angle with my tabs.

Remember the trim tabs can only bring the bow down, and no device can bring your bow up. You will appreciate the bow’s buoyancy when you are racing down on the 7' roller following seas with your SOG reading going back and forth fast between 15 to 25 knots! The forefoot section is out of water and she is using her keel (remember we have a small, but effective keel?) to maintain its directional stability.

BTW, I have about an hour of sea trial time with 370B engines boat. She was trimmed slightly differently but nicely (less than 5 degrees) at 16 knots with some minor trim tab input. I believe its due to much lighter engine weight (370B is much lighter than 450C) and slower cruise speed.

sandiegoguy · 11-05-2016, 01:21 AM

What is too far up, hmm, I couldn't say. Just what feels right to me. Sounds like you have your boat really dialed in and I'm pretty far from knowing the different burn rates, optimum angle, etc. I am a total rookie with this type of boat. I've been boating for 20+ years but nothing this size so I'm always learning but I do know what I like and dislike so I just go off my gut/preference for some things.

I'm very interested in the inclinometer and trim tab indicator. Can you post more information about that? what is needed, install, etc. This would really help me dial in optimum settings like you have with your boat. I found it odd the boat doesn't have trim tab indicators and they got really cheap not putting a holding tank level gauge in.

One thing I may actually do is hire a captain for a day out at sea just to gain some expert knowledge with my own boat. I read the other day that it's not advisable to turn the engines off at sea....ever! like while fishing. Unless you are anchored and in a place where you don't mind being anchored if something goes wrong. A few posts mentioned they'd leave at least 1 engine running at all times. I realize others may think this is nuts also. I went fishing with a friend on his Hatteras and while out all day he never turned the engines off which I thought was odd at the time.

But I'm about 90% done getting my boat mechanically sound where I feel comfortable so until then I only go maybe 2-3 miles off the coast. (need to replace an exhaust riser , check heat exchangers & aftercoolers) Then at that point I can venture out more and eventually make some Mexico trips which is just miles away.

sandiegoguy · 11-05-2016, 01:27 AM

I found one inclinometer with a +/- 10 degree indicator. Does it really need more than that? I noticed the one you have costs about $65 at west marine but it goes to 60 degrees with a smaller 5 degree indicator.

rxmaxum · 11-05-2016, 04:13 PM

Sandiegoguy, You might try an RV place. They have less expensive inclinometers. typically <$20.

Or, just to get an idea if you really need one, or how you are performing using the gut-feel approach, there are apps for many smart phones that can do a very good job for both pitch and roll. I wouldn't want to use the smart phone all the time though.

TJK · 11-05-2016, 10:42 PM

Quote:

Originally Posted by sandiegoguy

I found one inclinometer with a +/- 10 degree indicator. Does it really need more than that? I noticed the one you have costs about $65 at west marine but it goes to 60 degrees with a smaller 5 degree indicator.

All you need is +/- 10 degrees. Mine is Reiker, and I only use the larger top scale +/- 6 degrees side.

I don't have a good picture of the the Bennett indicator, but it is model TPI2000. I love it. The installation wasn't too bad, except fishing the wires from the trim cylinders to the bridge instrument panel was a lot of work.

Tab Position Indicator (HYDRAULIC SYSTEMS ONLY) - Bennett Marine