mix'n match trim tabs?

[vas]

designing the helm layout and came across the trim tabs rather ugly controller.
now, I have trim master tabs running fine, but with no indicators.
Thinking about getting Bennett trim tab indicators (140USD), getting a set of Bennett actuators and keeping the pump electronics and controllers as is.

Total conversion cost 350 euro (estimated with all the shipping charges and hopefully no import tax!)
Second option is get a full set of actuators, electronics and pump for a lot more (I think!)

Not particularly happy with either option and may scrap the project and keep the existing tabs.

Qs:
Doesn't seem to have LARGE and SMALL actuators (most look similarly sized) no matter you want to push a 15ft or a 50ft boat. My tabs are around a metre long by 20cm (or 40X9 inch) which are almost OK (according to the rules) for a 43ft planning craft.
So, do I buy ANY of them Bennett actuators? Website is not particularly helpful, seems you have the option of the normal, the short and the ext pipe ones.

Will my pump and electrics do the job, tbh I cannot think of a reason not to, but just to be safe.

Can I run them in tandem (as in keep the trim master cylinder and add the Bennett next to it)? I understand that this is tricky as volumes and piston sizes may be different so one gets to do more work than the other, but I guess they'll cope better on harder stuff.

Any other option to have indication (using NMEA2K so that I don't have to have two different displays up and down) on existing tabs? (couldn't find any!)

cheers

V.

 

[jfm]

Hi vas. A few thoughts:

1. Those are big tabs. Bennett would need 2 rams per tab I bet

2. No reason why existing pump won't run Bennett rams. Bennett specify the red oil as in auto power steering

3. You could have a Bennett ram and an existing ram on same tab so long as you join the piping in parallel

4. You could consider having no indication. I've managed fine with no indication on previous boats

5. If you get the Bennett rams with the indicator unit inside I think it just drives the Bennett led indicators. to get n2k you need additional black box to convert Bennett analogue to n2k. I have the very nice maretron blCk box on my current boat for this

6. Life is maybe too short but you could take a throttle cable from the tab, 1m long, to potentiometer inside the transom and convert analogue voltage to n2k via a maretron box. But not ideal. Race boats with single helms sometimes use the throttle cable method driving a mechanical gauge on the dash

 

[vas]

Hi vas. A few thoughts:

1. Those are big tabs. Bennett would need 2 rams per tab I bet

that were my thoughts John.

2. No reason why existing pump won't run Bennett rams. Bennett specify the red oil as in auto power steering

yep, that's what I use on mine

3. You could have a Bennett ram and an existing ram on same tab so long as you join the piping in parallel

need a T and a bit more pipe and some olives. Main issue is that I already have the holes for my rams, so new one is got to be placed nearby. Ideally would like to block these holes and space the two rams properly.
Ah, need to get rams that are same size (retracted and extended, that will be interesting!)

4. You could consider having no indication. I've managed fine with no indication on previous boats

5. If you get the Bennett rams with the indicator unit inside I think it just drives the Bennett led indicators. to get n2k you need additional black box to convert Bennett analogue to n2k. I have the very nice maretron blCk box on my current boat for this

6. Life is maybe too short but you could take a throttle cable from the tab, 1m long, to potentiometer inside the transom and convert analogue voltage to n2k via a maretron box. But not ideal. Race boats with single helms sometimes use the throttle cable method driving a mechanical gauge on the dash

John, the reason I started this thread is the 130USD kit for two Bennett trim tabs top mounts with the cabling, sensors and rods AND the black box that does the analogue to NMEA2K conversion! check ebay # 301212215272

Going Maretron (although we agree that it's the best thing available!) is going to set me back at least a couple of Ks and I'm not keen on that atm.
NoLand will take care of the engine data and a few NMEA tank sensors black and diesel tanks. That's enough for me.

cheers

V.

 

[vas]

hm,

I may have to reconsider!

found this on the web, this guy is testing various NMEA bits of kit and seems to produce interesting and revealing reports:
http://www.panbo.com/forum/2013/04/...-kit-does-not-work-with-garmin-nmea-2000.html

cheers

V.

 

[jfm]

Hmm that doesn't look good. I wasn't aware of the garmin incompatibility. That panbo forum is usually pretty reliable

I actually have the gbt10 garmin box, not a Maretron box. Your links above reminded me. Sorry for my duff reference to maretron above - it's hard to keep track of all the gadgets one collects these days sorry. The gbt10 functions very nicely by making a pop up display on garmin screens of tab position, whenever you move the tabs. You can also select a permanent display if you want. But yes it looks like you'll have to buy gbt10 in addition to other hardware, eek. Or go with my option 4 at least this season

 

[MapisM]

V, are you sure that your boat needs the trim tabs, in the first place?
I mean, I've been on several "old school" hulls of similar type and size as yours, and I can't remember any where tabs were really necessary (as opposed to smaller and/or much faster boats, where they are essential).
Setting them neutral and forget them was the easiest way to deal with them, in most cases.

In other words, you could fix the tabs in neutral position, by mean of a couple of steel bars on each tab, and see how the boat goes.
My bet is that the hull will cruise nicely anyway.

There's one thing which you could miss though, and it's the possibility to correct the boat listing in crosswind.
But depending on how much the boat is sensible to that, you might decide afterward if it's worth bothering with a proper installation (with cylinders, pumps, controls, etc.) or not.

Just a thought, anyway.

 

[Nick_H]

When I bought the current boat I pointed out to the broker (Princess Yacht Sales) that there was no trim tab indicator. They told me Princess didn't fit them because they were too unreliable. I don't know if this was the real reason, but I've had other boats with them and they have all stopped working sooner or later, so on that basis I'd say they have a point. This was a 2004 boat, and modern ones may be better of course. I find indicators useful on small boats, because they tend to react more noticeably to small changes in trim, but on the P57 I can't say I've missed them.

 

[jimmy_the_builder]

the reason I started this thread is the 130USD kit for two Bennett trim tabs top mounts with the cabling, sensors and rods AND the black box that does the analogue to NMEA2K conversion! check ebay # 301212215272

That's a good spot, thanks - I've just ordered one (admittedly from West Marine, rather than ebay) to use with the Raymarine i70 I've got coming.

 

[vas]

ΟΚ,

John, I'll go for option 4 keep the thing as is.

MM, I do have trim tabs fitted with pump and rams (not leaking fully operational) and I already "invested" the amazing sum of 12euro or thereabouts to get new seals for them, so they are brand new looking, just need a lick of antifoul or two, I also doubt they are going to be of great use, but if the price was right...

Nick, thanks for the info, I'd have thought that such simple sensors would work for longer!

Jimmy, glad to be of some help, it's usually you helping me out

So probably invest said amount on a decent air horn, but seems that I'll need more than 300euro for the bleeding pump alone which is not appealing...
watch out for my next thread

cheers

V.

 

[GrahamHR]

You could use the Bennett indicating cylinders but not connect up their hydraulics to a pump; that way, they would just be driven up and down by the trim tabs themselves . Their internal spring that forces the piston back in to the cylinder in the event of hydraulic fluid pressure loss could also be removed. It might need a non pressurized reservoir attaching to the hydraulics though, to provide fluid for lubrication of the O rings. Bennett themselves have a kit to connect to NMEA devices, cheaper I think than the one with their dedicated indicator.

 

[vas]

Interesting idea, although tbh once I'm that route, it's a few euro short of connecting them in parallel to the other rams

so, new Bennett actuator cylinders (aka rams) circa 200USD shipped
sensor top mounts with cables 2X35USD

OR 2X55USD + shipping for 2 port ones ready assembled with red wires, OK, I can live with that as there's no intelligence in the sensor and all the work is done by Garmin's black box to which I connect the cables as I wish...

Garmin GBT-10 195USD (shipped)

so around 340usd or 300euro for the lot. Can anyone better that?

Or almost 300GBP for a decent 24V 120+psi air compressor and then some more for a single Kalhenberg chrome plated horn.

What does the panel think?
JFM's not allowed to answer that as I'm sure I know his answer!

Actually all started by bumping onto this on ebay. ebay # 221483316177, (must be something wrong regarding the length in the ad, as it should be around 1m - 37inches)
Really keen to have black horns on the brilliant white coachroof
Not sure what's that black finish is and how long it will last though...

Which brings up another interesting cheaper option/solution where I get my dual el. horns painted matte dark grey as the other bits in MiToS. I may have to ask Alekos on that and how long they'll last.

V.