Trim tab Question

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frosh coach

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I have a 94 Sea Ray 300 Sundancer with twin 350/260 Merc FWC Alpha Gen II drives.

Last yr was my first with this boat. I curren'ty have 12x12 bennett tabs on her which I don't think are large enough. Checking the Bennett website it said they should be 24x12.

Does anyone else havethe set up on their boat?
 
12x12 should be more than enough to trim that boat. If you are able to trim the bow down while up on plane then they are doing there job.
 
The boat squats at anything below 3400 rpm. I figured the larger tabs would help with that.
 
Tabman should be along shortly. He will know what you need.
 
If your squatting under 3400, see if the bottom is clean. That will make a huge difference. Check load distribution. How much stuff do you have on board? Check your props for damage. You should come on plane under 3000 and stay on plane down to around 2200-2400. I always trimmed mine down to get up on plane then once on plane i trimmed them all the way up unless I needed to trim a little port or stbd. '87 sda340.
 
Out on our test track we recorded a top speed of 44.1 mph turning 5000 rpm and recording a sound level of only 93 decibels. Our best cruising speed was calculated at 34.6 mph turning 4000 rpm burning 11.3 gallons per hour per engine. The 300 also clocked an impressive time to plane test of 4.9 seconds and a 0-30 run of 8.4 seconds.
I hope you can use this related information to better utilize your boat. Sorry I do not have the tab size for this test.
 
Adding to the above, are you using the outdrives to trim the boat? Are you reaching WOT with your current prop setup?
 
Thanks for all the replies.....
Iron Works - What year 300 did you test?

Kida - Yes I use the drives. I'll double check the WOT. If I recall I was at 4200 or so.

I should add that I purchased the boat last summer in July. The previous owner used her sparingly. The boat was painted, 2 yrs before and chipping in spots. This season I’m gonna try to remove as much paint as possible. There isn’t a great deal of build up so that should help.

I’m also having my mechanic do a soup to nuts tune up including the timing and rebuilding the carbs. Hopefully this helps.
My top end was only about 25 mph.
 
Bennett uses as a guide 1inch per foot, so your tabs should be 30x12. You really can not over trimtab the boat but surely can be to small.
Give bennett a call, they are very helpful and will work with you.

Cor
 
quote:
Originally posted by van lafermine

12x12 should be more than enough to trim that boat. If you are able to trim the bow down while up on plane then they are doing there job.

Click to expand...


Frosh Coach,

Yup, they are too small. Larger Trim Tabs will make a great difference. If you visit the SeaRay Owners Club forums you will see that we have helped a lot of Sundancer owners fit larger Trim Tabs with great results.

If you could post a picture of your transom I would be delighted to see what options you have.

By the way, I see you are in New Haven, I grew up on the Thimble Islands!

Tom McGow
Bennett Marine
 
Tim
Thanks for your reply. I'm going to work on the boat tomorrow do I'll take a piic and post it.
I love the thimbles.... I keep the boat in new haven. Kelsey's cove is another summer hang out.

Chris
 
Thanks Chris,

OK, in order to see what the largest Trim Tabs we can fit I need to know two measurements;

1. From the centerline of the outdrive to the chine flat.
2. From the centerline og the transom to the centerline of the outdrive.

bt1.jpg


Tom
Bennett Marine
 
Tom:
1. From the centerline of the outdrive to the chine flat is just about 31".
2. From the centerline of the transom to the centerline of the outdrive is almost 17".

Chris
 
Thanks!

Sometimes it is possible to put another pair of Trim Tabs between the keel and the outdrives. We do that quite a bit on larger SeaRays with great results. But in your case there is not enough room.

But there appears to be plenty of room outboard of the drives to fit larger Trim Tabs. It also Do you think that you could fit a 24" x 12" Trim Tab and still be 8" from the centerline of the outdrive?

I would also suggest that it have our 3" dropfins. These dropfins capture water pressure that is lost out the sides and channels it aft to gernerate extra lift.

MP80820587.jpg


If a 24" Trim Tab will not fit, you could go with an 18 x 12 with dropfins.

You will have to move the actuator on the transom.

The work will be worth the results.

Tom
Bennett Marine

Trim Tabs should be a minimum of 8" from the outdive's centerline to prevent disturbing the water flow to the propellers.
 
Tom:
I'm going to add the larger tabs. Thank you for all the advice.
Chris
 
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