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View Full Version : Putting Trim Tabs on Sweet 16



65sweet16
05-26-2009, 12:55 PM
Hello i have a 1965 sweet 16 with a alpha one and 300 hp i raised the X dimension and have a clever on it it chine walks and becomes unstable at around 57 mph but has the power to go much faster. does anyone know how i could get the boat to become more stable thanks please reply.

Donziweasel
05-26-2009, 01:11 PM
Your thread title says it all. Trim tabs........

Just Say N20
05-26-2009, 01:17 PM
If there is too much play in the outdrive, side-to-side, perhaps hydraulic steering.

Have someone hold the steering wheel in place, and see how much movement you can induce by moving the outdrive side-to-side. This slop will be hard to overcome by steering one it starts oscillating, creating the situation you describe.

BigGrizzly
05-26-2009, 03:25 PM
Let me guess you have raised the X 1 to 2 inches and are using a Mirage plus. It starts about 55 and then at 57 you have to back out of it. My guess is you have a 23 pitch

zelatore
05-26-2009, 04:05 PM
Let me guess you have raised the X 1 to 2 inches and are using a Mirage plus. It starts about 55 and then at 57 you have to back out of it. My guess is you have a 23 pitch


I picture Griz holding a card up to his head a la Carson's Carnak while rattling off the above...

MOP
05-26-2009, 08:30 PM
Dump the cleaver and go to a 4 blade, Griz can get you where you need to go!

BigGrizzly
05-27-2009, 08:04 AM
Darn Zel you have seen me do this before:) Props make a difference , but it isn't always a cure all.

DonziBuoy
05-27-2009, 11:30 AM
I am curious to know if anyone has had experience with no trim tabs on the early 16s. I am buying one, and I noticed the boat has none, but the ending bottom, meeting the stern, has a definite hook in it. THis hook would seem to keep the boat's bow down. However, if you look at later classics and 16s, the hook is gone, leaving a straight edge.

WOuld like to hear others on this. - BTW, what brand of trim tabs is used by Donzi, and what is recommended on this board.

Just Say N20
05-27-2009, 11:35 AM
Trim tabs vs no trim tabs seems to be like Chevy vs. Ford.

Personal preference. I like them.

Donzi uses Bennett. They are a great company to work with.

http://www.bennetttrimtabs.com/

jl1962
05-27-2009, 12:23 PM
I am curious to know if anyone has had experience with no trim tabs on the early 16s. I am buying one, and I noticed the boat has none, but the ending bottom, meeting the stern, has a definite hook in it. THis hook would seem to keep the boat's bow down. However, if you look at later classics and 16s, the hook is gone, leaving a straight edge.

WOuld like to hear others on this. - BTW, what brand of trim tabs is used by Donzi, and what is recommended on this board.

My '67 Ski Sporter has tabs.....I NEVER use them and if my boat didn't already have them I would never put them on. My understanding of the hook is that it existed on the early boats to help them plane sooner - just like tabs. Remember - it was a ski boat. Do a search - lots of info here.

Where in NY are you? Post some pictures and try to get to the Dust-Off.

mattyboy
05-27-2009, 03:03 PM
the early boats came with boat levelor trim tabs , 9 X 12 tabs will do it, don't worry about the hook, I would get a good prop get some seat time use the boat and then think if you need them I very rarely used mine but in bigger water it was nice to know i could pull the nose down a tad.

if the drive has trim start there and see if you need them

DonziBuoy
05-27-2009, 03:21 PM
I am in Port Washington, LI, close to the city on LI SOund. The water here is choppy from the big yachts plowing through.

Thanks for the feedback on the hook and how effective it was. I wonder why Donzi got rid of that hook in the transom? Trim tabs were around in the 60's and early 70's. I have spoken with some owners of the later model years on trim tabs, including my own experience, the damn boat would just porpoise.

BTw, have another question about towing - I was wondering if my Subaru outback (2.5 engine, 165 HP AWD) can pull this boat?

jl1962
05-27-2009, 04:05 PM
Tabs WILL allow you to stay planed off at a lower speed and will curb some chine walk at higher speeds, but I don't think they are as critical on 16s as they are on 18s and 22s. Part of the reason is most 16s are 50+mph boats, most 18s are 60+mph boats and most 22s are 70+ mph boats. Come to Lake George next month and get a ride in all three and NO I don't think a Suburu will pull a 16.

JL

boxy
05-27-2009, 04:21 PM
Shea's 16 had an awesome set of tabs the year I saw it in the 1000 Islands.

BigGrizzly
05-27-2009, 06:21 PM
Our 1966 16 does not have then and BTW that hook is suppose to be there.

mattyboy
05-27-2009, 06:27 PM
I am in Port Washington, LI, close to the city on LI SOund. The water here is choppy from the big yachts plowing through.
Thanks for the feedback on the hook and how effective it was. I wonder why Donzi got rid of that hook in the transom? Trim tabs were around in the 60's and early 70's. I have spoken with some owners of the later model years on trim tabs, including my own experience, the damn boat would just porpoise.
BTw, have another question about towing - I was wondering if my Subaru outback (2.5 engine, 165 HP AWD) can pull this boat?



donzi didn't get rid of the hook in the 16, and older boat might have a more pronounced hook from it's long life on a trailer or on a lift with bunks. the only problem with the hook is if it is not close to be uniform on both sides.

porpoise is strictly caused by the prop, and depending on the prop the speed and duration of the porpoise will vary, I had my 67 16 dialed in so the porpoise would only happen betwwen 23-25 mph so guess what I went 20 or 30 mph no problem. with other props it would be from 25-30 mph some even higher

the subaru will be hard pressed to pull the 16 fully loaded even with a light alum trailer my rig fully loaded on a steel custom tandem trailer went just about 3500 lbs and I made several long distance hauls with a 3.8ltr v6 around 220 hp windstar you need something rated for at least 3500 lbs

BigGrizzly
05-27-2009, 06:31 PM
We have removed the hook on a friends and it was a disaster. It is now back on lucky we copied it before removing it.

mattyboy
05-27-2009, 06:37 PM
We have removed the hook on a friends and it was a disaster. It is now back on lucky we copied it before removing it.



I was gonna say that , and if there is a hook between the keel and the inner strakes that would be a problem, but if it is uniform on both sides and where Donzi intended it to be out by the chine forget about it

MOP
05-28-2009, 09:35 AM
Tabs on a 16 & even 18 will always be a debate, I loved being able to settle the boat down and adjust the balance with added passengers. Does a 16 need tabs for most running probably not I never ran without, but for added handling and comfort in some situations yes.

BigGrizzly
05-28-2009, 09:45 AM
There is no debate Tabs may not be necessary but don't hurt if installed correctly. You don't have to use them but are nice to have if you do need/ want to use them kind like power trim.

BERTRAM BOY
05-28-2009, 10:10 AM
I have a similar setup, and don't have or need tabs. I would try a Mazco 3 blade round ear or something as close to a Volvo Ultra as you can find.

Is your 16 port helm and are you using a left hand or right hand drive?

Also, where in Connecticut are you? I'm in CT as well.

Sweet Cheekz
05-28-2009, 12:19 PM
Nice to use the tabs to level the boat in any quartering seas and bring the bow down in a bigger head sea. Used them like crazy this past weekend to keep the boat level and dry. SC