Trimming

[adrianm]

Does anyone have any tips to pass onto a novice regarding trim tab and sterndrive settings?

I am never quite sure that I have everything in the proper place!

 

[Guest]

The tip is to experiment! Before "playing" with your trim tabs, trim the leg up first. You will know when the leg is up to far by the change in the engine noise. Also, as you trim the leg up watch the change in the wake, this will give you good idea of how the trimming is operating. How the boat is loaded will also play a role, number of people, how much water (if any) and where the tank is placed will effect trim, also how much fuel you have onboard. Sea state will also play a role. Once you have the leg trimmed then you can adjust your trim tabs accordingly. There are no rules, it has to be done by feel but also understand what happens with the trim tabs. Lookw hat happens when you put them in the bow down position and then when in the bow up state. Do this when your not moving so you can see exactly where the tabs are in each state. You should find it easier to get on the plane by having the tabs in the bow down position so you get extra lift on the stern. As you get on the palne and trim up the leg so you can bring the tabs up. All I can say is experiment and "feel".

 

[hlb]

Trim tabs are for different sea conditions. Bow down is better
for going into the sea and bow up for when the sea is behind
you. You can also trim the boat to lean into the sea when its abeam.
They also make the boat faster, so get the boat on the plane
then adjust trim down a little and wait to see if speed changes,
then try more trim and wait.
If in any doubt in rough sea keep the trim up, its safest

 

[Guest]

David is quite right. We have the same boats and it is a case of trial and error.

In general, I was always advised that the tabs should be used to correct a "leaning trim" inother words use the tabs to keep the boat upright. Use the leg to raise/lower the bow.

Problem with tabs is that they do cause drag and therefore will affect your fuel consumption if over used. I try to use mine to get on the plane, then back them right off apart from what I need to get the boat upright.

A good way to experiment is to get on the plane, then set your revs to a comfortable speed, watch the log and adjust the leg/tabs a little at a time and see the effect it has on the speed. when you have found the optimum trim, you should have maximum speed at minimum revs if you see what I mean.

Be careful with using tabs at speed though as you can put the boat over to quite an alarming angle if you're not used to them. ( I know cos I did it with the wife on board and she doesn't let me forget it)

Hope this helps a bit

Good luck

JH

 

[Guest]

Adrian

I agree with all the other posts except that if you have Volvo duo-props then they should be trimmed to 0 to prevent cavitation burns to the outer prop. You then use the tabs to take the nose down to the correct attitude. The best way to experiment is to keep the revs and course constant and adjust the tabs until the boat feels comfortable this should be when the GPS reads the highest speed for the revs.

Experiment but use the info given in the posts as a starting point.

Colin

 

[adrianm]

Thanks for all the help. The mistake I was making was leaving the legs alone and messing about with the tabs (my ICC instructor told me not to bother with the legs !!). I tried it the other way round yesterday and the difference was incredible. Mind you I've got to remember to trim the legs down a bit before doing a sharp turn, skidding sideways is not my idea of fun!

In case anyone is interested the boat is a Sealine S37 with Mercruiser D4.2's and Bravo three sterndrives.

 

[Guest]

Go to www.boats.com and serach entire site for trim/trimming, etc and they give very good advice!