Trimming tips

Hi guys<br />My question is: What are the basics to setting up the installation of the outboard on the back of the boat in regards to height on transom, angle, spacing, etc.<br />My boat is a 1970 Grew 15' fibreglass runabout that weighs about 1000- 1200lb (guess), with a 1971 60hp Johnson outboard without power trim.<br />I am finding that I cannot trim the motor out past the halfway point without the bow getting so high that I can't see without almost standing up. Also, no matter how I trim it, I cannot seem to eliminate TERRIBLE hull pounding in even slight swells or chop with normal load ( 2 adults at 190lb & 140lb, 2 20L tanks of fuel, 1 battery, and regular safety gear ) The tanks, and battery are at transom of boat on each side, and occupants sit about 1 1/2ft forward of center.<br /> I am thinking that the motor is not properly setup on boat, but I am not sure how to inspect for this. Any help would be greatly appreciated.

Re: Trimming tips

Hi Dogger,the cav plate should be about level with the bottom of the hull or slightly above depending on the prop you are running.Without power trim any set up you use will be a compromise.What do you mean by half way point?The trim travel I use on my boat would be about 15 deg in total probably less.You may have too much weight in the stern.The shape of the hull has more to do with hull pounding in chop than motor trim.If you have a shallow V it will pound more than a deep V.If you are getting alot of pounding slow down.hope this helps

Re: Trimming tips

Thanks Sharkcat,<br />The trim adjustment consists of 5 holes that have a rod through them, and anything above the third hole away from the transom is impossible to ride safely. The boat is a shallow V bottom. I should have mentioned that before.The prop is an aluminum 3 blade 13 1/4" X 17.<br />I just checked my cav plate and it is about 1/2" BELOW the bottom of the boat. Will this 1/2" cause problems?<br />Thanks

Re: Trimming tips

That 1/2" shouldn't give you the problems you describe, mostly it will just cut your top speed a bit. Trim tabs will help and the more you spend the more you will get. I have electric Bennets on my 21'cuddy and I love them. Other threads have spoken highly of the auto-adjusting spring loaded type and they're cheaper. Do a search in the forums on trim tabs and you may find a solution to your problem.

Re: Trimming tips

Dodger CDN;<br /><br />When your boat is on the trailer, you can lift the tung, ( might take a little effor) and raise the bow. However you can not lift the boat from the stern. What does this have to do with your porpoising and pounding? Except for ski boats like Master Craft which are balanced in the center, power boats are stern loaded, and the center of balance is in the last 30% of the boat. This means that the bow has a very effective leverage and any minor lifting action(waves) will push to bow up, and what goes up comes down. There are a number of methods to counter act the problem. The most common are not necessarily the best but here they are: trim the motor down as far as possible ( causes loss of speed and sensitivity to steering) ; add weight to the bow (same as above); use permanent trim devices such as fixed trim tabs or hydrofoils(causes too much stern lift when cruising and lifts boat from center causing port to starboard handling issues). The best way to create better balance is to use either helm adjsutable trim tabs, or self actuated Smart Tabs. Just like flaps on an airplane wing.