Before you rush out and buy an outboard motor check on the correct specification for your boat. Matching your boat to the power unit is important to enable you to get the best out of your boat and out of your budget. The transom on a boat is the flat vertical part of the boat at the rear end, this is where the outboard power unit will be mounted. The depth of the transom is measured from the base of the
The height of the transom determines the size of outboard motor that is correct for your boat, as the motor is integral to the operation of the boat what ever your purpose then it is important to get this right.A good Marine Supply outfit will advise prospective buyers about what is best but as the boat could be some distance away when you go to buy take a picture on your cell phone and measure the transom – don’t splash any cash on an outboard until your sure that it is right for your boat!
If the height of the transom is wrongly estimated, it can cause problems as the propeller/s may catch the boats tail end or be too high and not deep enough to reach into the water.Boaters of all levels of experience, especially newbies, should be aware of the dimensions of their boat.
Industry standards dictate that for short shaft motors the height of the transom should be 15 inches. Long shaft motors require a height of 20 inches, with extra long shaft motors needing 25 inches. Some sea going boats use motors that plus length motors at 30 or 35 inch shafts
Beginners are advised to opt for a standard mounting when deciding on which motor to buy, again good quality advice is essential before deciding what to buy
Generally, the anti-ventilation plate on most engines is aligned with the bottom of the vessel. This is measured by the propeller shaft being parallel to the vessel’s bottom. The motor will come with mounting holes and brackets that can be vertically aligned to allow for adjustment by the user.
More experienced boaters may opt for a lower mounted motor where as the professionals and very experienced amongst the community may opt for high a mounted motor. Opting for a motor that is lower on the transom may cause a large amount of spray, increase drag, reduce water clearance and have a negative effect on faster boats. Additionally, this can affect fuel efficiency. Low mounted motors are not recommended for the beginner
‘Trimming in’, ‘trimming down’, and ‘trimming out’ are all terms that a beginning boater should learn. Each one has a totally different effect on the performance of your boat