What Prepurchase Survey consist of.
Very comprehensive type of inspection. It will cover structural integrity, electrical systems, propulsion systems, fuel systems, navigational systems and all systems within the vessel. Cosmetic appearance, out of water inspection, and sea trial. This survey will help you make a “Educated” decision on your purchase.
Insurance survey will consist of structural integrity, all systems within vessel and a bottom inspection if required by the insurance company.
12 volt systems on most boats are very complex but in reality the major item to make it simple is by having each engine battery, generator battery and house battery all isolated from one another. By this I am saying that if you have a alternator failure on one engine it does not kill the entire system. This can be accomplished by using isolators or combiners between house battery,generator battery and engine batteries. Only thing that will be common between them is the negative ground system. This allows batteries to be charged from all sources but not allow them to drain to each other.
Although as a marine surveyor we do not do engine surveys, this surveyor will check all these listed below and note any problems. I have an extensive mechanical background.
|Engine RPMS – Most boats I look at cannot reach max rated rpms and this can be detrimental to engine life. Exhaust gas temperatures go way high when engines are overloaded. Some folks believe they can cruise at a lower rpm and not worry about it but that is not correct. Engine should be propped to hit rated rpms +50rpms heavily loaded, this brings EGT down and motor runs like it should. On electronic diesels it can be more complex but a certified diesel mechanic can advise you. Proper propping helps fuel economy, ability to plane out faster and longevity of the engine. This can be one of the most important things you can do to keep your engine in good health. A brand new vessel can be overpropped as manufacturers prop it with no tuna tower or top, no fuel, no ice and gear. When propping always do it with the boat loaded to the brim like you were leaving to go on a long trip.|
|Seawater side of the engine – All of the modern diesels need maintenance beyond changing oil. The seawater side needs special attention but if done properly then every 2–3 years you need slight maintenance. Rigging a freshwater flush system for flushing heat exchangers, aftercoolers seawater pumps and coolers will really make a difference in the maintenance on your engines and is very easily accomplished. Aftercoolers have a mix of different types of metals that can corrode in saltwater so by simply flushing them with freshwater it eliminates a lot of these issues. Aftercoolers that have corroded to the point of leaking will allow saltwater to be ingested into the engine causing devastation.|
|Exhaust systems – Sometimes factory designed exhaust systems will allow water to enter the turbo causing havoc on the turbo. Exhaust systems need careful inspection to make sure this does not happen.|
|Oil change systems – A good oil change system makes changing oil a breeze. On that note when you do your first oil change you should consult engine manufacturers specifications for exact amount of oil the engine should hold, then drain all the oil and fill the crankcase with the amount specified. Check the dipstick and make sure the stick is marked correctly, engines are installed at different angles in boats and a lot of times you overfill the engine by relying only on the dipstick. Personally I had QSC Cummins in my last boat that if you filled it to full on the dipstick it was overfilled by 4 quarts and would blow oil out of the breather making you think you have bad blowby and causing a mess.|
I suggest strongly that you invest $25 a year and join boatdiesel.com and read up on your particular engine. SBMAR.Com is a wonderful site and read all of the articles that Mr. Tony Athens has written on aftercoolers and every part of an engine, this site will teach you all you need to know on maintenance of your motors.