1974 18' Cobalt Trihull

[tkinney]

Hello All,

I'm interested in getting a boat for myself and my family (wife and 10 year old son) to use for some fishing, skying, tubing etc. I'm quite mechanically inclined but I've never owned a boat. I've come across a 1 owner 1974 18' Cobalt. Below is the information in the ad and some of the pictures. What would you experienced boaters tell someone like myself about a boat like this? Should I be concerned about the age? The hours seem relatively low but I don't know anything about out drives. Can I service this one, get parts or replace it down the road if it needs something?

Owned this 18' Cobalt open bow deep V Tri hull since it was new, 1974. Boat is power by a 307 sb Chevy with 245 HP and OMC in-out drive. Boat has 615 hours on it. Boat has always been stored in the garage. Has two props 13 pitch and 15 pitch. Trailer has a swing tongue so it will fit in a standard depth garage at 19.5 feet. Trailer also, has new wheel brakes and new surge brake master cylinder. Tongue has two brake-away chains for added safety. Boat runs strong and pegs speedometer at 50 plus miles per hour. We used the boat mainly to water ski and some fishing. Text me at 2-09- 60-4 31-94 for any questions.

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[AsLan7]

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So glad you found us tk…..

That original owner Cobalt appears to be in great shape for her age. Normally stringer or transom rot would be a thing with a boat that old but the original owner appears at first glance to have kept her clean. With your mechanical knowledge she’ll be easy to work on, especially with all that room around the engine.
Change fluids, spark plugs and impeller. Fire her up.

Oh and check for tire rot and bearing lubrication.

And welcome aboard mate!

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[tkinney]

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So glad you found us tk…..

That original owner Cobalt appears to be in great shape for her age. Normally stringer or transom rot would be a thing with a boat that old but the original owner appears at first glance to have kept her clean. With your mechanical knowledge she’ll be easy to work on, especially with all that room around the engine.
Change fluids, spark plugs and impeller. Fire her up.

Oh and check for tire rot and bearing lubrication.

And welcome aboard mate!

.

Thank you, what would be the best way to check the condition of the transom other than of course poking around on it and looking for soft spots? Pull the motor cover and look from the inside? Can you explain what the stringer is?

I've done a fair bit of reading but there just doesn't seem to be a lot out there on these older boats, I mean sheesh it's 50 years old! Plugs no problem, the impeller I take it is what is responsible for driving water through the cooling system right? Sounds like I should be replacing that every other year or so?

[tkinney]

One more thing for the group, $3,900 a fair price? Seems like a lot of boat to me for that price. I've been watching it, he started out a couple weeks ago at 5k so I think the seller is motivated.

[bruceb58]

Personally, I would skip that boat. That electric shift OMC is going to be a world of problems down the road. They were horrible at sealing, the electric shifts springs go out, the magnets go out. You can't run trimmed up. The tilt system leaks like a sieve. The ball gears wear and you will be lucky to find OEM ball joints anymore.

Stick with boats with Mercruiser or Volvos.

How do I know all of this! I had a 1975 OMC with a 307 Chevy motor.

OMC stands for "Out of business Marine Corporation".

[AsLan7]

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So glad you found us tk…..

That original owner Cobalt appears to be in great shape for her age. Normally stringer or transom rot would be a thing with a boat that old but the original owner appears at first glance to have kept her clean. With your mechanical knowledge she’ll be easy to work on, especially with all that room around the engine.
Change fluids, spark plugs and impeller. Fire her up.

Oh and check for tire rot and bearing lubrication.

And welcome aboard mate!

.

Thank you, what would be the best way to check the condition of the transom other than of course poking around on it and looking for soft spots? Pull the motor cover and look from the inside? Can you explain what the stringer is?

I've done a fair bit of reading but there just doesn't seem to be a lot out there on these older boats, I mean sheesh it's 50 years old! Plugs no problem, the impeller I take it is what is responsible for driving water through the cooling system right? Sounds like I should be replacing that every other year or so?

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Yes poke around looking for soft spots or delaminating, bubbles, and or waviness in the gel coat. Fiberglass is porous and these symptoms can indicate water damage.

Stringers are essentially the frame of the boat. Basically boards that run the length of the boat and a few horizontal sections to form a “frame”. The fiberglass mold wraps around the stringer frame. Over time wood stringers tend to rot depending on water intrusion. Look for access holes or covers that can be removed and using a mirror and a light look at the areas you can see.

Remember this is more of an antique that will need maintenance and TLC. If you’re looking for turn key definitely move up to fuel injection (>1995ish). If nostalgia is your style with upkeep projects at times, this will fit your bill.



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[Kate]

"That electric shift OMC is going to be a world of problems down the road."

Didn't know that. Thanks. Can it be replaced with, say, an A1G1?

"The OMC ball gear system doesn’t allow the drive to be tilted/trimmed separately from the engine. The complete engine and drive assembly must be rocked back and forth within the boat to trim the drive and propeller. The front of the engine is lifted or lowered to change the propellers angle of attack." (https://www.glmmarine.com/30yearsomc.html)

Yikes!

[bruceb58]

Yes...and that tilting of the whole engine assembly is a major kluge. I don't think the boat in this post has that...at least I don't see it in the picture.

I don't know what an A1G1 is. Problem with trying to convert to another drive system is that the hole in the back of the boat is this huge round hole. The entire transom needs to be rebuilt to make it work with a Volvo or Mercruiser.

[tkinney]

Well this is kind of a bummer.... That sure is a nice boat but I want something I can have fun with. I don't mind working on something if it needs repairs but a lack of parts availability means repairing the OMC drive when it needs it may not be an option. And I'm not interested in doing the work a swap would require. Too bad.

Thank you all for the information, that's exactly why I came here and asked. Probably saved myself a bunch of headache at some point.

[Titaniumboy]

The ball gears wear and you will be lucky to find OEM ball

My 1977 Beachcraft has the OMC electric shift outdrive and my childhood buddy who ran a boat shop for 40 years said that not many of these electric shift outdrives are still working.

The ball gears really do not wear much IF you never run the outdrive in the raised position. Inspecting the wear on the ball gears is easy to do. The ball gears are still available on ebay with New Old Stock OMC ball gears showing up on a fairly regular basis along with new ball gears made by Sierra.

I asked my buddy if I should buy a set of replacement ball gears just to have on hand. He said I wouldn’t live long enough to wear out my ball gears as long as I did not abuse them by running with the outdrive raised.

[bruceb58]

Thank you all for the information, that's exactly why I came here and asked. Probably saved myself a bunch of headache at some point.

You dodged a bullet! Worst drive ever made.

[tkinney]

Thank you all for the information, that's exactly why I came here and asked. Probably saved myself a bunch of headache at some point.

You dodged a bullet! Worst drive ever made.

That's why when you're looking to by something you know nothing about, especially a 50 year old boat you do some research! Too bad it's not a mercruiser because I really liked that boat especially in that condition at that price. I suppose with a mercruiser he might would've asked more.

[bruceb58]

That's why when you're looking to by something you know nothing about, especially a 50 year old boat you do some research! Too bad it's not a mercruiser because I really liked that boat especially in that condition at that price. I suppose with a mercruiser he might would've asked more.

With a 50 year old boat, the drive is just the beginning of what you need to look at. As mentioned earlier, anything with wood in it can be a problem...transom, stringers, floor, seat bases...

Another thing with these older boats are the steel fuel tanks if they have them.

[tkinney]

That's why when you're looking to by something you know nothing about, especially a 50 year old boat you do some research! Too bad it's not a mercruiser because I really liked that boat especially in that condition at that price. I suppose with a mercruiser he might would've asked more.

With a 50 year old boat, the drive is just the beginning of what you need to look at. As mentioned earlier, anything with wood in it can be a problem...transom, stringers, floor, seat bases...

Another thing with these older boats are the steel fuel tanks if they have them.

I would’ve checked the wood and those structural things and skipped off those were problems most likely. As for fuel tanks the motor etc. I would be fine refurbishing those. Here’s my truck, I don’t want to put the amount of love in that boat that’s been put in this truck.

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[bruceb58]

As for fuel tanks the motor etc. I would be fine refurbishing those.

The problem with fuel tanks, depending on the boat, you practically have to rip the floor apart to replace the tanks. The tanks are placed between the stringers before the floor and the cap are put on during manufacturing. Most boats from the mid 90s on are usually all polyethylene tanks so not as much to worry about them compared to older aluminum and steel tanks.

Out of curiosity, what part of CA are you in?