TOPIC: Motors - bolt on vs hang

This issue came up on a modern boat, but has relevance here as well. A friend of mine just bought a 15 ft center console with a 30 hp outboard. The outboard is hung on the transom but not bolted on. I am thinking, especially since she operates the boat in shallow water a lot, that it should be through-bolted as well. At what size hp should you start through-bolting the motor?

Well I'm only running an 8 hp on my fishing boat but she is bolted on as well.

If the motor is taken off and put back on each time the boat is
used, and small enough for one person to carry, then bolting it
on is not necessary. Other than that they should be bolted on.

Question is how much do you value your motor. There are times when a motor if not bolted down will actuall "twist" off the transom under load, if you're lucky the controls will keep if from becoming a fish crib. On motors that I have had under 35hp I used to put a safety chain on them, run the chain through the carry handle and the other end bolted to the transom. Use a paddle lock ot something to complete the setup. Also keeps the motor from being hijacked while you're quaffing a few cold ones at the local gin mill after a hard day on the lake.
Anything bigger I would bolt down.
Cal

My 1957 Johnson 35 HP motors are clamped on only. I don't think they can even be bolted on. It probably is a good idea to safety chain them to the transom, but I have not done so.

Andreas

thetudor,

I see NO good reason to bolt-on a BigTwin. - otoh, for "keeping semi-honest people honest", i do put a chain/padlock on them & padlock the trailer to the trailer hitch with a safety chain, too.

fwiw, i've never has a Johnnyrude even "threaten" to twist-off the transom in 50+ years.

yours, satx

Well I can guarantee I will be bolting all my motors. This past July the guy that works on my motors was returning my boat to our dock just around the corner from the marina. The boat is a 59 Wacanda and the motor was a beautiful Merc 450 that was running beautifully. On the way back to the marina the steering cables came loose from the motor and it twisted revving the motor and faster than you could blink your eyes it ripped of the transom unhooking itself from cables wiring etc. and went to the bottom - 100' down.

I just have to think that I have contributed to some nice new fish habitat.
Tom

I bolt on the big ones, 50s and 75s. I clamp on the smaller ones 40 and under. The only one I ever lost into the lake broke the bracket leaving the bolted part still attached to the boat.

The original V4's had screw-type transom clamps, and they were jumping off the transom so much that OMC did away with the screw brackets altogether and came up with the funky side-brackets which were used for many years.

Since you were forced to bolt the motor to the boat using those brackets, you were assured that the motor wasn't gonna jump off the transom.

One neat feature about those clamps that I never knew (until told by an old-timer); if you remove the stainless side-bolts, the brackets can remain bolted to the transom and you can lift the motor straight up out of the brackets. Pretty cool!

I've only ever had one motor go in the drink, when I was a kid messing around in front of the boat ramp with my 7.5 Elgin Twin on a 10' Livingston, doing donuts. Of course it wasn't clamped down tight enough and you can imagine the "sinking" feeling when it lept off the transom into the Briny Deep.

Wasn't too deep, though, a guy with scuba mask was able to locate and he drug it up to the house (a block away from the ramp). I flushed 'er out, dried the points, and away she went!

Another time, had an ancient West Bend Tiger Shark 80hp outboard on the back of my 14' Fiberform, it was just a "demo" so I hadn't bolted it down. Didn't want them nasty West Bend holes messing up my nice Tower of Power bolt pattern!

Well, we were haulin' down the bay, and the motor torque lifted it sideways, along with the boat. Very scary to have an overevving motor on the back of the transom, held up only by the control cables and a bit of tiller wire!

After that experience I will NEVER go out again without the motor being properly secured!

I'd say a 35 has more than enough torque to take a flying leap into the drink and who needs that fun?

Cheers..........ed

Here is one you might enjoy. Even though it was secured a Briggs and Stratten goes to the drink. Must be made out of some pretty tough stuff.

The clamp issue must have started with fiberglass boats. When the clamp feet could dent into the wood, I don't think there was as much of a problem. I've noticed the old 1941 Speedifour has a couple holes in the bracket dished out as though for a huge flat head screw. Perhaps I should take the hint.

I will bolt ANY motor that can take bolts. If it can't take a bolt, it gets a chain and a shackle. I've never personally had my motor leave my boat in 40-some years of boating, but our family has lost a couple of small motors in salty Hood Canal. I have heard about motors jumping into the boat, I can imagine that would be a few scary moments.

If you ask me, she should bolt it on, no question... and use a generous amount of 3M 5200 to seal the bolt/holes. Better safe than sorry.

Dean

steering cable snapped when I was hopping my Whitehouse down the lake with Mark 55 screaming wide open. Within a split second, the motor flipped sideway, wrenched itself off the boat and hit the drink at 6000 rpm. I pulled it out of the drink, remounted it, spun it over with plugs removed, then pu the plugs back in, and cranked her up. Ran on one cylinder and wouldn't go forward or backward. The motor had ingested water and stopped instantly. The top cilder stopped quicker than the rest and sheared the crank just under the top cylinder. I had made a beautiful mark 55 into a single cylinder motor that wouldn't go anywhere. The hidden question is: what if it had been bolted on? Instead of the motor flipping off, the boat would probably have flipped. Vonsider the clamps to be kind of a shear pin that could save your ass instead of just your prop!

"I see NO good reason to bolt-on a BigTwin"

My beautiful little 1957 Lark "35" came dangerously close to going in the drink last year. Lake was rough, but not horrible. That was enough for the engine to work it's way up on the transom. I only discovered the problem because the engine was cavitating badly. Turned aroung to take a look & the engine was about to fall off. I had checked the clamp screws 1/2 hour earlier in the day. The non - bolt OMC brackets can be modified to accept bolting. I added bolts to the bracket on the Lark to keep it from getting lost overboard. It's crazy not to secure them