Why rubber bellows?

[SeaDooSam]

Just had an epiphany, why the heck do they make bellows out of rubber? Why not flexible plastic pipe or something that doesn't go. There has to be some heat resistant plastic. Why do they need to be rubber!?

 

[Baylinerchuck]

I think rubber is most likely the best material due to its combination of flexibility, form memory rigidity, and endurance. I would think if there was a better material out there an aftermarket company would be making it and raking in a ton of money.

 

[wrvond]

Silicone.
Surely has to be better.

 

[Scott Danforth]

vulkanized rubber is still the best material for the job. same reason why tires on your car are still rubber

the material has excellent tensile strength, excellent flexural strength, excellent properties when in contact with most oils, solvents, etc. its good with heat and will decompose after 50- 80 years or so.

Plastic is around forever after it has lost its usefullness

Silicone is actually an elastomer that needs to be cured to keep it from reverting back to its gel like state. It would need to have a nomex or other backing for any strength which would take the cost and make it about 10-15 times more than rubber.

 

[proshadetree]

I will agree that silicon would cost more but I think I would like it a lot better. Especially on houseboats that have to be pulled to replace cracked rubber boots. The cost of the boot would still be low compaired to a haulout.

 

[Scott Danforth]

Silicone has a life expectancy only slightly better than rubber. and on your outdrives you still have the annual inspection required of the gimbal and u-joints along with the gear change so you dont gain anything. you still need to haul out.

 

[proshadetree]

Houseboats are not hauled out every year. Most go 8 to 10 before they get pulled. Some much longer. Steel hulls in fresh water have been in the lake for 15 to 20 before the get rehulled or sink.It is just the nature of the beast.

 

[proshadetree]

The only silicone I have experience with is automotive hoses. They dont hold clamp tension well and if over tighten they tend to split. A viable alternative to rubber bellows would be a welcome change.

 

[dingbat]

A viable alternative to rubber bellows would be a welcome change.

It's called an outboard....lol

 

[Scott Danforth]

Houseboats are not hauled out every year. Most go 8 to 10 before they get pulled. Some much longer. Steel hulls in fresh water have been in the lake for 15 to 20 before the get rehulled or sink.It is just the nature of the beast.

most houseboats I know of get hauled out yearly for drive maintenance, bottom maintenance, etc watched 20 boats get hauled out for service when I was at Lake Powell October of last year over a 2 day period

It's called an outboard....lol

exactly. a houseboat will move the same speed with 100 or 1000 hp.

 

[SeaDooSam]

It's called an outboard....lol

Good point! Can't deny that lol

 

[proshadetree]

Many more dont get hauled out, Old Hickory, Cordell Hull, Cumberland are just a few around here. I broker boats part time. We have sold boats from all over the east from Michigan to Florida most if not all dont get pulled annually. Most dont get the maintenance they need either. Brokers tend to know who to use when getting a survey to sell a boat, I always recomend a good man to survey before a customer buys a boat reguardsless of when the last one was done. Most houseboat buyers want the engines underhood to have the rear of the boat useable for jet skis, swimming ect so outboards are not that popular on newer highend houseboats. Not all houseboats are square hull barge types. Mine is a v hull and will run 25 to 30 allday long if i keep the hull clean. Overpowering a barge will only bring water over the nose but it will make it faster untill that happens.

 

[bspeth]

no one pulls their houseboat every year just to inspect the transom.

 

[achris]

Mercruiser bellows usually last 10+ years. I don't see them being rubber as a problem. I do see not checking the water pump impeller and clearing the intakes of marine growth as a bigger problem....

 

[SeaDooSam]

Mercruiser bellows usually last 10+ years. I don't see them being rubber as a problem. I do see not checking the water pump impeller and clearing the intakes of marine growth as a bigger problem....

Really? Everyone has been telling me 3 maybe 5 yrs max

 

[thumpar]

Really? Everyone has been telling me 3 maybe 5 yrs max

I went 7 and I don't know how long they were on before I got it.

 

[achris]

Really? Everyone has been telling me 3 maybe 5 yrs max

Really. The current ones on my boat are from new, 10 years old, and still looking good. The previous engine is now 22 years old and only on its second set. Another friend with a 1995 V6 is also on his second set.

BUT, if you're using non-genuine, all bets are off.

Chris...........

 

[SeaDooSam]

Are your boats in the water the whole time? Mine is out half the year (winter) maybe that reduces the life

 

[proshadetree]

Mine are Sierra marine. Stuck them on there when I built the boat. 7 to 10 years ago. Sierra on my Dana drives on the houseboat too. Dana dont make them anymore. 4 or 5 years ago. Both still look new. I have seen silicon hoses on late 80 early 90 mustangs that have Motorcraft on them still in use. Only reason I would consider silicon to be the better hose.

 

[bajaunderground]

What about poly-urethane? I know they have been using it for bushings and bump-stops on cars/trucks for years (aftermarket). I know it's a harder msterial, but they do tend to last longer in that environment? Might not be flexible enough would be my guess? If possible, we could have custom colors!!