1997 18 foot lund alaskan porpousing (90merc)

[batman99]

Re: 1997 18 foot lund alaskan porpousing (90merc)

I was thinking a 4 blade prop might be better! However the lakes i frequent are more often smooth than rough. Will i need to change the pitch when going to a 4 blade?

I buy my props from iboats online store. re: Boat Propellers for Sale, Stainless Steel Boat Props - iboats

Note: If going 4-blade, go 2P lower - compared to current 3-blade. On my boat, I use "3-blade 19P and 4-blade 17P". 3-blade for long distance cruising and 4-blade for tubing and low speeds. Both aluminum - for my shallow lakes and rivers. For me, Solars brand of prop works great.

Even with dollar conversion, cross border processing, I can buy props from iboats for LESS cost - compared to buying locally. But do price compare "to your door".

Hope this helps...

 

[Lundman83]

Re: 1997 18 foot lund alaskan porpousing (90merc)

Hmmmmmm. That does make sense. Ok!Thanks a lot guys!!

 

[Jdeagro]

Re: 1997 18 foot lund alaskan porpousing (90merc)

Hi Lundman83;

I am not sure that I could add much to what Batman suggested as he is dead on. Porpoising is a result of water pressure lifting the forward section of the boat easier than the stern because of the weight distribution. The bow rises as the water (squeezes / pushes) it up, then it falls back into the water. Typically this is minimized when the motor is trimmed all the way down which faces the prop in an upward angle lifting the stern. This adds pressure to keep the bow down. Adding weight to the bow can also help, but this added weight cost money since it will affect fuel consumption. Keeping the motor trimmed down also causes a loss of fuel economy as well as top speed since the prop is slipping. The prop is most efficient when perpendicular to the water surface.

A common quest that I get on a regular basis is "how can trim tabs make the boat go faster"? In and of themselves they do not, however, when the prop is at the correct running angle (perpendicular) and the boat runs smoothly both speed and fuel economy are improved. Let the trim tabs take care of boat handling and attitude issues and let the prop "propel". The position of Smart Tabs is regulated by speed and water pressure so they are always in the correct position.

It is like having a "Hull" that changes shape on demand.