max HP rating

[mellowyellow]

how do they figure max HP on different hulls?<br />my cousin and I both have 16' bowriders, his is<br />rated for 85 and mine for 135...anyone know why?

 

[blifsey]

Re: max HP rating

Search here for the link to the Coast Guard document that details the "formula" for figuring max HP on home built boats. I've ran it on an older aluminum v-hull type jon boat and got within a few HP of the tag on it. In addition to LOA, it takes beam and few other factors into consideration. Another thought, are the boats drastically different in their mfr year or hull type? The mfr may have put a lower rating on one due to construction maybe?<br /><br />BL...

 

[mellowyellow]

Re: max HP rating

hello Hotbyte,<br />boats are VERY similar 16' tri-hulls mine is a '72<br />sea sprie and his is a '79 ? (some Fla. mfg.)<br />will have to look at his beam now and see if that's smaller.

 

[Boatist]

Re: max HP rating

Beam, transom height and weight of boat are factors. Also construction and strength of the hull and stringer system. Bottom line is rated for your safety and if buying a boat one of the thing you should check.

 

[MGuckin]

Re: max HP rating

lenght x width x 2 - 90 will get you close. <br />Integrity and hull design are the real determining factors which are scrutinized under very lengthy testing procedures.<br />This is the link to the testing procedure.<br /> http://www.access.gpo.gov/nara/cfr/waisidx_99/33cfr183_99.html

 

[sho305]

Re: max HP rating

My Bayliner 16' OB BR is rated for only a 90hp. I found out why when replacing the transom and a chunk of floor. The transom was only a 18" wide piece of 3/4" doubled only at the clamps. And the floor stringers consist of only two 1 x 4's! Yes, 3/4" by 3.5" on each side is all the wood you get.<br /><br />I guess it should be pretty light though for that 85hp Force...