View Full Version : Weight and Horsepower
I am curious on how a boat manufacturer rates a hull for a certain HP rating. Is it based on what the hull can handle? Or the weight of the motor and transom strength? Certain motors weigh more than others (eg. 150 Merc vs OMC and Yamaha)so if a hull is rated for a 150 does that mean every 150 no matter what the motor weighs? There can be a big difference here. OMC has a 370lb 150hp and Merc's 150hp is 450lb's. Is this something to consider when upgrading or is it nothing to be worried about?
Thanks for your feedback.
Jeff
Actually, the manufacturers really don't rate the boats at all.
The Coast Guard does the rating. The Coast guard has a formula for HP rating - that is sent to all boat manufacturers. Before the Coast Guard will sign off on a HP rating on a boat, the manufacturer needs to send the specs on the boat hull to them for final approval.
The hp is based on several factors - hull length, beam, freeboard, console steering, or tiller steering - and transom depth to name a few.
If you do a search on the Coast Guard site - I expect that you will be able to find the table with its formula and requirements.
Because the Coast guard changes these tables from time to time, and the intrinsic boat construction changes over the years - you might find a hull rated with a certain hp, yet a seemingly identical hull - could very well have a significantly different hp a few years later.
Take care and enjoy your shopping.
REW
Bullfrog
02-28-2001, 04:21 AM
Actually, the ABYC is the rating organization. The American Boating & Yachting Council. They take into account beam and length, that's why you see the overall length on some boats "stretched" in the bow and stern with several inches of rubrail or combing. They have lots of interesting rules and regs, and perhaps someone from that group could comment.
Heavy motors can hurt the transom. Your transom might not be heavy enough for the heavy 150 opti. I think the EFI is lighter.