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Author Topic:   Performance of 16-7 with C-90 Yamaha
JimU posted 03-21-2001 10:12 AM ET (US)   Profile for JimU   Send Email to JimU  
I'm running a 13 1/4 inch 15 pitch SS Stilleto 3-blade prop on my 90 Yam on a 16-7 Whaler. The boat is the boat is a 1971 model. According to my GPS wot produces 41-42 mph at 5600 rpm. How does this compare to your experience? I read on some posts that a 75 yam/merc produces 44 mph. What gives?
Chesapeake posted 03-21-2001 12:05 PM ET (US)     Profile for Chesapeake  Send Email to Chesapeake     
Jim: My new Yamaha is not yet on the boat, so I am unable to answer. I would appreciate your thoughts on a subject.

A '71, so I presume you have the old mahogany console. If so, how did you arrange your guages and switches on the "cutouts" on the dash front? Hope you wouldn't mind sharing your thoughts on where the ignition switch and tach are located.


JimU posted 03-21-2001 02:06 PM ET (US)     Profile for JimU  Send Email to JimU     
Bob, my boat did not have a console. I built one and had it glassed by a local fiberglass shop. My approach to laying out the instruments was to keep the speedometer and tach close together and to mount them so they were visually balanced with the other instruments. My controls are binnacle mount controls, I mounted the key switch right below the main F-R control box. Jim

Chesapeake posted 03-21-2001 06:23 PM ET (US)     Profile for Chesapeake  Send Email to Chesapeake     
Jim: Thanks. I now recall reading the thread where you discussed the console. I really wanted to do that as well, but had no clue as to who or where to go in Chicago for the glass work. After all, this ain't Florida.

As a fairly decent carpenter-wanna be, I was drawn to building a custom console that matched my needs. How did it work out for you and what does (if you don't mind my asking) a fiberglass person charge for the service? I am anxious to see your pics.


Clark Roberts posted 03-23-2001 10:46 AM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
Jim, I can't explain it but I have never gotten more than 42mph on any of my 17 Whalers with 90 yamahas.. I have owned 5! All ran 15" Yam SS props and all ran WOT at around 5400-5500rpm... Engine would not swing a 17" pitch... A friend used to get about 40 with a 70 yam.. go figure. My fastest 17 was a 1980 Newport with a 90 Merc (1996) swinging a 20" pitch Quicksilver High Five SS prop to about 50mph. I know of several 17's with 75 mercs that do 42-44 and one that hits 45mph per GPS... Try raising your engine a couple of holes! Clark .. The Old Man and the Sea
JimU posted 03-23-2001 02:20 PM ET (US)     Profile for JimU  Send Email to JimU     
Clark, thanks for the info. Question: With my present setup, the cavitation plate on the engine is about an inch and a half ABOVE the height recommended by Yamaha who recommends that it be at or below the bottom of the keel at the transom. Thus the engine is a little high according to Yamaha. What problems will I run into if I raise it 1-2 inches? Thanks. JIM
Clark Roberts posted 03-23-2001 02:57 PM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
Jim, I didn't suspect that your engine was already raised! Problem with raising too high is water pick-up.. Even as it stands now you may benefit from a Doel-Fin to put a cap on the prop... maybe raise it one more hole... won't hurt to try.. but 42 may be max you're going to get...Happy Whalin' Clark
JimU posted 03-27-2001 01:53 PM ET (US)     Profile for JimU  Send Email to JimU     
Bob, I built the console from 3/8 plywood. Dimensions 19" deep X 34" high X 30 wide. the material cost less than 50 bucks. To have it glassed costs about $5 per square foot of area. Good luck. JIM
Chesapeake posted 03-27-2001 03:11 PM ET (US)     Profile for Chesapeake  Send Email to Chesapeake     

That seems very reasonable. What type of finish - does this include gelcoat or epoxy finish / paint? I won't re-do this Nauset again for the foreseeable future (I hope), but their is always the next one...


JimU posted 03-27-2001 05:44 PM ET (US)     Profile for JimU  Send Email to JimU     
Bob, the fiberglass man put on a gelcoat finish that matched my interthane paint job. The gelcoat finish was included in the price. JIM P.S We glassed the console inside and out with about 1/8". When you figure the square feet don't forget that you will have to double it if you are going to glass both sides. I think my console was about about 25 square feet on one side--a total of 50. I paid the guy $250 for the job. When you build the console, run a router around all edges to round them off. It will produce a much nicer result. JIM
Chesapeake posted 03-27-2001 05:50 PM ET (US)     Profile for Chesapeake  Send Email to Chesapeake     

That is neat. I will be anxious to see a picture in Cetacea when you have her complete. Please let us all know.


andygere posted 03-28-2001 11:33 AM ET (US)     Profile for andygere  Send Email to andygere     
There is no need to fully fiberglass the inside of the console. Just saturate it in resin to keep water out. The resin can be applied with a foam roller and tipped out with a foam brush. The cloth will just add weight and the extra strength in not needed. Also, I would use epoxy instead of polyester resin. It's more flexible, and will form a much stronger bond with the plywood. I used the MAS brand on a stitch and glue kayak I built a few years ago.

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