HP and Length

[mossygo]

I have a 1970 15ft gregor with a 20horse. Never really paid much attention to short/long shaft before but realized my transom is 15.5" and I believe my motor is a long shaft, 18"? Would a few inches make much difference? My other question is, I am trying to fix my current motor but I have an opportunity for a mid 80's 25hp short shaft. If I remember correctly, motor size requirements weren't established until 1972 which might be why I don't have a plate so would a 25 be fine? The previous owner had the 20 horse and a 7.5 horse mounted at all times on the boat. But I imagine that motor standards weren't applied for weight issues but more for boat control.

 

[F_R]

Re: HP and Length

Are you sure your motor is long shaft? Long shaft is for a 20" transom (really more like 21" on most boats)

The anti-cavitation plate on those old motors normally run one or two inches below the boat bottom. That design goes way back to when boats were made of wood and had keels. If you try to jack the motor up too high you will get a lot of cavitation and ventilation because the lower unit and propeller shapes were not computer designed and are not as efficient as newer motors.

 

[tashasdaddy]

Re: HP and Length

you 20 is the proper motor for that transom, i see nothing wrong with going with the 25. 15 ft boat should handle it fine.

you may pick up just a little with the 20, buy putting a 1 x 2 spacer on top of the transom.

 

[jpmurphy]

Re: HP and Length

I have a 1988 15.1" alum welded Gregor. The capacity plate states max hp @ 35 hp. Just bought a 35hp. Can't tell you how it does as I haven't got it wet yet. Try Gregor.com. They have a contact us button. With year and model number they can probably tell you the mfg suggested max hp.

Hope this will help.

 

[mossygo]

Re: HP and Length

Been in contact with gregor via email and they said that the model number on my registration doesn't match a gregor. They said it starts with GBC which I later found in a different area on the registration so I emailed that back to them but they still don't think it's a gregor? So, no such luck with HP rating. I'm positive it is a gregor, I'm just finding it odd that they are giving me issues. So how has the 35 horse worked out for you? Any weight issues?

 

[Whoopbass]

Re: HP and Length

I have a 30 hp on my 15' 1992 Gregor.
The boat is modified into a bassboat so its pretty heavy with all the extra wood, batteries, trolling motor, tackle, etc.
My 30 hp Suzuki pushes the boat well and I haven't had any issues. It does 30 mph gps on a good light load day.

 

[mossygo]

Re: HP and Length

I've modified mine into a bass/duck boat as well. When I bought the boat the previous owner had a 20hp and 7.5hp 2 stroke mounted. I went into a local boat shop today that sets up package deals and they suggested a 25-30hp would be fine as far as hp rating. I suppose I will be trying to find the 25. My concern now is being able to troll with it. I don't think I'd feel safe putting the 7.5 on there as well. Thanks for the info.

 

[jpmurphy]

Re: HP and Length

Been in contact with gregor via email and they said that the model number on my registration doesn't match a gregor. They said it starts with GBC which I later found in a different area on the registration so I emailed that back to them but they still don't think it's a gregor? So, no such luck with HP rating. I'm positive it is a gregor, I'm just finding it odd that they are giving me issues. So how has the 35 horse worked out for you? Any weight issues?

The HIN (Hull ID Number) which is stamped on the right outside of the transom (on mine) does in fact start with GBC. If yours does not, then it probably is not a Gregor. I would think that a 15 to 16 foot, alum boat with average weight load would be pushed just fine with a 30 to 35 hp motor. The 35hp I bought had some issues so I never got it wet. Sold it a few weeks ago. Now I'm waiting on a 25hp rude to be delivered. I wanted a 35hp, but none were available at the time I was shopping. I should have this new one wet in a few weeks as I'm just now finishing up my rebuild. I'm shooting for the first week of June, wind on the lakes permitting.

Oh yeah, if you found a number on your registration with GBC, it should be a Gregor. The clerk at the Mfg may just be too new to know how to research the older models. Like I previously mentioned, they had a fire a few years back and those records may not be available to research.

Mine is a 1988, 15' 1" in length, all alum welded, BMT model, with a plate that sez 35hp max. Hope all this helps you somewhat.

 

[mossygo]

Re: HP and Length

The HIN (Hull ID Number) which is stamped on the right outside of the transom (on mine) does in fact start with GBC. If yours does not, then it probably is not a Gregor. I would think that a 15 to 16 foot, alum boat with average weight load would be pushed just fine with a 30 to 35 hp motor. The 35hp I bought had some issues so I never got it wet. Sold it a few weeks ago. Now I'm waiting on a 25hp rude to be delivered. I wanted a 35hp, but none were available at the time I was shopping. I should have this new one wet in a few weeks as I'm just now finishing up my rebuild. I'm shooting for the first week of June, wind on the lakes permitting.

Oh yeah, if you found a number on your registration with GBC, it should be a Gregor. The clerk at the Mfg may just be too new to know how to research the older models. Like I previously mentioned, they had a fire a few years back and those records may not be available to research.

Mine is a 1988, 15' 1" in length, all alum welded, BMT model, with a plate that sez 35hp max. Hope all this helps you somewhat.

Yes it does. I did notice on gregor's website that it hasn't been updated since 2007(at least that's the newest model shown) so the fire must have hurt em pretty bad. Mine sounds like the exact same boat at 15.1 but 18 years older.