New To Me: 1985 PolarKraft CGS1451

[LDUBS]

Sorry I can't help with that trim wedges you mention. It is simply outside my knowledge.

 

[Axhammer]

Nice boat, it has the same bloodlines as my 1992 Polar Craft MVT-1751. Both are very similar in appearance.

A boats length and width is often a factor when max HP rating is determined.

There are two other factors that allow for a higher HP rating to be assigned from the factory, when comparing two boats with the same length.

A 20” transom and remote steering will allow for a higher HP rating.

Your boat appears to have a 15” transom. Your boat doesn’t look like it ever had remote steering, so these two features don’t really come into play concerning your boat.

If a company made two identical 16’ boats, that were the same with the exception of the transom height and one having remote steering, the one with the remote steering and long shaft engine would be rated for more HP.

If you replace your transom, and your new one ran straight across the top of the stern, without the dip, I’m pretty sure it will measure 20” for a long shaft engine.

Since your transom needs work, and you have a LS engine, I would build the new transom to run straight across the stern. This way your engine will be better suited for your boat.

Keep that mini jack plate, you may want to use it. After the transom has been replaced and you put the motor back on, you will see where the cavitation plate sits in relationship to the hull bottom. Most engines are a little longer, so they run deeper that actually required.

My guess is that mini JP Would be perfect with a 20” transom and a LS engine.

 

[kflavin]

I checked the CG formula for my boat, and it comes to exactly 45 HP for 15" transom, and 13'11" long by 5'11" wide.

Its the Coast Guard Rake hull that gives it the rating advantage.

If it was a true flat bottom like the other 1451's PolarKraft made, it would spec out at 30HP with the CG formula.

 

[kflavin]

Nice boat, it has the same bloodlines as my 1992 Polar Craft MVT-1751. Both are very similar in appearance.

A boats length and width is often a factor when max HP rating is determined.

There are two other factors that allow for a higher HP rating to be assigned from the factory, when comparing two boats with the same length.

A 20” transom and remote steering will allow for a higher HP rating.

Your boat appears to have a 15” transom. Your boat doesn’t look like it ever had remote steering, so these two features don’t really come into play concerning your boat.

If a company made two identical 16’ boats, that were the same with the exception of the transom height and one having remote steering, the one with the remote steering and long shaft engine would be rated for more HP.

If you replace your transom, and your new one ran straight across the top of the stern, without the dip, I’m pretty sure it will measure 20” for a long shaft engine.

Since your transom needs work, and you have a LS engine, I would build the new transom to run straight across the stern. This way your engine will be better suited for your boat.

Keep that mini jack plate, you may want to use it. After the transom has been replaced and you put the motor back on, you will see where the cavitation plate sits in relationship to the hull bottom. Most engines are a little longer, so they run deeper that actually required.

My guess is that mini JP Would be perfect with a 20” transom and a LS engine.

Thanks for the advice… this is exactly my plan more or less!


And yes the Honda is like 21.7 inches and the transom has a 15 degree rake which looses a little of the true vertical height.

So there is a very good chance i might be using the plate in the end.

 

[Axhammer]

My MVT-1751 (Metal, V-hull, Tunnel) is rated for less weight and power, despite being 3’ longer with a 20” transom and remote steering. I wonder if the tunnel hull has something to do with the rating, or maybe the rules changed between 1985 and 1992?

I have a 1992 1648 with a 15” transom that is rated for 35 HP.

What does CGS stand for in CGS-1451?

I saw a custom tiller extension made out of two pieces of PVC tube the was hinged in the center that worked pretty slick.

 

[kflavin]

Remote Steering and at least 20" Transom Height HP =(2 x Factor) -90 115 hp

No remote steering or less than 20" transom Height

For flat bottom hard chine boatsHP =(0.5 x Factor) -15 40 hp
For other boatsHP =(0.8 x Factor) -25 60 hp

Interesting... perhaps during testing Polar Kraft chose to use the most conservative rating for a 17' x 6' hull?

 

[kflavin]

My MVT-1751 (Metal, V-hull, Tunnel) is rated for less weight and power, despite being 3’ longer with a 20” transom and remote steering. I wonder if the tunnel hull has something to do with the rating, or maybe the rules changed between 1985 and 1992?

I have a 1992 1648 with a 15” transom that is rated for 35 HP.

What does CGS stand for in CGS-1451?

I saw a custom tiller extension made out of two pieces of PVC tube the was hinged in the center that worked pretty slick.

Im not entirely sure what CGS stands for exactly, other than I expect it has something to do with what some call the Coast Guard Bow? (Vee hull, square bow deck.)

 

[kflavin]

Remote Steering and at least 20" Transom Height HP =(2 x Factor) -90 115 hp

No remote steering or less than 20" transom Height

For flat bottom hard chine boatsHP =(0.5 x Factor) -15 40 hp
For other boatsHP =(0.8 x Factor) -25 60 hp

Interesting... perhaps during testing Polar Kraft chose to use the most conservative rating for a 17' x 6' hull?

Actually it is possible that your steering was added after the boat was built...

 

[kflavin]

Actually it is possible that your steering was added after the boat was built...

So, the more I think about it, I'd bet PolarKraft used the flat bottom number because of the tunnel hull. With less engine below the hull profile, there may have been a stability concern?

 

[kflavin]

Im not entirely sure what CGS stands for exactly, other than I expect it has something to do with what some call the Coast Guard Bow? (Vee hull, square bow deck.)

Ok, 10 minutes worth of googling Polar Kraft Models and pictures... I have an idea.
C-Jon Boat
G-Coast Guard Bow
S-15" transom (F-20" Transom)