bertram31.com

This is on my B20 project.

I'm not sure if this is designed, or if this is the result of sitting on a short trailer.

Not sure if I should be concerned or handle it after repower if it seems to affect handling.

The hook is very slight and very symetrical.

Here is is:





Thoughts.

Ian.

personaly, i would not lose any sleep over it

i expected to see a picture of a gaff through something non fishy. i wouldnt worry about that either unless it worsens.

It's definately not going to worsen... New stringers are ready to go in.

http://simplifying.net/phpbb/viewtopic. ... 28&start=0

Over on the 25 site.

Ian.

randall wrote:i expected to see a picture of a gaff through something non fishy. i wouldnt worry about that either unless it worsens.

I was kinda Xpecting that myself...



I wouldn't be surprised if they glassed in a set of wedges. I remember lots of guys doing that back in the 80's...a cheaper alternative to Trim tabs.

My old B25 was on a crappy home made trailer I cobbled together out of house trailer axles and steel girders and the hull took a real bad hook after sitting on it for a few weeks......one day in the water and the hook was gone. Just the flex in the glass, don't worry about it.

UV

My concern (if I have one) is that the aft most 4' of stringers are out of the boat and will be re-installed this week.

Any hook that is there by design or not will be locked in place.

The rear rollers are just at the transom and some of the other rollers actually 'free wheel' right now. If it's going to come out, it has a few more days until my stringers are installed.

Thanks!

Ian.

My B20 sits at a slip, so I can't check mine for you. While I normally wouldn't worry about it, here I'd check to see how its supposed to be before I locked it in with new stringers/glass work. Someone has to have a B20 that can be checked.

My guess is the rollers, they are really bad about point loading....I hate um. A good set of bunks, fitted correctly are the best way to support a boat on a trailer. In the search for my hull I looked at several 25's. Every one without fail that was on a trailer with rollers was deformed from the point loading, some severely.

Most builders that incorporate a hook or a rocker into a hull do so on the keel as well, so that would really be an area to check as well, but like everyone said...no big deal. BTW hooks will get you on plane faster!

Ian.. don't blame the shade tree surveryor.

Don't know about the B20; but the early 31B's had a hook left over from when they used the wooden hull for the fiberglass hull plug. Bruce of Starship ground his out to improve running angle.

Second time in two weeks I have heard this. Was with a friend looking at 31's and a broker told me about it on early 31's. He said he had it removed (straightened) from his 1962 fly bridge and increased the speed rather appreciably. Never rode in his boat but his story seemed a bit far fetched. Has any one had experience with this? He was talking 38 knots with Cummins 210's and three-bladed props. Said he took four-bladed off.
While he was telling this I had the wish for hip boots instead of deck shoes.

Where did you wade through that Mikey?

210s in a 31 going 38 knots with three blades? Off a cliff maybe. I call "POO POO" on that.

Baloney! I have 210's with 3 bladed Nibrals and cruise at 21-2 knots. No way in hell he even hit 30.

I second the call for bunks rather than rollers.

As for your concern, I would only be concerned if the boat has a tendency to porpoise. I have no experience with the B20 but have recently read of the exact same cause/effect in other 20' boats (Whaler Outrage 20 in particular).
-Joe

Ian, I would do my best to straighten it out, and to pay particularly close attention to the straightness and crispness of the lifting strakes. I did this on the Baron and was really happy with the result. Of course I don't know how it would have been if I had not done the work.

I have a friend in NY that had one of the first 21' Challengers designed by George Linder later to become the 21' Superboat. He had a slight hook and spent a bunch of time and money to straighten out the hull. After all was said & done he picked 0 knotts. Granted back then we only had a oil filled spedo meter but no change in top speed or getting on plane.

If the stringers are out set up a jig and jack out the hook before glassing in the new stringers.

RussP

walterk wrote:Baloney! I have 210's with 3 bladed Nibrals and cruise at 21-2 knots. No way in hell he even hit 30.

It can be done. Just ask Randall. We did it in the Cape Cod Canal (going with a 6 knot current and a 15 knot tail wind).

On another note regarding hull bottoms... I just got a quote for soda blast for $3000. I quite politely told him he was out of the game with that estimate...

Wow.

I'm not sure the hook can be pulled out. I cannot really get the hull bottom to move when bouncing with full body weight inside the bare hull.

I think I'll let it go as it is, run her next season and address as necessary. I might even leave any real bottom work until next year as well. We'll see, I hate to time and money on a bottom job only to grind it off and remove a hook a year later.

We shall see how the project unfolds.

Ian.

$3000 for a 20 footer? Keep shopping. He's out of line.

no kidding on being out of line. $3000 is about 3X what I spent on the hull and trailer that came with the boat.

Mark - The hull was a great bargain and adventure getting it back. Not sure if you heard about the original trailer... barely made it into NJ. No worries though. Got a nice new 3800# trailer underneath her now.

Ian.

mike ohlstein wrote: It can be done. Just ask Randall. We did it in the Cape Cod Canal (going with a 6 knot current and a 15 knot tail wind).

yeah... we were going downhill for sure. later we found out it was a 5 mph zone.....better to be lucky than good.

i got a price for 1,000 to soda blast my 31, probably cost me a total of 3 grand after i finish the bottom with barrier coat and paint

I understand a hook from rollers but...

Is the glass protruding out further from the stern in that area...or just an optical illusion.

On the transom...Right above where the level is... the area to the right looks built up/out... then transitions back to the transom just above above the level. Maybe it's just me.

the apba race days of the mid seventies gave me quite a bit of experiance along the lines of bottom problems that can increase or degrease speed. i use a concrete tool called a "screet" . that is a aluminium 2" x 4" about 15' long . put it against the strakes from were it makes contact towards the bow to the stern ----repair then the flats .basiclly is doesn`t do anything for speed unless the boat is able to do at least 65mph.eliminating every 31 bertram. i did mine and it added nothing to speed . i had the time during winter lay-up and the hull was damn near on the money, strakes needed a little work .

Rawleigh,
This was a Broker who shall remain nameless since he exhibits all the other attributes of a lying m.f.

Well the only time my Bertram is going to see 65 is on the trailer behind the tow vehicle.

Ian.

Mine too, best I've seen on the water is 62.

Now 62 is moving in a 20 foot Bertram.

Best I saw was very high 50's. It was actually my old hull what was redone. 5.7 V8 with duoprop. Pretty cool to be fully up on stel at about 1800 rpm.

Ian.

furthermore at 90mph and above in a 24 degree deadrise boat (deep vee offshore raceboat) the boat with turn to the opposite side of the hook .taking the engines out of the equation because they are held in exact sync. due to electronics . props are "in velvet " every race.

i know it is rather stupid to answer to this brokers B.S. but you should know there is a "block equation " that engine buiders use. big dollar engine builders normally hold there high dollar expertise to specific type of racing,be it oval track , drag racing , offshore boat racing , short track stock car, extreme "street racing". he has to be right there or lose his dominants . a 210hp cummins cannot power a 12,000 lbs bertram 31 at 38 knots!! no after cooler would prevent a 6bt from making that kind of power.and the 3 blade versus 4 blade talk tell me he has a "paper asshole" a northern term ----to mean he cannot back his statement!!!!

As waltert said, No way with the the 210. With the 270's, 4 blade 20x23 prop, turning 2650, running light, no tower, I can hit 35 MPH on the top end. That is what 30 knots?

Bob,
That's why I wished to have worn hip boots.

Greetings all First time posting...

Ian,

I am in the middle of restoring a '72 Formula 233 and I have the same thing in my hull as does my buddy who also has a '73 233. I think it was a design thing they did in the 60-70's. My trailer is also a few inches shorter but it was there before I started ripping it apart.

Brian

$500 was what I was quoted twice for soda blasting my 20 bahia mar..


I'm going to boat this weekend I'll check the hull for a hook and let you know...


Ray

There is a Bertram 20 "speed boat" on a bunk trailer being finished next to where my boat is inside a large building here in Wilmington. I spoke with the owner yesterday.. he has 3 B20s.. the one I saw on the trailer (which is almost done, with a beautiful blue and white AwlFair 2000 paint job), another under a tarp in the same building which he says has a center console, and I think he said a third center console somewhere else. He seems to know a lot about the B20s, how many were made, where they went (apparently a lot of new ones went to Iran and Israel), when they were made, etc, etc.

I looked at the hull.. it looks like thre is a slight inward deformation where the bunks contact the hull.. but I can't confirm for sure. The bunks run from the transom to about 12" aft of the dashboard. Very pretty boat.. he expects to start rebuilding the CC next.

Thanks guys! Seems that many have somewhat of a hook.

I'm officially not worrying about it until she's in the water next spring.

Ian.